Synthesis of poly(1-hexene)s end-functionalized with phenols - Yanjarappa, Mallinamadugu J.; Sivaram, Swaminathan (Polymer International, 2005)
Electrophilic alkylations of phenol/2,6-dimethylphenol were performed with vinylidene-terminated poly(1-hexene)s using BF3-OEt2 catalyst. Vinylidene-terminated poly(1-hexene)s with M. varying from 400 to 10000 were prepared by bulk polymerization of 1-hexene at 50 to -20 degrees C using Cp2ZrCl2/MAO catalysts. The phenol/2,6-dimethylphenol-terminated poly(1-hexene)s was characterized by NMR (H-1, C-13), UV, IR and vapor phase osmometer (VPO). The isomer distribution (ortho, para and ortholpara) was determined by P-13 NMR using a phosphitylating reagent, namely 2-chloro-1,3,2-dioxaphospholane. The number-average degree of functionality (F-n) > 0.9 with > 95% para selectivity could be achieved using low-molecular-weight oligomers of poly(1-hexene)s. (c) 2005 Society of Chemical Industry.
Keywords: Alkylation; chain-end functionalization; functional poly(olefin)s; metallocene catalysts

Synthesis of rutile from ATO and stearic acid - Patil, M. M.; Deshpande, V. V.; Deshpande, S. B.; Samuel, V.; Ravi, V. (Materials Letters, 2005)
Nanocrystalline titanium dioxide in the rutile phase has been obtained from the solid state reaction between ammonium titanyl oxalate (ATO) and stearic acid at 400 degrees C in air. The fine powders of ATO and stearic acid are mixed well using acetone in an agate mortar and pestle for 2 h. This mixture (weight ratio of ATO to stearic acid > 5) on heating at 400 degrees C produces rutile powders. For the ratios of ATO to stearic acid < 5, a mixture of anatase and rutile phases is obtained. Pure ATO yields anatase phase on decomposition at 400 degrees C. These powders were characterized by X-ray diffraction (XRD), BET surface area measurements and transmission electron microscopy (TEM) studies. (c) 2005 Elsevier B.V. All rights reserved.
Keywords: Ceramics; Chemical synthesis; Electron microscopy; Oxides; X-ray techniques

Synthesis, structure, electrochemistry and ROMP-activity of new ferrocenyl analog of Grubbs' metathesis catalyst - Maishal, T. K.; Mondal, Biplab; Puranik, Vedavati G.; Wadgaonkar, P. P.; Lahiri, Goutam Kumar; Sarkar, A. (Journal of Organometallic Chemistry, 2005)
Treatment of [(PCy3)(2)Cl2Ru=CH-Ph] (1) with vinylferrocene 1 and 1-ferrocenyl-1,3-butadiene 2 yielded solid products. These new complexes were characterized by H-1 NMR, P-31 NMR and C-13 NMR spectroscopy. X-ray crystal structures of both the complexes have been solved. The crystal structure of II confirmed the assigned structure and revealed existence of two sets of intermolecular C-H-Cl(M) type interactions, viz. (Ru)Cl-H-C(ferrocene) and (Ru)Cl-H-CHCl2. The air-stable, dark solid II is all efficient catalyst for ring-opening metathesis polymerization (ROMP) of cyclopentene, norbornene and cycloocta-1,5-diene. Electrochemical behavior of the complexes clearly reflects electronic communication between two metal centers. (C) 2004 Elsevier B.V. All rights reserved.
Keywords: Electrochemistry; ferrocene; Metathesis; non-covalent interactions; ring-opening metathesis polymerization; ruthenium carbene

tert-Butylation of p-cresol over WOx/ZrO2 solid acid catalysts - Sarish, S.; Devassy, Biju M.; Halligudi, Shivaraj B. (Journal of Molecular Catalysis A - Chemical, 2005)
The tert-butylation of p-cresol with tert-butanol was carried out over WO3/ZrO2 catalysts under flow conditions, The catalysts were prepared by wet impregnation method using zirconium oxyhydroxide and ammonium metatungstate. Catalysts with different WO3 loading (5-30 wt.%) were prepared and calcined at 800 degrees C and catalyst with 15% WO,, was calcined from 600 to 900 C. The catalysts were characterized by surface area, XRD, FTIR and TEM. The catalyst 15% WO3/ZrO2 calcined at 800 degrees C found to be the most active in the reaction. The effect of temperature, space velocity and molar ratio of the reactants on the conversion of p-cresol and products selectivities were studied. Under the optimized reaction conditions of 130 degrees C, tert-butanol/p-cresol molar ratio of 3 and flow rate of 10 ml h(-1). p-cresol conversion was 69.8% with selectivity to 2-tert-butyl-p-cresol 92.4%, 2,6-di-tert-butyl-p-cresol 6.3% and p-cresol tert-butyl ether 1.3%. The catalytic activity is compared with sulfated zirconia, USY, H beta zeolites and montmorillonite K-10 under the optimized reaction conditions The activity of sulfated zirconia is lower than that of 15% WO3/ZrO2 catalyst calcined at 800 C and other catalysts showed very low activity, (c) 2005 Elsevier B.V.. All rights reserved.
Keywords: p-Cresol; tert-butylation; tungsten oxide; Zirconia

Tetrazine derived mononuclear Ru-II(acac)(2)(L)(1), [Ru-II(bpy)(2)(L)](ClO4)(2)(2) and [Ru-II(bpy)(L)(2)](ClO4)(2)(3) (L=3-amino-6-(3,5-dimethylpyrazol-1-yl)-1,2,4,5-tetrazine, acac = acetylacetonate, bpy=2,2 '-bipyridine): syntheses, structures, spectra - Nayak, A.; Patra, S.; Sarkar, B.; Ghumaan, Sandeep; Puranik, Vedavati G.; Kaim, Wolfgang; Lahiri, Goutam Kumar (Polyhedron, 2005)
Mononuclear ruthenium complexes of tetrazine derived L, Ru-II(acac)(2)(L) (1), [Ru-II(bpy)(2)(L)](ClO4)(2) (2) and [Ru-II(bpy)(L)(2)](ClO4)2 (3) (L = 3-amino-6-(3,5-dimethylpyrazol-1-yl)-1,2,4,5-tetrazine, acac = acetylacetonate and bpy = 2,2'-bipyridine) were prepared. The free L exists as a dimeric entity in the solid state via hydrogen bonding interactions involving L and water molecules present in the crystal lattice. 1 exhibits unusually strong bonds from Ru-II to coordinating pyrazolyl-N (2.040(2) Angstrom) and especially to tetrazine-N (1.913(2) Angstrom). The Ru-III/Ru-II couples of 1-3 appeared at 0.28, 1.34 and 1.50 V versus SCE, respectively. The tetrazine and bpy-based reductions were observed at -1.33 (1); -0.55 and -1.55/-1.75/-1.98 (2); -0.47/-0.78 and -1.80/-2.02 V (3), respectively. 1, 2 and 3 displayed two MLCT bands each, corresponding to dpi(Ru-II) --> pi* (L, tetrazine) and dpi(Ru-II) --> pi* (acac or bpy or L) transitions. 1(+) and 2(+) showed rhombic EPR spectra at 110 and 4 K, respectively and 1(-), 2(-) and 3(-) exhibited multiple line EPR spectra at 300 K. 1-3 exhibited moderately strong emission spectra in EtOH-MeOH glass at 77 K. (C) 2004 Elsevier Ltd. All rights reserved.
Keywords: Electrochemistry; redox; ruthenium-tetrazine; spectra; structure; synthesis

Thermal, magnetic and spectral studies of metal-quinone complexes Part III. radical coordination and hydrogen bonding mediated exchange interaction in copper-hydroxyquinone complex - Salunke-Gawali, S.; Rane, S. Y.; Boukheddaden, K.; Codjovi, E.; Linares, J.; Varret, F.; Bakare, P. P. (Journal of Thermal Analysis and Calorimetry, 2005)
The reaction of CuCl with 2HNQ, ( viz. 2- hydroxy- 1,4- naphthoquinone), in methanol results in [Cu-2( II, II)(4HNSQ)(2)(ONQ)(2)(H2O)(4)], Cu- 3 complex; [ where ONQ is the deprotonated oxidized form of ligand ( viz. 2- oxido- 1,4- naphthoquinone) and 4HNSQ one electron reduced tautomeric form of the ligand (i.e. 4- hydroxy - 1,2- naphthosemiquinone)]. The mixed valent redox ligation is confirmed in [ 9] by us. In present report complex Cu- 3 investigated by variable temperature magnetic susceptibility measurements ( SQUID), X and Q- band EPR, DSC and CV techniques. A break is observed in the chi(m)(-1) vs. T plot similar to 200 K in Cu- 3 which is attributed to a phase transition. In Cu- 3 a quintet state ( S= 2) is populated above 200 K by the molecular association of two exo Cu( II)( 4HNSQ) units via hydrogen bonding between Cu(ONQ) unit of endo ligands in dimer. Magnetic susceptibility data is treated with tetramer model with S= 1/2,1/2,1/2,1/2. The interdimer triplet- triplet interaction ( J) in two [ Cu( 4HNSQ)] units and intradimer ( zJ(1)) interaction between [ Cu( II)( 4HNSQ)] are best fitted with J= -50 cm(-1) and zJ(1)= 28 cm(-1), respectively, using g= 2.2. `Quintet- triplet' phase transition occurs with an enthalpy change of 31.83 kJ mol(-1) estimated from DSC. Cu( II)double left right arrow Cu( I) and NSQ double left right arrow CAT redox couples at E-1/2= 0.68 V and E-1/2 = -1.12 V, respectively are result of exo ligands and Cu( II) ions interaction, while shifts of ligand based peaks viz. NQ -> NSQ and NSQ double left right arrow CAT at - 0.44 and - 0.67 V towards positive potential on complexation are due to electron transfer interactions between endo ligand and Cu( II) ion.
Keywords: antiferromagnetic coupling; copper complexes; Lawsone; model complexes; quinones; triplet state

Thidiazuron-induced morphogenesis in tamarind seedlings - Mehta, Urmil J.; Sahasrabudhe, N.; Hazra, Sulekha (In Vitro Cellular & Developmental Biology-Plant, 2005)
Germination of tamarind seeds in medium containing thidiazuron (TDZ) resulted in induction of nodular protrusions in and around the cotyledonary node meristem. The structures developed radially in well-defined circles and subsequently spread towards the cotyledonary bridge and also in the proximal part of the hypocotyl. The structures developed into shoots on transfer to medium devoid of growth regulators. Histological studies revealed that the protrusions initiated from the nodal meristem and extended to the non-meristematic region between the two meristems and also in the proximal part of the hypocotyl in seedlings germinated in 9.08 mu M TDZ. Newly formed cell layers and less-differentiated meristematic protrusions were also seen. With the increase in the distance from the meristem, the buds were less differentiated; in the proximal part of the hypocotyl only the multiple layers of meristematic cells were noted. With extension of the period of incubation, the TDZ-induced meristematic activity extended laterally in circles towards the neighboring region. The radial spread of the meristematic activity from the center of the nodal meristem was also evident at 18.16 mu M TDZ. From the pattern of the morphogenic development and the histological studies it may be hypothesized that in tamarind, TDZ influences the existing meristems specifically. Subsequently de novo organogenesis is triggered in the neighboring cells.
Keywords: Caulogenesis; Histology; morphogenesis; protrusions; thidiazuron

Ti-oxo radicals and product selectivity in olefin oxidations over titanosilicate molecular sieves - Shetti, VN; Srinivas, D; Ratnasamy, P (Zeitschrift für Physikalische Chemie International Journal of Research in Physical Chemistry and Chemical Physics, 2005)
The O-O bond of Ti-oxo species (Ti-peroxo, Ti-hydroperoxo or Ti-superoxo) generated on titanosilicate molecular sieves contacted with H2O2 cleaves either heterolytically or homolytically. While the former type of O-O cleavage (generating non-radical reactive oxygen intermediates) leads to selective epoxide products, the latter (generating reactive oxygen radical intermediates, O-2(-center dot) and HOOcenter dot) results in non-sclective, allylic oxidation products in cyclohexene oxidation. These radicals were detected using EPR spin trapping techniques 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) was used as the spin trap. Radical quenchers like hydroquinone suppressed their concentration and enhanced epoxide selectivity.
Keywords: cyclic voltammetry of titanosilicates; EPR-spin trap experiments; Molecular sieves; oxidations; product selectivity; reactive oxygen species; titaniunz-oxo radicals; Titanosilicates

Titanium superoxide catalyzed selective oxidation of phenols to p-quinones with aq. H2O2 - Dewkar, Gajanan; Shaikh, T. M.; Pardhy, S.; Kulkarni, S. S.; Sudalai, A. (Indian Journal of Chemistry Section B-Organic Chemistry Including Medicinal Chemistry, 2005)
Titanium superoxide, a novel heterogeneous and readily accessible catalyst, is found to catalyze the selective oxidation of phenols to the corresponding 1,4-benzoquinones in preparative yields with aq. 30% H2O2 as oxidant under mild reaction conditions.

Transmetalation reaction between hydrophobic silver nanoparticles and aqueous chloroaurate ions at the air - Water interface - Pasricha, R; Swami, A; Sastry, M (Journal of Physical Chemistry B, 2005)
The transmetalation reaction between a sacrificial nanoparticle and more noble metal ions in solution has emerged as a novel method for creating unique hollow and bimetallic nanostructures. In this report, we investigate the possibility of carrying out the transmetalation reaction between hydrophobic silver nanoparticles assembled and constrained at the air-water interface and subphase gold ions. We observe that facile reduction of the subphase gold ions by the sacrificial silver nanoparticles occurs resulting in the formation of elongated gold nanostructures that appear to cross-link the sacrificial silver particles. This transmetalation reaction may be modulated by the insertion of an electrostatic barrier in the form of an ionizable lipid monolayer between the silver nanoparticles and the aqueous gold ions that impacts the gold nanoparticle assembly. Transmetalation reactions between nanoparticles constrained into a close-packed structure and appropriate metal ions could lead to a new strategy for metallic cross-linking of nanoparticles and generation of coatings with promising optoelectonic behavior.

Unusual stereochemical outcome of radical cyclization: synthesis of (+)-biotin - Chavan, Subhash P.; Chittiboyina, A. G.; Ramakrishna, G.; Tejwani, R. B.; Ravindranathan, T.; Kamat, Subhash K.; Rai, B.; Sivadasan, L.; Balakrishnan, K.; Ramalingam, S.; Deshpande, V. H. (Tetrahedron, 2005)
An enantioselective synthesis of (+)-biotin 1 starting from naturally available cysteine is described. The key steps are the unusual stereochemical outcome of radical cyclization of compound 10 to prepare 5,5-fused system 11, and the introduction of C4-sidechain at C-6 in 13 via a Grignard reaction. (c) 2005 Elsevier Ltd. All rights reserved.
Keywords: biotin; exocyclization; radical cyclization

Using the dynamic, expanding liquid-liquid interface in a Hele-Shaw cell in crystal growth and nanoparticle assembly - Rautaray, D; Kavathekar, R; Sastry, M (Faraday Discussions, 2005)
The liquid-liquid interface has been used with considerable success in the synthesis of advanced materials ranging from (bio)minerals to inorganic membranes to nanoparticles. In almost all such cases, the interface is static. The Hele-Shaw cell in which a viscous fluid is displaced by a less viscous one in a constrained manner has been invaluable in the study of dynamic instabilities at interfaces and in the study of viscous fingering pattern formation. However, the potential of the Hele-Shaw cell in carrying out reactions at the interface between the two fluids leading to the formation of inorganic materials has been largely unrecognized and underexploited. Realizing that the dynamic liquid-liquid interface in a Hele-Shaw cell would provide opportunities to control a variety of time-scales associated with material formation, we have started a program on the use of the Hele-Shaw cell in materials synthesis. In this discussion paper, we present some of our recent results on the growth of calcium carbonate crystals in the Hele-Shaw cell by the reaction of Ca2+ ions electrostatically complexed with carboxylate ions pinned to the interface with carbonate ions present in the aqueous part of the biphasic reaction medium. We show that both polymorph selectivity and the morphology of the crystals may be modulated by varying the experimental conditions in the cell. We also discuss the possibility of using the dynamic interface in the Hele-Shaw cell to cross-link gold nanoparticles in water through bifunctional linkers present in the oil phase and investigate the nature of the structures formed.

Vanadium-containing ordered mesoporous silicas: synthesis, characterization and catalytic activity in the hydroxylation of biphenyl - George, J.; Shylesh, S; Singh, AP (Applied Catalysis A - General, 2005)
A series of vanadium-containing ordered mesoporous MCM-41 materials (V-OMS) have been synthesized by direct hydrothermal (VMCM-41) and grafting (V/MCM-41) methods using hexadecyl trimethyl ammonium bromide (HDTMABr) as the structure-directing agent. The physico-chemical properties of the vanadium-containing materials were characterized in detail by ICP-OES, XRD, Fr-IR, N-2 adsorption-desorption, DRUV-VIS, TPR, XPS and SEM techniques. The redox performances of the vanadium-modified mesoporous materials were tested in the hydroxylation of biphenyl using aqueous H2O2 (30 wt.%) as oxidant. For a better exploitation of the catalytic activity, the reaction parameters are optimized in terms of temperature, solvent, oxidant, etc. A comparison between the catalytic activity values of the vanadium-containing mesoporous materials prepared by the two routes shows that vanadium-substituted (V-MCM-41) materials had increased activity and improved selectivity for mono hydroxyl products in the hydroxylation reaction of biphenyl compared to the V/MCM-41 catalysts. The heterogenity of the catalysts was verified by a series of leaching studies. Both the catalysts enhance the leaching of active vanadia species during the reaction; among them, V/MCM-41 shows the least heterogenity. (c) 2005 Elsevier B.V. All rights reserved.
Keywords: biphenyl; heterogenity; MCM-41; Mesoporous molecular sieves; Vanadium

Vanadium-containing ordered mesoporous silicates: does the silica source really affect the catalytic activity, structural stability, and nature of vanadium sites in V-MCM-41? - Shylesh, S; Singh, AP (Journal of Catalysis, 2005)
A series of vanadium-substituted mesoporous materials were synthesized hydrothermally with the use of two commonly used silica Sources. fumed silica and tetra ethyl orthosilicate. The extent of mesopore structural ordering was confirmed from X-ray diffraction, N-2 physisorption, SEM, and TEM, and the presence and nature of vanadium species inside the framework of the MCM-41 matrix was confirmed in detail with the use of various characterization techniques like FT-IR, Si-29 MAS NMR, DRUV-vis, EPR, V-51 MAS NMR, and Raman analysis. It is deduced from the above characterization techniques that, regardless of the silica source, vanadium is incorporated into the silica framework and thereby increases the structural ordering and wall thickness of the mesoporous material. Thermal and hydrothermal Studies performed over the V-MCM-41 catalysts show that the Si-O-Si inorganic backbone from a fumed silica source is more resistant to severe thermal treatments and hydrolysis than the tetraethyl orthosilicate-synthesized catalysts. Spectroscopic characterization reveals the existence of easily accessible isolated tetrahedral vanadium sites on V-MCM-41 catalyst prepared front fumed silica catalyst, whereas the sample obtained from a tetraethyl orthosilicate silica Source shows vanadium in more disordered sites. Catalytic results show that both catalysts display excellent activity toward the epoxidation reaction of bulkier olefins, and the exceptional activity of the fumed silica catalyst may arise from the more isolated tetrahedral sites and the complementary textural characteristics, which may facilitate the easy access of substrate to the isolated framework metal sites. (c) 2005 Elsevier Inc. All rights reserved.
Keywords: epoxidation; fumed silica; MCM-41; tetraethyl orthosilicate; Vanadium

X-ray crystallographic studies on C-phycocyanins from cyanobacteria from different habitats: marine and freshwater - Satyanarayana, L.; Suresh, C. G.; Patel, A.; Mishra, Satyendra; Ghosh, P. K. (Acta Crystallographica Section F-Structural Biology and Crystallization Communications, 2005)

Zeolite-based organic-inorganic hybrid catalysts for phosgene-free and solvent-free synthesis of cyclic carbonates and carbamates at mild conditions utilizing CO2 - Srivastava, R; Srinivas, D; Ratnasamy, P (Applied Catalysis A - General, 2005)
As-synthesized zeolite-beta exhibits high catalytic activity for the synthesis of cyclic carbonates and alkyl and aryl carbarnates by a phosgene-free route, utilizing the greenhouse effect gas CO2. The reaction occurs with high yields of the desired products at mild conditions and without using any solvent or cocatalyst. Cyclic carbonates are synthesized by cycloaddition reaction Of CO2 with oxiranes (epichlorohydrin, propene oxide, styrene oxide and n-butene oxide) at 393 K and 6.9 bar. Alkyl and aryl carbarnates are synthesized by the reaction of the corresponding amines, CO2 and n-butyl bromide at 353 K and 3.4 bar. The as-synthesized zeolite-beta containing the encapsulated quaternary ammonium ions is not only reusable in several recycling experiments, but also shows superior activity to that of the corresponding homogeneous, quaternary ammonium halide salt generally used in the commercial synthetic practice. The microporous silica (inorganic) acting in concert with the encapsulated organic component constitutes an efficient, recyclable catalyst for this reaction. (c) 2005 Elsevier B.V. All rights reserved.
Keywords: alkyl and aryl carbamates; carbon dioxide utilization; cyclic carbonate; phosgene-free synthetic route; Polycarbonate; zeolite-beta

Zirconia-supported phosphotungstic acid as catalyst for alkylation of phenol with benzyl alcohol - Devassy, Biju M.; Shanbhag, G. V.; Lefebvre, F.; Bohringer, Walter; Fletcher, Jack C. Q.; Halligudi, Shivaraj B. (Journal of Molecular Catalysis A - Chemical, 2005)
The liquid-phase alkylation of phenol with benzyl alcohol was carried out using zirconia-supported phosphotungstic acid (PTA) as catalyst. The catalysts with different PTA loadings (5-20 wt.% calcined at 750 degrees C) and calcination temperature (15 wt.% calcined from 650 to 850 degrees C) were prepared and characterized by (31)p MAS NMR and FT-IR pyridine adsorption spectroscopy. The catalyst with optimum PTA loading (15%) and calcination temperature (750 degrees C) was prepared in different solvents. 31p MAS NMR spectra of the catalysts showed two types of phosphorous species, one is the Keggin unit and the other is the decomposition product of PTA and the relative amount of each depends on PTA loading, calcination temperature and the solvent used for the catalyst preparation. The catalysts with 15% PTA on zirconia calcined at 750 degrees C showed the highest Bronsted acidity. At 130 degrees C and phenol/benzyl alcohol molar ratio of 2 (time, I h), the most active catalyst, 15% PTA calcined at 750 degrees C gave 98% benzyl alcohol conversion with 83% benzyl phenol selectivity. (c) 2004 Elsevier B.V. All rights reserved.
Keywords: Benzylation; phenol; Phosphotungstic acid; Zirconia

4-Formylazetidin-2-ones, synthon for the synthesis of (2R,3S) and (2S,3R)-3-amino-2-hydroxydecanoic acid (AHDA) - Shirode, N. M.; Deshmukh, A. R. A. S. (Tetrahedron, 2006)
An efficient synthesis of 3-amino-2-hydroxydecanoic acid (AHDA), a nonproteinogenic amino acid, using enantiopure 3-benzyloxy-4-formylazetidin-2-one as a building block is described. Both the enantiomers of AHDA have been synthesized from the corresponding enantiomer of 3-benzyloxy-4-formylazetidin-2-one in good yield and optical purity. (c) 2006 Published by Elsevier Ltd.
Keywords: Amino acids; azetidin-2-ones; Staudinger reaction; stereoselective synthesis; Wittig reaction

[6+3] cycloaddition of pentafulvenes with 3-oxidopyrylium betaine: a novel methodology toward the synthesis of 5-8 fused oxabridged cyclooctanoids - Krishnan, K. Syam; Sajisha, V. S.; Anas, S.; Suresh, C. H.; Bhadbhade, Mohan M.; Bhosekar, Gaurav V.; Radhakrishnan, K. V. (Tetrahedron, 2006)
Pentafulvenes undergo a facile [6+3] cycloaddition with 3-oxidopyrylium betaine, generated from the corresponding pyranulose acetate, leading to the formation of 5-8 fused oxabridged cyclooctanoids. The product is formed by a [6+3] cycloaddition, followed by a 1,5-hydrogen shift of the initially formed [6+3] adduct. The reaction was found to be general and a number of fulvenes with a wide range of substituents at the exocyclic double bond, that is, at the C6 position followed a similar reactivity pattern. The [6+3] adduct, a 5-8 fused oxabridged cyclooctanoid, is potentially amenable to a number of synthetic transformations due to the presence of an alpha, beta-unsaturated ketone and cyclopentadiene part. By selecting appropriately substituted fulvene and pyranulose acetates, it is possible to use this methodology for the synthesis of a wide range of 5-8 fused cyclooctanoids. The experimental results have been rationalized on the basis of theoretical calculations. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: fulvenes; oxabridged cyclooctanoids; oxidopyrylium betaine; [6+3] cycloaddition

Adsorption of octadecyltrichlorosilane on mesoporous SBA-15 - Mirji, S. A.; Halligudi, Shivaraj B.; Sawant, Dhanashri P.; Jacob, Nalini E.; Patil, K. R.; Gaikwad, A. B.; Pradhan, S. D. (Applied Surface Science, 2006)
Adsorption of octadecyltrichlorosilane (OTS) on mesoporous SBA-15 has been studied by using Brunauer-Emmett-Teller (BET) surface area analysis, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and thermo-gravimetric analysis (TGA) techniques. BET surface area analysis shows decrease of surface area from 930 to 416 m(2)/g after OTS adsorption. SEM pictures show close attachment of SBA-15 particles. EDAX measurements show increase of carbon weight percentage and decrease of oxygen and silicon weight percentage. XPS results closely support EDAX analysis. FTIR spectra shows presence of methyl (-CH3) and methylene (-CH2) bands and oriented OTS monolayer on SBA-15. Thermo-gravimetric analysis shows that the OTS adsorbed on SBA-15 are stable up to a temperature of 230 degrees C and that the OTS monolayers decompose between 230 and 400 degrees C. (c) 2005 Elsevier B.V. All rights reserved.
Keywords: Adsorption; OTS; SBA-15; Self-assembly; thermal stability

Amino functionalized novel cholic acid derivatives induce HIV-1 replication and syncytia formation in T cells - Salunke, Deepak B.; Ravi, D. S.; Pore, V. S.; Mitra, Debashis; Hazra, Braja G. (Journal of Medicinal Chemistry, 2006)
Synthesis of C-11 azido/amino functionalized cholic acid derivatives has been achieved in excellent yields. Contrary to the previous prediction of analogous compounds to be HIV-1 protease inhibitors, in the present study these novel cholic acid derivatives induced host cell fusion during the progress of HIV-1 infection and produced multinucleated giant cells. This is the first report of syncytia induction and enhancement of viral replication in HIV-1 infected T cells by cholic acid derivatives.

Analysis of single PEM fuel cell performances based on current density distribution measurement - Ghosh, P. C.; Wuester, T.; Dohle, H.; Kimiaie, N.; Mergel, J.; Stolten, D. (Journal of Fuel Cell Science and Technology, 2006)
A new in situ measurement method of mapping the current density distribution in polymer electrolyte fuel cells (PEFC) is used to analyze the performance of a fuel cell under different operating conditions. The present method is useful in investigating the current density distribution in a single cell as well as a stack, which carries the information about the local reactant activity over the electrode area It was found that the current density close to the gas inlets is strongly influenced by the reactants' relative humidity. The performance close to the gas outlets is greatly influenced by the inlet gas pressures and the stoichiometry factors of the reactant gases, mainly on the cathode side. It was also observed that the performance of the fuel cell drops with the increase in operating temperature if the reactant gases are not sufficiently humidified.
Keywords: current density distribution; fuel cell performance; PEFC

Analytically continued fock space multi-reference coupled-cluster theory: application to the shape resonance - Pal, Sourav; Sajeev, Y.; Vaval, Nayana (Chemical Physics, 2006)
The Fock space multi-reference coupled-cluster (FSMRCC) method is used for the study of the shape resonance energy and width in an electron-atom/molecule collision. The procedure is based upon combining a complex absorbing potential (CAP) with FSMRCC theory. Accurate resonance parameters are obtained by solving a small non-Hermitian eigen-value problem. We study the shape resonances in e(-)-C2H4 and e(-)-Mg. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: complex absorbing potential; correlated independent particle potential; Fock space multi-reference coupled-cluster theory; shape resonance

Assembly of hydrothermally stable ethane-bridged periodic mesoporous organosilicas with spherical and wormlike structures - Shylesh, S.; Jha, Ratnesh Kumar; Singh, A. P. (Microporous and Mesoporous Materials, 2006)
Hydrothermally stable periodic mesoporous organosilicas with spherical as well as wormlike frame structures were synthesised by two different synthesis routes using the silsesquioxane precursor, 1,2-bis (triethoxy silyl) ethane (BTEE) and surfactant octadecyl trimethyl ammonium (ODTA), under basic conditions. The materials were characterized by PXRD, SEM, TEM, N-2 adsorption-desorption, FT-IR, Si-29 MAS NMR, C-13 CP MAS NMR and TG-DTA techniques. Characterization techniques revealed that the morphology of the hybrid material prepared from pure silsesquioxane precursor resulted in spherical particles while a combination of tetra ethyl orthosilicate and 1,2-bis (triethoxy silyl) ethane (90:10 ratio) resulted in materials having wormlike structures. Hydrothermal stability of the hybrid material was evaluated by refluxing the sample under boiling water for various time periods and was compared with that of a periodic mesoporous silica material, Si-MCM-41. Results showed that the hybrid material is stable up to 100 h in boiling water, with the existence of d(100) peak, while the mesopore structure of Si-MCM-41 get destroyed even after a 12 h reflux time. The improved hydrothermal stability of the hybrid material is related to the more hydrophobic environment induced inside the pore channels, due to the presence of integrating ethane groups in the wall channels. (c) 2006 Elsevier Inc. All rights reserved.
Keywords: hybrid mesoporous materials; Hydrothermal stability; spherical particles; wormlike structures

Assembly of phase transferred nickel nanoparticles at air-water interface using Langmuir-Blodgett technique - Bala, Tanushree; Joshi, Bhagyashree; Iyer, Neelima; Sastry, Murali; Bhagavatula L. V. Prasad (Journal of Nanoscience and Nanotechnology, 2006)
Development of simple and efficient protocol for the synthesis of Ni nanoparticles in aqueous media and their subsequent phase transfer to organic media is reported. The synthesis of nickel nanoparticles in aqueous medium is accomplished by reducing the nickel nitrate with sodium borohydricle in presence of oleic acid. It results in the formation of nickel nanoparticles capped with oleic acid. The pristine oleic acid capped nickel nanoparticles were then phase transferred to nonpolar solvents such as toluene using stearic acid. The phase transfer was effective probably due to the space exchange between the oleic acid moiety and stearic acid molecules. The hydrophobized Ni thus obtained was organized at the air-water interface and it was observed that by controlling the pressure and concentration of hydrophobized Ni nanoparticles at air-water interface, linear ribbon like assemblies could be obtained. The organization process was followed by surface pressure-area isotherm measurement and Brewster Angle Microscopy.
Keywords: assembly; Langmuir-Blodgett technique; Ni nanoparticles; Phase transfer

Beta-lactam-azasugar hybrid as a competitive potent galactosidase inhibitor - Pandey, Ganesh; Dumbre, Shrinivas G.; Khan, Mohammad Islam; Shabab, M.; Puranik, Vedavati G. (Tetrahedron Letters, 2006)
A beta-lactam-azasugar hybrid (polyhydroxylated carbacephem) has been designed and synthesized as a potent glycosidase inhibitor. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: beta-Galactosidase; beta-lactam-azasugar; glycosidase inhibitor; hybrid molecules

Biodegradation of gamma-sterilised biomedical polyolefins under composting and fungal culture environments - Alariqi, Sameh A. S.; Kumar, A. P.; Rao, B. S. M.; Singh, R. P. (Polymer Degradation and Stability, 2006)
Polyolefin-based commodities are widely used as biomedical devices and food packaging after gamma-sterilisation. The aim of the present work was to study the effect of gamma-sterilisation on the biodegradation of polyolefins. Films of isotactic polypropylene, high-density polyethylene and ethylene-propylene (EP) copolymers were sterilised under gamma-radiation with doses of 10 and 25 kGy. Neat and sterilised samples were incubated in compost and fungal culture environments. The changes in functional groups, surface morphology and chain scission in polymer chains were characterized by FTIR spectroscopy, SEM and viscometric measurements, respectively. A gradual decrease in intrinsic viscosity [eta] and increase in carbonyl and hydroxyl regions in FTIR spectra were found for the gamma-sterilised samples as a function of increasing dose. Polypropylene was found to be more susceptible to both radio-oxidation and biodegradation. It was observed that in case of ethylene-propylene copolymers, extent of gamma-sterilisation and/or biodegradation depends on the composition and distribution of comonomers. Important surface erosion was detected by SEM, for higher sterilisation doses, after composting. (c) 2005 Elsevier Ltd. All rights reserved.
Keywords: Biodegradation; chain scission; Composting and fungal culture; gamma-sterilisation; Polyolefins

Characterization of polydimethylsiloxane rubber upon photochemical, thermal, salt-fog ageings and exposure to acid vapours - Delor-Jestin, Florence; Tomer, N. S.; Singh, R. P.; Lacoste, Jacques (E-Polymers, 2006)
The changes in the chemical structure and the physical properties of a filled crosslinked polydimethylsiloxane rubber were monitored as a function of various ageing factors. The variables included photochemical, thermal, salt-fog ageings and exposure to acid vapours. Unaged and aged samples were studied by IR spectroscopy, hardness measurements, Differential Scanning Calorimetry (DSC) and thermogravimetric analysis (TGA) coupled with IR spectroscopy. No significant oxidation was detected after all ageings, except for nitric acid treatment. The presence of aluminium trihydrate was clearly identified as responsible for the observed chemical changes. Then an important vulnerability of this filled silicone rubber towards the cross-linking reactions provoked by usual ageings was also detected. The DSC-thermoporosimetry measurements of the mesh size distribution gave a comparison of cross-linking densities for each ageing. The complementary analysis with TGA-IR allowed us to differenciate the thermal stability of the formulation after various ageings and to acquire new knowledge about thermal decomposition.

Chemo-, regio- and stereo-selective aerial oxidation of limonene to the endo-1,2-epoxide over Mn(Salen)-sulfonated SBA-15 - Saikia, Lakshi; Srinivas, D.; Ratnasamy, Paul (Applied Catalysis A-General, 2006)
Mn(Salen) complexes immobilized on sulfonic acid-functionalized SBA-15 molecular sieves (SBA-15-pr-SO3-Mn(Salen)) catalyze the Mukaiyama-type oxidation of R-(+)-limonene selectively to the 1,2-epoxide with molecular oxygen at 298 K (Salen = N,N-ethylenebis(salicylidenaminato)). The endo-diastereomer is formed with a diasteromeric excess of 39.8%. This catalyst exhibited higher catalytic activity than ``neat'' Mn(Salen) complexes directly supported on SBA-15 or zeolite-Y. A change in the oxidation state of Mn from +3 in the ``neat'' complex to +2 when immobilized on the sulfonated surface is a probable cause for the observed enhancement of catalytic activity. A part of the Mn complexes was leached out of the solid phase during the reaction. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: aerial oxidation of limonene; catalysis by Mn(Salen) complexes; chemo-; immobilized Mn Schiff base complexes; Mesoporous molecular sieves; Mukaiyama-type oxidation; regio- and stereo-selective epoxidation; sulfonic acid-functionalized SBA-15

Chemoselective anti-Markovnikov hydroamination of alpha,beta-ethylenic compounds with amines using montmorillonite clay - Joseph, Trissa; Shanbhag, G. V.; Sawant, D. P.; Halligudi, Shivappa B. (Journal of Molecular Catalysis A-Chemical, 2006)
The catalytic activity of montmorillonite clays as a catalyst for the hydroamination of alpha,beta-ethylenic compounds with amines was tested. Aniline and substituted amines reacted with alpha,beta-ethylenic compounds in the presence of catalytic amount of commercially available clay to afford exclusively anti-Markovnikov adduct in excellent yields. Aniline reacted with ethyl acrylate to yield only anti-Markovnikov adduct N-[2-(ethoxycarbonyl)ethyl] aniline (mono-addition product). No Markovnikov adduct (N-[1-(ethoxycarbonyl)ethyl]aniline and double addition product N,N-bis[2-(ethoxycarbonyl)ethyl]aniline were formed under selected reaction conditions. For a better exploitation of the catalytic activity in terms of increased activity and improved selectivity for the mono-addition product, the reaction parameters were optimized in terms of temperature, solvent, reactant mole ratio. Under optimized reaction conditions, montmorillonite clay K-10 showed a superior catalytic performance in the hydroamination of ethyl acrylate with aniline with a conversion of aniline to mono-addition product (almost 100% chemoselectivity) with a high rate constant 0.3414 min(-1) compared to the reported protocols. The dependence of conversion of aniline over different types of montmorillonite clays (K-10, K-20, K-30, Al-Pillared clay and untreated clay) has also been discussed. The activities of clay for the hydroamination of different aromatic and aliphatic amines have also been investigated. Under harsh reaction conditions (increased temperature and long reaction time) small amounts of di-addition products were observed. The kinetics data has been interpreted using the initial rate approach model. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: alpha; amines; anti-Markovnikov addition product; beta-ethylenic compounds; chemo-selective; hydroamination; K-10 montmorillonite clay

Claisen rearrangement of allyl phenyl ether over zeolites beta, mordenite and Y - Wagholikar, S. G.; Mayadevi, S.; Jacob, Nalini E.; Sivasanker, S. (Microporous and Mesoporous Materials, 2006)
The Claisen rearrangement of allyl phenyl ether (APE) to o-allylphenol was investigated over zeolites beta (BEA), mordenite (MOR) and Y (FAU) with different Si/Al ratios. Over the zeolite catalysts, the allylphenol cyclized to produce 2,3-dihydro-2-methyl benzofuran. Larger catalyst loading, higher reaction temperatures and longer run duration favored the formation of the ring compound. Conversion was small over MOR and FAU although they possessed higher acidity (as measured by the temperature programmed desorption of ammonia) compared to BEA. Studies using BEA revealed that the nature of the solvent influenced the reaction rate. The order of reactivity in the solvents was, benzene > EDC (1,2-dichloroethane) > toluene > TCE (1, 1,2,2-tetrachloroethane) >> ACN (acetonitrile). The intermediate allylphenol reacted with the aromatic solvents to produce byproducts when benzene and toluene were used as solvents. A kinetic analysis assuming first order series and parallel reactions is presented. (c) 2006 Elsevier Inc. All rights reserved.
Keywords: allyl phenyl ether; allylphenol; Benzofuran; Claisen rearrangement; zeolites

Cobalt-containing hexagonal mesoporous molecular sieves (Co-HMS): Synthesis, characterization and catalytic activity in the oxidation reaction of ethylbenzene - Bhoware, Shrikant S.; Shylesh, S.; Kamble, K. R.; Singh, A. P. (Journal of Molecular Catalysis A-Chemical, 2006)
Cobalt-containing hexagonal mesoporous materials (Co-HMS and Co/HMS) with different cobalt content were synthesized for the first time by direct hydrothermal and post-synthesis (grafting) method. The materials were characterized in detail by X-ray diffraction, BET surface area, N-2 sorption isotherms, SEM, TEM, UV-vis and XPS techniques. Powder X-ray diffraction pattern, N2 adsorption-desorption analysis and TEM analysis show the presence of hexagonal mesoporous structure, having Type W isotherms and reveals the typical wormhole-like morphology. Spectroscopic techniques like UV-vis and XPS reveal cobalt in +2 oxidation state and tetrahedrally coordinated. Liquid phase oxidation of ethylbenzene using TBHP (70 wt%) as an oxidant shows that the catalysts are highly active, under solvent free conditions as well as under lower cobalt concentrations. Leaching studies performed by hot filtration experiments show that the cobalt catalysts prepared by hydrothermal methods are stable, while the grafted catalysts show the leaching of cobalt under the reaction conditions. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: Co-HMS; ethylbenzene; HMS; hydrothermal; Oxidation

Co-catalyzed reductive cyclization of azido and cyano substituted alpha,beta-unsaturated esters with NaBH4: enantioselective synthesis of (R)-baclofen and (R)-rolipram - Paraskar, A. S.; Sudalai, A. (Tetrahedron, 2006)
Sodium borohydride in combination with a catalytic amount of CoCl, has been found to be an excellent catalytic system in reductive cyclizations of suitably substituted azido and cyano groups of alpha,beta-unsaturated esters to afford gamma and delta-lactams in high yields. The process has been demonstrated for the enantioselective synthesis of (R)-baclofen, (R)-rolipram, and (R)-4-fluorophenylpiperidinone, a key intermediate for (-)-paroxetine. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: Asymmetric synthesis; cobalt chloride; gamma and delta-lactams; reduction; sodium borohydride

Conjugate addition of a silyl ketene acetal to alpha,beta-unsaturated lactones - Gnaneshwar, Rudhramyna; Sivaram, S (Synthetic Communications, 2006)
{Conjugate addition of a silyl ketene acetal [
Keywords: acetals; deprotection; MoO3/SiO2; protection

Construction of conductive multilayer films of biogenic triangular gold nanoparticles and their application in chemical vapour sensing - Singh, Amit; Chaudhary, Minakshi V.; Sastry, Murali (Nanotechnology, 2006)
Metal nanoparticles are interesting building blocks for realizing films for a number of applications that include bio- and chemical sensing. To date, spherical metal nanoparticles have been used to generate functional electrical coatings. In this paper we demonstrate the synthesis of electrically conductive coatings using biologically prepared gold nanotriangles as the building blocks. The gold nanotriangles are prepared by the reduction of aqueous chloroaurate ions using an extract of the lemongrass plant (Cymbopogon flexuosus) which are thereafter assembled onto a variety of substrates by simple solution casting. The conductivity of the film shows a drastic fall upon mild heat treatment, leading to the formation of electrically conductive thin films of nanoparticles. We have also investigated the possibility of using the gold nanotriangle films in vapour sensing. A large fall in film resistance is observed upon exposure to polar molecules such as methanol, while little change occurs upon exposure to weakly polar molecules such as chloroform.

Control of stereoselectivity in 4-tert-butylphenol hydrogenation over a carbon-supported rhodium catalyst by carbon dioxide solvent - Hiyoshi, Norihito; Mine, Eiichi; Rode, Chandrashekhar V.; Sato, Osamu; Ebina, Takeo; Shirai, Masayuki (Chemistry Letters, 2006)
cis-4-tert-Butylcyclohexanol was obtained with a high cis ratio (cis/(cis + trans) = 0.9) in the hydrogenation of 4-tert-butylphenol over a carbon-supported rhodium catalyst along with hydrochloric acid in supercritical carbon dioxide solvent.

Convergent approach toward the synthesis of the stereoisomers of C-6 homologues of 1-deoxynojirimycin and their analogues: evaluation as specific glycosidase inhibitors - Pandey, Ganesh; Dumbre, Shrinivas G.; Khan, Mohammad Islam; Shabab, M. (Journal of Organic Chemistry, 2006)
A new and stereoselective strategy is developed to synthesize an appropriate template 9 to obtain C-6 homologues of 1-deoxyazasugars such as 1-deoxy-D-galactohomonojirimycin ( 5), 1-deoxy-4-hydroxymethyl-D-glucohomonojirimycin (6), and their enantiomers. The template 9 is also used to obtain neutral nonbasic pseudo-glyconolactam (8), C-4 amino, and methyl analogues of 1-deoxy- homonojirimycin as new analogues of 1- deoxyhomoazasugars. Compound 5 is found to be a potent and specific inhibitor to alpha-galactosidase (K-i = 1.7 mu M). Similarly compounds 6 (K-i = 28 mu M), ent-5 (K-i = 129 mu M), and ent-6 K-i = 12 mu M) exhibited specific inhibition of beta-glucosidase.

Copper-, ligand- and solvent-free synthesis of ynones by coupling acid chlorides with terminal alkynes - Palimkar, Sanjay S.; Kumar, P. Harish; Jogdand, Nivrutti R.; Daniel, Thomas; Lahoti, Rajgopal J.; Srinivasan, Kumar V. (Tetrahedron Letters, 2006)
A general and efficient copper-, ligand- and solvent-free synthesis of ynones by coupling of a wide range of acid chlorides with terminal alkynes catalyzed by palladium(II) acetate at room temperature is reported. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: ligandless; neat; ynones

Coprecipitation technique to prepare NaNbO3 and NaTaO3 - Samuel, V; Gaikwad, A. B.; Ravi, V (Bulletin of Materials Science, 2006)
A simple coprecipitation technique has been used successfully for the preparation of pure, ultrafine, single phases of NaNbO3 (NN) and NaTaO3 (NT). An alcoholic solution of ammonium carbonate and ammonium hydroxide was used to precipitate Na+ and Nb5+ (or Ta5+) cations under basic conditions as carbonate and hydroxide, respectively. On heating at 700 degrees C, these precursors produce respective products. For comparison, both NN and NT powders were also prepared by the traditional solid state method. The phase purity and lattice parameters were studied by powder X-ray diffraction (XRD). The particle size and morphology were studied by scanning electron microscopy (SEM).
Keywords: Ceramics; Chemical synthesis; Electron microscopy; electronic materials; Oxides; X-ray methods

Coprecipitation technique to prepare Sr0.5Ba0.5Nb2O6 - Murugan, A. Vadivel; Gaikwad, A. B.; Samuel, V.; Ravi, V. (Bulletin of Materials Science, 2006)
An aqueous mixture of ammonium oxalate and ammonium hydroxide was used to coprecipitate barium and strontium ions as oxalates and niobium ions as hydroxide under basic conditions. This precursor on calcining at 750 degrees C yielded Sr0.5Ba0.5Nb2O6 phase. This is a much lower temperature than that prepared by traditional solid state method (1000 degrees C) as reported for the formation of Sr0.5Ba0.5Nb2O6 (SBN). Transmission electron microscopic (TEM) investigations revealed that the average particle size was 80 nm for the calcined powders. The room temperature dielectric constant at I kHz was found to be 1100. The ferroelectric hysteresis loop parameters of these samples were also studied.
Keywords: Ceramics; Electron microscopy; ferroelectricity; Oxides; X-ray diffraction

Cu(OTf)(2) or Et3N-catalyzed three-component condensation of aldehydes, amines and cyanides: a high yielding synthesis of alpha-aminonitriles - Paraskar, Abhimanyu S.; Sudalai, Arumugam (Tetrahedron Letters, 2006)
Copper(II) triflate or Et3N have been found to catalyze, under ambient conditions, the addition of a cyanide anion, such as trimethylsilyl cyanide or acetone cyanohydrin, onto in situ generated imines, furnishing alpha-aminonitriles in excellent yields. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: aldehydes; aminonitriles; multicomponent reactions; organocatalyst; Strecker reaction

Cyclitol based metal complexing agents. preference for the extraction of lithium by myo-inositol based crown-4-ethers depends on the relative orientation of crown ether oxygen atoms - Dixit, Shailesh S.; Shashidhar, M. S.; Devaraj, Subramanian (Tetrahedron, 2006)
myo-Inositol derived crown-4-ethers in which two of the oxygen atoms in the crown ether moiety have different relative orientations were prepared. Metal picrate binding studies revealed that the crown ether having 1,3-diaxial orientation shows the highest selectivity for binding to lithium although the crown ether having 1,2-diequatorial orientation exhibited the highest binding constant for lithium picrate. These results suggest that relative binding affinity of metal ions to crown ethers can be tuned by varying the relative orientation of crown ether oxygen atoms. The relevance of these results to the previously observed regioselectivity during the O-substitution of myo-inositol orthoesters is discussed. (c) 2606 Elsevier Ltd. All rights reserved.
Keywords: crown ether; Cyclitol; Inositol; ligand; lithium; metal complex

Densities and heat capacities of the ammonia plus water plus NaOH and ammonia plus water plus KOH solutions - Salavera, D.; Libotean, S.; Patil, K. R.; Esteve, X.; Coronas, Alberto (Journal of Chemical and Engineering Data, 2006)
Ammonia + water + sodium hydroxide and ammonia + water + potassium hydroxide mixtures were chosen as potential candidates for absorption chillers driven by low-temperature heat sources. Heat capacity and density were studied between (293.15 and 353.15) K at a constant pressure of 1.8 MPa for these solutions using a heat flux Calvet-type calorimeter and a vibrating-tube densimeter, respectively. Measured data were well-correlated with temperature and composition using simple polynomial equations. The relative deviations between the experimental and calculated values in the density and heat capacity measurements were 0.20 % and 0.49 % for NH3 + H2O + NaOH solutions and 0.10 % and 0.36 % for NH3 + H2O + KOH solutions, respectively. Also, two density prediction methods were checked using the experimental data. Previously, it was necessary to measure the density of ammonia and hydroxide aqueous solutions in similar conditions. The results showed that both methods are suitable for predicting the density of these solutions.

Design and synthesis of fluconazole/bile acid conjugate using click reaction - Pore, Vandana S.; Aher, Nilkanth G.; Kumar, Manish; Shukla, Praveen K. (Tetrahedron, 2006)
Novel fluconazole/bile acid conjugates were designed and their regioselective synthesis was achieved in very high yield via Cu(I) catalyzed intermolecular 1,3-dipolar cycloaddition. These new molecules showed good antifungal activity against Candida species. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: 1; 2; 3-Triazole; Antifungal agent; bile acid; Click chemistry; fluconazole/bile acid conjugate

Development of a simple high-throughput screening protocol based on biosynthetic activity of Mycobacterium tuberculosis glutamine synthetase for the identification of novel inhibitors - Singh, Upasana; Sarkar, Dhiman (Journal of Biomolecular Screening, 2006)
A high-throughput screening protocol has been developed for Mycobacterium tuberculosis glutamine synthetase by quantitative estimation of inorganic phosphate. The K., values determined at pH 6.8 are 22 mM for L-glutamic acid, 0.75 mM for NH4Cl, 3.25 mM for MgCl2, and 2.5 mM for adenosine triphosphate. The K-m value for glutamine is affected significantly by the increase in pH of assay buffer. At the saturating level of the substrate, the enzyme activity at pH 6.8 and 25 degrees C is found to be linear up to 3 h. The reduction of enzyme activity is negligible even in presence of 10% DMSO. The Z' factor and signal-to-noise ratio are found to be 0.75 and 6.18, respectively, when the enzyme is used at 62.5 mu g/ml concentration. The IC50 values obtained at pH 6.8 for both L-methionine S-sulfoximine and DL-phosphothriacin are 500 mu M and 30 pM, respectively, which is lowest compared to the values obtained at other pH levels. The Beckman Coulter high-throughput screening platform was found to take 5 h 9 min to complete the screening of 60 plates. For each assay plate, a replica plate is used to normalize the data. Screening of 1164 natural product fractions/extracts and synthetic molecules from an in-house library was able to identify 12 samples as confirmed hits. Altogether, the validation data from screening of a small set of an in-house library coupled with Z' and signal-to-noise values indicate that the protocol is robust for high-throughput screening of a diverse chemical library.
Keywords: Beckman Coulter; biosynthetic activity; Glutamine synthetase; high-throughput screening; Mycobacterium tuberculosis

Differentially expressed gene transcripts in roots of resistant and susceptible chickpea plant (Cicer arietinum L.) upon Fusarium oxysporum infection - Nimbalkar, Suhas B.; Harsulkar, Abhay M.; Giri, Ashok P.; Sainani, Mohini N.; Franceschi, Vincent R.; Gupta, Vidya S. (Physiological and Molecular Plant Pathology, 2006)
Differentially expressed genes in chickpea, (Cicer arietinum L.) during root infection by Fusarium oxysportan f sp. ciceri Racel, were identified using cDNA-RAPD and cDNA-AFLP approaches. The former employed decamer primers on cDNA template and revealed nine differentially expressed transcripts in the resistant-infected chickpea variety. Among the 2000 transcript-derived fragments (TDFs) screened by cDNA-AFLP, 273 were differentially expressed in chickpea roots during Fusaritan infection. Only 13.65% of the TDFs were differentially regulated during pathogen challenge, while the other 86% were expressed non-differentially during the process of pathogen infection in chickpea roots. Nineteen TDFs, which expressed differentially in the resistant-infected chickpea variety were cloned and sequenced. Two of these TDFs were similar to transcription factors like WRKY proteins and 14-3-3 proteins, while three TDFs represented the NBS-LRR-type gene sequences. Two TDFs had sequence identity to genes known to have function in defense. The RAPID TDF CaFRi60 showed sequence identity to gamma-glutamyl-cysteine synthetase. Among the TDFs examined by cDNA-AFLP, 19 were confirmed by Reverse Northern blot to be differentially expressed. The data confirms the effectiveness of the cDNA-AFLP technique in detecting differentially expressed genes during pathogenesis. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: cDNA-AFLP; Chickpea; Cicer arietinum; differentially expressed genes; fusarium oxysporum; Transcriptome

Direct hydrothermal synthesis of highly ordered Sn-SBA-15 mesoporous materials - Shah, Pallavi; Ramaswamy, Arumugamangalam V.; Ramaswamy, Veda (Chemistry Letters, 2006)
Well-ordered Sn4+-incorporated mesoporous silica SBA-15 samples have been synthesized from tetraethyl orthosilicate (TEOS) and SnCl4 (Si/Sn = 114-15) using nonionic surfactants under a slightly higher pH medium (optimum H2O to HCl molar ratio) and characterized by XRD (an increase in lattice parameter), TEM (no SnO2 species) and UV-vis spectral (absorption at 211 nm) techniques to show that Sn4+ ions are in tetrahedral coordination in Sn-SBA-15.

Direct oxidation of H-2 to H2O2 over Pd-based catalysts: influence of oxidation state, support and metal additives - Choudhary, Vasant R.; Samanta, C.; Choudhary, Tushar V. (Applied Catalysis A-General, 2006)
The influence of oxidation state (reduced and oxidized), support (ZrO2, Ga2O3, CeO2, SiO2, H-beta, ThO2, CeO2-ZrO2, BPO4 and Pd/Al2O3) and precious metal additives (Au, Pt, Rh and Ru) on the direct H2O2 synthesis has been investigated over Pd-based catalysts. For all the supports investigated herein, the oxidized Pd catalysts showed significantly superior H2O2 yields as compared to their reduced counterparts. The effect of the Pd oxidation state was found to be more important for determining the H2O2 yields than the particle size and surface area properties of the catalyst system. An excellent correlation was observed between the H2O2 selectivity and H2O2 decomposition activity of the oxidized Pd catalysts. The oxidized Pd catalysts showed almost an order of magnitude lower H2O2 decomposition activity than the reduced catalysts. The H2O2 yield in the H-2 to H2O2 oxidation passed through a maximum with increase in the An concentration. Although a similar effect was also observed in case of Pt, Au was found to be a superior promoter for the direct H2O2 synthesis process. Addition of Rh and Ru was found to be detrimental for the H2O2 yields; these results can be explained in terms of increased H2O2 decomposition activity and/or enhanced H-2 to H2O reaction activity in their presence. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: decomposition; direct synthesis; H2O2; metal additives; oxidation state; Pd catalysts; supports

Direct synthesis of nanocrystalline silver from the reaction between silver carboxylates and n-trioctylphosphine - Charan, Shobhit; Singh, Narendra; Khanna, P. K.; Patil, K. R. (Journal of Nanoscience and Nanotechnology, 2006)
Neat n-Trioctylphosphine (TOP) has been used for the first ever time for reduction of silver nitrate and silver carboxylates (citrate, oleate, and myristate) under mild thermal reaction conditions. UV-visible absorption measurements of re-dispersible silver particles that were obtained by reduction of silver myristrate (product-IV) and silver nitrate (product-I) showed surface plasmon resonance absorption peak at 400 nm. The powder XRD pattern of fcc zero-valent silver resulted in diameters in the range of about 25-30 nm. TEM analysis showed particle diameter similar to that was observed by the XRD. FTIR spectroscopy revealed that the organics from the carboxylate group are retained by the nano-particles in case of product-IV however, presence of TOP is observed in product-I. It is found that when silver nitrate is reduced by TOP, spherical silver nano-particles with poor redispersity are formed but extended heating results in formation of long silver rods of micrometer size however, the re-dispersible nano-particles are easily formed when silver carboxylates are reduced by TOP.
Keywords: Chemical synthesis; Nanocrystalline; noble metal; XRD

Directed organization of gold nanoclusters on silver nanowires: a step forward in heterostructure assembly - Sharma, J.; Vivek, J. P.; Vijayamohanan, K. P.; Singh, P.; Dharmadhikari, C. V. (Applied Physics Letters, 2006)
We investigate the directed assembly of tridecylamine protected gold nanoclusters of 4-5 nm size on functionalized silver nanowires of 55-60 nm diameter and the electron transfer behavior of this integrated structure using transmission electron microscopy, non-contact atomic force microscopy, and scanning tunneling microscopy/spectroscopy. Linear I-V for bare silver nanowire suggests metallic behavior but high tunnel resistance indicates presence of insulating layer on the surface. Identical I-Vs obtained for isolated gold nanoparticle and heterostructure suggests that electron transport across nanowires in the latter is governed by gold nanoparticles in contrast to expected ballistic or diffusive transport along their length.(c) 2006 American Institute of Physics.

Effect of a focusing electric field on the formation of arc generated carbon nanotubes - Karmakar, Soumen; Nagar, Harshada; Pasricha, R.; Seth, T.; Sathe, V. G.; Bhoraskar, S. V.; Das, A. K. (Nanotechnology, 2006)
The effect of a focusing electric field on the formation of carbon nanotubes in a direct current arc-plasma is investigated. The hard deposits on the surface of the cathode are the main products, rich in multi-walled carbon nanotubes. It is seen that the focusing electric field has a distinct influence on the yield, purity and morphology of the nanotubes. The yield of the carbon nanotubes under the `focused field condition' has been found to be higher than that derived from the normal electrode configuration. It has been observed that the deposition of carbonaceous soot on the reactor wall is considerably reduced on application of the focusing electric field. Transmission electron microscopy has been used to determine the morphology of the nanotubes. In addition, Raman spectroscopy has helped in distinguishing the graphene-like structures from the disordered carbon networks and helped in analysing the morphology of the tubes. Thermal analysis gave a qualitative estimation of the relative yield of carbon nanotubes within the cathode deposits and their thermal stabilities. The crystalline nature of the samples has been confirmed by x-ray diffraction analysis. The results clearly indicate that the focusing electric field confines the positively charged carbon precursors within the cathode-anode space causing high relative yield and purity and has a distinct effect on controlling the inner diameter of the as-synthesized carbon nanotubes.

Effect of annealing on properties of ZrSe2 thin films - Hankare, P. P.; Asabe, M. R.; Kokate, A. V.; Delekar, S. D.; Sathe, D. J.; Mulla, Imtiaz S.; Chougule, B. K. (Journal of Crystal Growth, 2006)
Thin films of ZrSe2 have been prepared on stainless steel and fluorine-doped tin oxide-coated glass substrates using electrodeposition technique at potentiostatic mode. Double-distilled water containing precursors Zr and Se with ethylene diamine tetra-acetic acid disodium salt as a complexing agent was used to obtain good quality deposits by controlling the rate of reaction. The preparative parameters such as concentration of bath, deposition time, bath temperature, pH of the bath and annealing temperature have been optimized using photoelectrochernical (PEC) technique. The films deposited at optimum preparative parameters are annealed at different temperatures. The film annealed at 200 degrees C shows more photosensitivity. The as-deposited and annealed films at 200 degrees C have been characterized by X-ray diffraction (XRD), energy dispersive analysis by X-ray (EDAX), optical absorption and scanning electron microscopy (SEM). The XRD analysis of the as-deposited and annealed films showed the presence of polycrystalline nature with hexagonal crystal structure. EDAX study reveals that deposited films are almost stoichiometric. Optical absorption study shows the presence of direct transition and band gap energies are found to be 1.5 and 1.38 eV, respectively, for the as-deposited and annealed films. SEM study revels that the grains are uniformly distributed over the surface of substrate for the as-deposited as well as annealed film, which indicates formation of good and compact type of crystal structure. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: band gap; EDAX; Electrodeposition; PEC; SEM; XRD; ZrSe2 thin films

Effect of organic additives on the mitigation of volatility of 1-nitro-3,3 `-dinitroazetidine (TNAZ): next generation powerful melt cast able high energy material - Talawar, M. B.; Singh, Alok; Naik, N. H.; Polke, B. G.; Gore, G. M.; Asthana, S. N.; Gandhe, B. R. (Journal of Hazardous Materials, 2006)
1-Nitro-3,3'-dinitroazetidine(TNAZ) was synthesized based on the lines of reported method. Thermolysis studies on synthesized and characterized TNAZ using differential scanning calorimetry (DSC) and hyphenated TG-FT-IR techniques were undertaken to generate data on decomposition pattern. FF-IR of decomposition products of TNAZ revealed the evolution of oxides of nitrogen and HCN containing species suggesting the cleavage of C/N-NO(2) bond accompanied with the collapse of ring structure. The effect of incorporation of 15% additives namely, 3-amino-1,2,4-triazole(AT), 3,5-diamino-1,2,4-triazole (DAT), carbohydrazide (CHZ), 5,7-dinitrobenzofuroxan (DNBF), bis (2,2-dinitropropyl) succinate (BNPS), triaminoguanidinium nitrate (TAGN), 2,4,6-trinitrobenzoic acid (TNBA) and nitroguanidine (NQ) on the volatility of TNAZ was investigated by undertaking thermogravimetric analysis. The TG pattern brings out the potential of BNPS and TAGN as additives to mitigate the volatility of TNAZ. The influence of additives on thermal decomposition of pattern of TNAZ was also investigated by DSC. The DSC results indicated that the additives did not have appreciable effect on the melting point of TNAZ. Scanning electron microscopic (SEM) studies were carried out to investigate the effect of additives on morphology of TNAZ. This paper also discusses the possible mechanism involved in between the TNAZ and TAGN and BNPS. It appears that the formation of charge transfer complex formation between the TNAZ and TAGN/BNPS. The effect of addition of high explosives such as CL-20, HMX and RDX on thermo-physical characteristics of TNAZ is also reported in this paper. (c) 2005 Elsevier B.V. All rights reserved.
Keywords: melt castable explosive; morphological structure; synthesis; Thermolysis; trinitroazetidine (TNAZ); volatility behavior

Effect of thermal annealing on Fe40Ni38B18Mo4 thin films: modified Herzer model for magnetic evolution - Hysen, T.; Deepa, S.; Saravanan, S.; Ramanujan, R. V.; Avasthi, D. K.; Joy, Pattayil Alias; D Kulkarni, S.; Anantharaman, Maliemadom R. (Journal of Physics D-Applied Physics, 2006)
Magnetic properties of nano-crystalline soft magnetic alloys have usually been correlated to structural evolution with heat treatment. However, literature reports pertaining to the study of nano-crystalline thin films are less abundant. Thin films of Fe40Ni38B18Mo4 were deposited on glass substrates under a high vacuum of approximate to 10(-6) Torr by employing resistive heating. They were annealed at various temperatures ranging from 373 to 773K based on differential scanning calorimetric studies carried out on the ribbons. The magnetic characteristics were investigated using vibrating sample magnetometry. Morphological characterizations were carried out using atomic force microscopy (AFM), and magnetic force microscopy (MFM) imaging is used to study the domain characteristics. The variation of magnetic properties with thermal annealing is also investigated. From AFM and MFM images it can be inferred that the crystallization temperature of the as-prepared films are lower than their bulk counterparts. Also there is a progressive evolution of coercivity up to 573 K, which is an indication of the lowering of nano-crystallization temperature in thin films. The variation of coercivity with the structural evolution of the thin films with annealing is discussed and a plausible explanation is provided using the modified random anisotropy model.

Efficient protocol for genetic transformation and shoot regeneration of turmeric (Curcuma longa L.) via particle bombardment - Shirgurkar, M. V.; Naik, V. B.; von Arnold, S.; Nadgauda, R. S.; Clapham, D. H. (Plant Cell Reports, 2006)

Electrical bistability in a xanthene class molecule: conduction mechanisms - Rath, Arup Kumar; Sahu, Satyajit; Pal, Amlan J. (Applied Physics Letters, 2006)
The author study conduction mechanism in two conducting states of a bistable device at range. They find that in the electrical bistable devices, electrical switching is associated with a change in the conduction mechanism. Device current in the low-conducting state follows an injection-limited mechanism. The current in the high-conducting state conforms a bulk-dominated mechanism, namely, space-charge limited conduction with an exponential distribution of traps. The bistability has an associated memory phenomenon. The devices exhibit read-only and random-access memory applications for several hours.

Electrochemical organization of monolayer protected gold nanoclusters on single-walled carbon nanotubes: significantly enhanced double layer capacitance - Mahima, Subhramanyam; Chaki, N. K.; Sharma, J.; Kakade, Bhalchandra A.; Pasricha, R.; Rao, A. M.; Vijayamohanan, K. (Journal of Nanoscience and Nanotechnology, 2006)
This paper reports a novel electrochemical route for anchoring monolayer protected gold nanoclusters (size 8 +/- 0.2 nm) on single-walled carbon nanotube bundles, resulting in the formation of hybrid materials. Monolayer protected gold nanoclusters prepared by modified Brust synthesis route were organized on SWNT bundles by cycling-the potential in dichloromethane between -1 to +1 V at a scan rate of 50 mV/s. Monolayer protected nanoclusters in electrolyte solutions possess ionic space charge around them (double layer charging), making them suitable for organization on nanotube bundles, by tuning the electrostatic interactions. More significantly, analysis of the double layer capacitance of these hybrid materials shows almost ten times increase in capacitance compared to that of bare SWNT bundles. We believe that these hybrid materials are potentially useful in nanoelectronics.
Keywords: double layer capacitance; double layer charging; hybrid materials; monolayer protected gold nanoclusters; single-walled carbon nanotubes

Electron transfer behavior of monolayer protected nanoclusters and nanowires of silver and gold - Sharma, Jadab; Vivek, J. P.; Vijayamohanan, Kunjukrishna P. (Journal of Nanoscience and Nanotechnology, 2006)
Understanding the electron transfer behavior of nanometer sized, both metallic and semiconducting particles and wires is important due to the fundamental interest in size and shape dependent electronic properties and also because of its applications in nano-electronic devices like single electron transistors and molecular switches. Monolayer protected nanoclusters enable one simple and elegant method of synthesis of these types of metallic and semiconducting materials using interfacial chemistry as has been successfully used in several applications ranging from catalysis to molecular electronics. The success of this type of nanostructured materials is due in part to the well known protecting/stabilizing action of the ligands (also known as surface passivating/capping agents), which facilitate the synthesis and processing of these hydrophobic colloids in solution form. The present article discusses the electron transfer behavior of silver nanowires and nanoparticles with varied sizes. In particular, we have investigated the electrochemical properties of silver nanowires (diameter 70 nm, length several micrometers) and compared with the behavior of similar relatively larger sized nanoparticles (size 40 nm). A critical analysis of the redox behavior of silver nanowires and nanoparticles is presented in aqueous medium under various electrolytic conditions along with a comparison of analogous properties of smaller sized (2-7 nm) silver and gold nanoclusters.
Keywords: cyclic voltammetry; nanoclusters/nanoparticles; Nanowires

Enantioselective synthesis of (-)-cytoxazone and (+)-epi-cytoxazone, novel cytokine modulators via sharpless asymmetric epoxidation and L-proline catalyzed mannich reaction - Paraskar, Abhimanyu S.; Sudalai, Arumugam (Tetrahedron, 2006)
A short and efficient enantioselective synthesis of (-)-cytoxazone and its stereoisomer (+)-epi-cytoxazone, novel cytokine modulators, has been described with good yield and enantioselectivity. Ti-catalyzed Sharpless asymmetric epoxidation of allyl alcohol and L-proline catalyzed three-component Mannich reaction constitute the key steps in introducing stereogenicity into the molecule. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: aminohydroxylation; Asymmetric synthesis; epoxidation; Mannich reaction; Oxidation; Ozonolysis

Enantioselective synthesis of (S,S)-ethambutol using proline-catalyzed asymmetric alpha-aminooxylation and alpha-amination - Kotkar, Shriram P.; Sudalai, Arumugam (Tetrahedron-Asymmetry, 2006)
An efficient enantioselective synthesis of (S,S)-ethambutol, a tuberculostatic antibiotic, has been achieved in 99% ee via both proline-catalyzed alpha-aminooxylation and alpha-amination of n-butyraldehyde as the key step. (c) 2006 Elsevier Ltd. All rights reserved.

Enantioselective synthesis of (+)-(S,S)-reboxetine - Siddiqui, Shafi A.; Narkhede, Umesh C.; Lahoti, Rajgopal J.; Srinivasan, Kumar V. (Synlett, 2006)
An efficient enantioselective synthesis leading directly to (+)-(S,S)-reboxetine has been described from commercially available trans-cinnammyl bromide using Sharpless asymmetric dihydroxylation as the key step.
Keywords: coupling; Dihydroxylation; Hydrogenation; reboxetine; trans-cinnamyl bromide

Engaging zwitterions in carbon-carbon and carbon-nitrogen bond- forming reactions: a promising synthetic strategy - Nair, Vijay; Menon, Rajeev S.; Sreekanth, A. R.; Abhilash, N.; Biju, Akkattu T. (Accounts of Chemical Research, 2006)
An Account of carbon−carbon and carbon−nitrogen bond-forming reactions mediated by zwitterions generated by the addition of organic nucleophiles to activated unsaturated systems highlighting their synthetic potential is presented.

Eu3+ doped lanthanum oxide nanowhiskers: microwave hydrothermal synthesis, characterization and photoluminescence properties - Murugan, A. Vadivel; Viswanath, Annamraju Kasi; Kakade, Bhalchandra A.; Ravi, V.; Saaminathan, V. (Journal of Physics D-Applied Physics, 2006)
We report here a straightforward and rapid microwave - hydrothermal route providing an easy synthesis of Eu3+ doped La2O3 nanowhiskers. The nanostructured Eu3+ doped La2O3 is characterized by x-ray diffraction studies, scanning electron microscopy and photoluminescence (PL). The emission spectrum shows transitions from the excited 5D(0) state to F-7(J) (J = 0, 1, 2, 3, 4) levels of the Eu3+ ion. The most intense peak around 611 nm is due to the D-5(0) -> F-7(2) transition, expected from the Judd-Ofelt selection rules. PL spectra measurements demonstrate that the lanthanum oxide nanowhisker shows higher PL intensity.

Evidence for intergranular tunnelling in polyaniline passivated alpha-Fe nanoparticles - Sunny, Vijutha; Narayanan, T. N.; Sajeev, U. S.; Joy, Pattayil Alias; Kumar, D. Sakthi; Yoshida, Yasuhiko; Anantharaman, Maliemadom R. (Nanotechnology, 2006)
Nanoparticles are of immense importance both from the fundamental and application points of view. They exhibit quantum size effects which are manifested in their improved magnetic and electric properties. Mechanical attrition by high energy ball milling (HEBM) is a top down process for producing fine particles. However, fineness is associated with high surface area and hence is prone to oxidation which has a detrimental effect on the useful properties of these materials. Passivation of nanoparticles is known to inhibit surface oxidation. At the same time, coating polymer film on inorganic materials modifies the surface properties drastically. In this work a modified set-up consisting of an RF plasma polymerization technique is employed to coat a thin layer of a polymer film on Fe nanoparticles produced by HEBM. Ball-milled particles having different particle size ranges are coated with polyaniline. Their electrical properties are investigated by measuring the dc conductivity in the temperature range 10-300 K. The low temperature dc conductivity (I-V) exhibited nonlinearity. This nonlinearity observed is explained on the basis of the critical path model. There is clear-cut evidence for the occurrence of intergranular tunnelling. The results are presented here in this paper.

Factors influencing decomposition of H2O2 over supported Pd catalyst in aqueous medium - Choudhary, Vasant R.; Samanta, C.; Choudhary, Tushar V. (Journal of Molecular Catalysis A-Chemical, 2006)
Since H2O2 decomposition can result in selectivity/yield loss in the direct H2O2 synthesis process from H-2 and O-2 over supported Pd catalysts, it is important to have an enhanced understanding about the factors affecting the H2O2 decomposition reaction. Herein, detailed studies have been undertaken to investigate the influence of different factors, such as (a) nature and concentration of acid in reaction medium, (b) nature and concentration of halide in presence and absence of acid in reaction medium, (c) pretreatment procedures and (d) catalyst modification by incorporation of different halides, on the H2O2 decomposition reaction over a 5% Pd/C catalyst in aqueous medium at 25 degrees C. This study has shown that the H2O2 decomposition activity is profoundly influenced by all the above factors. The effectiveness of the acids in suppressing the H2O2 decomposition activity decreased in the following order: hydroiodic acid > hydrobromic acid > hydrochloric acid >> acetic acid > phosphoric acid > sulfuric acid > perchloric acid. The ability of the acid to decrease the H2O2 decomposition activity was found to very strongly depend on the nature of its associated anion. Halides, such as iodide, bromide and chloride were particularly effective in suppressing the H2O2 decomposition activity. Oxidation pretreatment of the catalyst was found to strongly suppress its H2O2 decomposition activity, while a reduction treatment was found to promote its activity. A gradual decrease in the H2O2 decomposition activity of the catalyst was observed with each successive usage due to in situ sub-surface oxidation of Pd by H2O2. Halide incorporation either via the reaction medium or prior catalyst modification had a similar qualitative effect on the H2O2 decomposition activity. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: acid; H2O2 decomposition; H2O2 synthesis; halides; Pd catalysts; pretreatment

Fe-Zn double-metal cyanide complexes as novel, solid transesteritication catalysts - Srivastava, R.; Srinivas, D.; Ratnasamy, P. (Journal of Catalysis, 2006)
Fe-Zn double-metal cyanide complexes are currently used as catalysts for the ring-opening polymerization of epoxides, as well as the coupling of epoxides and CO2 for the production of polycarbonates. We report their novel application as highly efficient solid catalysts for the transesterification reactions of carbonates. The catalysts were prepared from aqueous solutions of ZnCl2 and K4Fe(CN)(6) in the presence of tert-butanol (complexing agent) and tri-block copolymer EO20PO70EO20 (average molecular weight, 5800; co-complexing agent). They were characterized by chemical analysis, XRD, thermal analysis, N-2 adsorption, magnetic susceptibility, SEM, and FTIR, diffuse reflectance UV-visible, EPR, and X-ray photoelectron spectroscopies. Their acidity was determined from the IR spectra of adsorbed pyridine and the temperature-programmed desorption of NH3. Catalyst samples prepared with both complexing and co-complexing agents were found to be more acidic and catalytically active than those prepared without these agents. These catalysts are more active/selective than other solid catalysts hitherto reported. Dimethyl carbonate, for example, could be synthesized with 100% selectivity and an isolated yield of >86% by the reaction of propene carbonate with methanol. The catalysts can be recycled without significant loss in activity. Lewis acidic Zn ions are the possible active sites for the transesterification reaction. (c) 2006 Published by Elsevier Inc.
Keywords: cyclic carbonate; Dimethyl carbonate; double metal cyanide Fe-Zn complexes; organic carbonate; transesterification catalyst

First study of metal hybrids of boronic acids: second-sphere coordination networks in the structures of 4-carboxyphenylboronic acid with some transition metals - Seethalekshmi, N.; Pedireddi, V. R. (Inorganic Chemistry, 2006)
Metal-organic hybrids of a boronic acid (4-carboxylphenylboronic acid) with Co(II), Mn(II), and Ni(II) salts have been reported for the first time. In all of the complexes, there is no interaction between the metal and boronic acid through dative bonds. Furthermore, second-sphere coordination, along with water clusters in the form of octamers, was observed in the absence of any other additional ligands. However, in the presence of aza-donor molecules such as 1, 2-bis(4-pyridyl) ethane, metal ions formed coordination polymers with those ligands, replacing the second-sphere coordination.

Flufenoxuron, an acylurea insect growth regulator, alters development of Tribolium castaneum (Herbst) (Coleoptera :tenebrionidae) by modulating levels of chitin, soluble protein content, and HSP70 and p34(cdc2) in the larval tissues - Salokhe, S.; Sarkar, A.; Kulkarni, A.; Mukherjee, Samindra N.; Pal, J. K. (Pesticide Biochemistry and Physiology, 2006)
The effect of sublethal concentrations, 0.00141% (LC20), 0.00251% (LC30), and 0.0036% (LC40) of a dispersible formulation of an acylurea insect growth regulator, flufenoxuron (Cascade) on certain biochemical parameters in the larvae of Tribolium castaneum was investigated. When neonates were fed on diet treated with sublethal concentrations for 24 It, it was observed that at all concentrations tested, there was a significant reduction in chitin content on the 15th day of development. Total soluble protein content at LC20 and LC30 decreased with increasing age of the larvae. At LC20 and LC40 concentrations there was a progressive increase in the protein: chitin ratio as a function of increase in age of the larvae. SDS-PAGE analysis of the larval tissue extracts indicated gross quantitative changes in some of the protein bands (MW 50-97 kDa). Western blot analysis revealed significant increase in the level of HSP70 in the extracts of larvae fed on LC30 treated diet, on the 7th and 10th day of development in the decreasing order. Conversely, a significant decrease in the hyper-phosphorylated form of p34(cdc2) kinase due to flufenoxuron treatment indicating modulation of cell cycle regulation was observed. Thus, sublethal concentrations of flufenoxuron alter expression of developmentally regulated proteins, HSP70 and p34(cdc2) and chitin formation in a stage-specific manner thereby resulting developmental abnormalities in T castaneum. (c) 2005 Elsevier Inc. All rights reserved.
Keywords: chitin; Development; flufenoxuron; HSP70; p34(cdc2); phosphotyrosine; sublethal effects; total soluble proteins; Tribolium castaneum

Formation of linear polymers with pendant vinyl groups via inclusion complex mediated polymerization of divinyl monomers - Satav, S. S.; Karmalkar, Rohini N.; Kulkarni, M. G.; Mulpuri, Nagaraju; Sastry, G. N. (Journal of the American Chemical Society, 2006)

Formation of poly(o-anisidine) coatings on copper from aqueous salicylate solution - Chaudhari, Sudeshna; Mandale, A. B.; Patil, K. R.; Sainkar, S. R.; Patil, P. P. (Surface & Coatings Technology, 2006)
Poly(o-anisidine) coatings have been electrosynthesized by using cyclic voltammetry on copper from an aqueous salicylate medium. Cyclic voltammetry, UV-visible absorption spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray photoelectron spectroscopy were used to characterize these coatings, which indicates that the aqueous salicylate solution is a suitable medium for the electrochemical polymerization of o-anisidine on copper substrate. Cyclic voltammetry accompanied by the X-ray photoelectron spectroscopy was used to characterize the surface modifications induced by polarizing the copper substrate in the aqueous salicylate solution (without monomer). It was shown that the polarization of the copper in the aqueous salicylate medium results into the passivation of its surface via the formation of Cu(2)O and/or copper salicylate complex. It was found that the electrochemical polymerization of o-anisidine takes place after the passivation of the copper substrate via fort-nation of Cu(2)O and/or copper salicylate complex and results into the formation of shiny, uniform and strongly adherent poly(o-anisidine). The optical absorption spectroscopy reveals the formation of emraldine salt form of poly(o-anisidine). This study offers an electrochemical polymerization recipe to synthesize strongly adherent poly(o-anisidine) coating on copper from aqueous media for possible use in corrosion protection application. (c) 2005 Elsevier B.V. All rights reserved.
Keywords: conducting polymers; Copper; corrosion protective coatings; cyclic voltammetry; poly(o-anisidine) coatings

Friction of a slider on a granular layer: non-monotonic thickness dependence and effect of boundary conditions - Siavoshi, Saloome; Orpe, Ashish V.; Kudrollim, Arshad (Physical Review E, 2006)
We investigate the effective friction encountered by a mass sliding on a granular layer as a function of bed thickness and boundary roughness conditions. The observed friction has minima for a small number of layers before it increases and saturates to a value that depends on the roughness of the sliding surface. We use an index-matched interstitial liquid to probe the internal motion of the grains with fluorescence imaging in a regime where the liquid has no significant effect on the measured friction. The shear profiles obtained as a function of depth show a decrease in slip near the sliding surface as the layer thickness is increased. We propose that the friction depends on the degree of grain confinement relative to the sliding surfaces.

Fungus-mediated biotransformation of amorphous silica in rice husk to nanocrystalline silica - Bansal, Vipul; Ahmad, Absar; Sastry, Murali (Journal of American Chemical Society, 2006)
Rice husk is a cheap agro-based waste material, which harbors a substantial amount of silica in the form of amorphous hydrated silica grains. However, there have been no attempts at harnessing the enormous amount of amorphous silica present in rice husk and its room-temperature biotransformation into crystalline silica nanoparticles. In this study, we address this issue and describe how naturally deposited amorphous biosilica in rice husk can be bioleached and simultaneously biotransformed into high value crystalline silica nanoparticles. We show here that the fungus Fusarium oxysporum rapidly biotransforms the naturally occurring amorphous plant biosilica into crystalline silica and leach out silica extracellularly at room temperature in the form of 2-6 nm quasi-spherical, highly crystalline silica nanoparticles capped by stabilizing proteins; that the nanoparticles are released into solution is an advantage of this process with significant application and commercial potential. Calcination of the silica nanoparticles leads to loss of occluded protein and to an apparently porous structure often of cubic morphology. The room-temperature synthesis of oxide nanomaterials using microorganisms starting from potential cheap agro-industrial waste materials is an exciting possibility and could lead to an energy-conserving and economically viable green approach toward the large-scale synthesis of oxide nanomaterials.

Gamma-heteroatom directed stereocontrolled staudinger cycloaddition reaction of vinylketenes and imines - Shaikh, Aarif L.; Puranik, Vedavati G.; Deshmukh, A. R. A. S. (Tetrahedron Letters, 2006)
Vinylketenes possessing a gamma-heteroatom, on Staudinger cycloaddition reaction with imines gave trans-3-vinyl-beta-lactams in very good yields. The vinyl side chain stereoselectively adopts the Z-configuration in the transition state to stabilize the vinylketene and produces, exclusively, trans-3-vinyl-beta-lactams. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: imines; Staudinger reaction; stereoselective synthesis; vinylketenes

Genetic diversity analysis in Gaultheria fragrantissima wall. (Ericaceae) from the two biodiversity hotspots in India using ISSR markers - Apte, G. S.; Bahulikar, R. A.; Kulkarni, R. S.; Lagu, Meena D.; Kulkarni, B. G.; Suresh, H. S.; Rao, P. S. N.; Gupta, V. S. (Current Science, 2006)
Our study involves Inter Simple Sequence Repeat markers to analyse genetic diversity of an undershrub, Gaultheria fragrantissima Wall. (Ericaceae) from two plant diversity hotspots in India, namely Western Ghats and Northeastern Himalayas. The plants from these two regions show no morphological differences but the total heterozygosity (H-T = 0.505) is high. Furthermore, the average heterozygosity of G. fragrantissima at WG (H-s = 0.433) is higher than that at NE region (H-s, = 0.231). Within population variance is higher (15.56 %) than among population variance (8.31 %) as seen in outcrossing plant species. Mantel's test shows a strong positive correlation between the genetic and geographic distances. The plants within WG show high gene flow, which may be enough to prevent genetic drift, however, the gene flow in NE population is very low.
Keywords: Gaultheria fragrantissima; Genetic diversity; heterozygosity; ISSR markers

Green protocol for the synthesis of N-oxides from secondary amines using vanadium silicate molecular sieve catalyst - Phukan, P.; Khisti, R. S.; Sudalai, A. (Journal of Molecular Catalysis A-Chemical, 2006)
Vanadium silicate molecular sieve catalyst VS-I was found to promote efficiently the oxidation of alpha alpha,alpha'alpha'-tetrasubstituted secondary amines with 30% aqueous hydrogen peroxide as oxidant. In comparison to other catalysts reported to date, this heterogeneous catalyst offers a remarkably simple workup procedure and is reusable without any appreciable loss of activity. (c) 2005 Elsevier B.V. All rights reserved.
Keywords: heterogeneous catalyst; Hydrogen peroxide; N-oxide; VS-1; zeolite

Heterogenized vanadyl cations over modified silica surfaces: a comprehensive understanding toward the structural property and catalytic activity difference over mesoporous and amorphous silica supports - Shylesh, S.; Singh, A. R. (Journal of Catalysis, 2006)
Using a postsynthesis grafting method, 3-aminopropyltriethoxysilane (3-APTS) was functionalized over silica gel and mesoporous silica materials like SBA-15 and MCM-41. Vanadyl cations were then immobilized over the functionalized amino groups of the silica samples and used as a catalyst in the liquid-phase oxidation reaction of cyclohexane. Elemental analysis, PXRD, TEM, N-2 adsorption-desorption isotherms, FTIR, C-13 and Si-29 MAS NMR, UV-vis, and EPR techniques were used to characterize the developed materials. Characterization results suggest that the percentage of 3-APTS grafting depends on the number of isolated and genlinal silanol sites of the support material, the solvents used during the grafting reactions, and the sample pretreatment conditions. We found that using toluene as the dispersing medium and Si-MCM-41 as a support provides the maximum amount of amine functionalization, and thereby the highest percentage of vanadium immobilization. Catalytic activity and metal leaching studies show that vanadium-immobilized mesoporous solids are more active and stable than the silica gel-functionalized vanadium catalyst and a framework-substituted V-MCM-41 catalyst. The enhanced activity and stability of the immobilized vanadium catalysts compared with the V-MCM-41 and silica gel samples are attributed to the active metal site isolations, as well as to the spatial restrictions imparted from the concave silica surfaces of the mesoporous solids rather than the convex silica surfaces of the silica gel sample. (c) 2006 Published by Elsevier Inc.
Keywords: 3-APTS; mesoporous solids; Oxidation; Silica gel; Vanadium

Heteropoly acid supported on titania as solid acid catalyst in alkylation of p-cresol with tert-butanol - Kumbar, Suresh M.; Shanbhag, G. V.; Lefebvre, F.; Halligudi, Shivaraj B. (Journal of Molecular Catalysis A-Chemical, 2006)
Butylation of p-cresol with tert-butanol was investigated on titania modified with 12-tungstophosphoric acid (TPA/TiO2) catalyst under vapor phase conditions. Catalysts with different TPA loadings (10-25 wt.%) and calcination temperatures (650-750 degrees C) were prepared by suspending titanium hydroxide in methanol solution of TPA followed by drying and calcination. These catalysts were characterized by surface area, XRD, P-31 MAS NMR, XPS, NH3-TPD, and FTIR pyridine adsorption. XRD results indicated that the presence of TPA retarded the crystallization of titania and stabilized TiO2 in anatase phase. P-31 MAS NMR indicated the presence of TPA in various forms (dispersed, highly fragmented and Keggin intact). These catalysts showed both Bronsted and Lewis acidity, and 20% TPA on TiO2 calcined at 700 degrees C (from here after words 20% TT 700) had the highest Bronsted as well as total acidity. Further, the catalytic activities were examined in tert-butylation of p-cresol with tent-butanol. The catalytic activity depended on TPA coverage, and the highest activity corresponded to the monolayer of TPA on titania. The most active catalyst 20% TT-700 gave 82% conversion of p-cresol and 89.5% selectivity towards 2-tert-butyl cresol (TBC), 2,6-di-tert-butyl cresol (DTBC) 7.5% and cresol-tert-butyl ether (CTBE) 3% under optimized conditions. The activity was always higher than that of WO3/ZrO2, sulfated zirconia (SZ), USY, H-beta zeolites and montmorillonite K-10 (K-10mont) under similar conditions. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: 2; 2-tert-butyl-p-cresol; 6-di-tert-butyl-p-cresol; Alkylation; heteropoly acid; p-Cresol; tert-butanol; titania

Highly acidic phytase from Aspergillus niger NCIM 563 under submerged fermentation - Soni, S. K.; Khire, Jayant Malhar (FEBS Journal, 2006)

High-throughput screening of RNA polymerase inhibitors using a fluorescent UTP analog - Bhat, Jyothi; Rane, Rajendra; Solapure, Suresh M.; Sarkar, Dhiman; Sharma, Umender; Harish, M. N.; Lamb, Sarah; Plant, Darren; Alcock, Peter; Peters, Steve; Barde, Shubhada; Roy, Raman K. (Journal of Biomolecular Screening, 2006)
RNA polymerase (RNAP) is a well-validated target for the development of antibacterial and antituberculosis agents. Because the purification of large quantities of native RNA polymerase from pathogenic mycobacteria is hazardous and cumbersome, the primary screening was carried out using Escherichia coli RNAP. The authors have developed a high-throughput screening (HTS) assay to screen for novel inhibitors of RNAP. In this assay, a fluorescent analog of UTP, gamma-amino naphthalene sulfonic acid (gamma-AmNS) UTP, was used as one of the nucleotide substrates. Incorporation of UMP in RNA results in the release of gamma-AmNS-PPi, which has higher intrinsic fluorescence than (gamma-AmNS) UTP. The assay was optimized in a 384-well format and used to screen 670,000 compounds at a concentration of 10 mu M. About 0.1% of the compounds showed more than 60% inhibition in the primary HTS. All the primary actives tested for dose response using the same assay had an EC50 below 100 mu M. Eighty percent of the primary HTS actives obtained using E. coli RNAP showed comparable activity against Mycobacterium smegmatis RNAP in the conventional radioactive assay. Activity of hits selected for the hit-to-lead optimization was also confirmed against Mycobacterium bovis RNAP which has > 99% sequence identity with Mycobacterium tuberculosis RNAP subunits.

Hybrid foldamer with unique architecture from conformationally constrained aliphatic-aromatic amino acid conjugate - Srinivas, Deekonda; Gonnade, Rajesh G.; Ravindranathan, Sapna; Sanjayan, Gangadhar J. (Tetrahedron, 2006)
In this paper, we describe the design and synthesis of a novel hybrid foldamer, derived from a conformationally constrained aliphatic-aromatic amino acid conjugate that adopts a well-defined, compact, three-dimensional structure, governed by a combined conformational restriction imposed by the individual amino acids from which the foldamer is composed. Conformational investigations confirmed the prevalence of a unique doubly bent conformation for the foldamer, in both solid and solution states, as evidenced from single crystal X-ray and 2D NOESY studies, respectively. The findings suggest that constrained aliphatic-aromatic amino acid conjugates offer new avenues for the de novo design of hybrid foldamers with distinctive structural architectures. Furthermore, the de novo design strategy disclosed herein has the potential for significantly augmenting the `tool-box' of the modern day peptidominetic chemist, as well as providing a novel approach to the field of rational design. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: Amino acids; Conformation; Foldamer; Peptidomimetics

Hydrophobic effects are dominant over secondary orbital interactions for a simple Diels-Alder reaction in salt solutions - Sarma, D.; Kumar, Anil (Organic Letters, 2006)
The stereoselectivity ratios for a Diels-Alder reaction between cyclopentadiene with methyl trans-crotonate carried out in salt solutions demonstrate the dominance of hydrophobic effects over secondary orbital interactions.

Hydrophobic effects in a simple Diels-Alder reaction in water - Sarma, D.; Pawar, S. S.; Deshpande, Suvarna S.; Kumar, Anil (Tetrahedron Letters, 2006)
The endolexo ratio for a simple Diels-Alder reaction carried out in water has been used to argue that hydrophobic effects can dominate the geometries of the transition states. (c) 2006 Elsevier Ltd. All rights reserved.

Hydrophobic, solid acid catalysts for production of biofuels and lubricants - Sreeprasanth, Pulinthanathu Sree; Srivastava, R.; Srinivas, D.; Ratnasamy, P. (Applied Catalysis A-General, 2006)
A novel application of Fe-Zn double-metal cyanide (DMC) complexes as solid catalysts in the preparation of fatty acid alkyl esters (biodiesel/biolubricants) from vegetable oils is reported. The catalysts are hydrophobic (no H2O adsorption at reaction temperatures) and contain only Lewis acidic sites (NH3 and pyridine adsorption). Bronsted acid sites are absent (absence of 1546 and 1639 cm(-1) bands on adsorption of pyridine). Basic sites are also absent (no CO2 adsorption). Unlike the homogeneous or other solid catalysts (like ZnO-Al2O3, for example), the Fe-Zn, DMC catalysts are highly active even for the simultaneous transesterification of triglycerides and esterification of the free fatty acids (FFA) present in unrefined and waste cooking oils as well as non-edible oils. They are also tolerant of water, probably, due to their surface hydrophobicity. A relationship between the transesterification activity and the concentration of strong Lewis acid sites has been observed. Coordinatively unsaturated Zn2+ ions in the structure of the Fe-Zn complex are the probable active sites. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: alcoholysis of vegetable oils; Biodiesel; Biolubricants; double-metal cyanides (DMC); esterification of free fatty acids; fatty acid alkyl esters; fatty acid methyl esters; solid Fe-Zn catalysts; transesterification of vegetable oils

Hydrothermal synthesis of MCM-41 using differently manufactured amorphous dioxosilicon sources - Gaydhankar, T. R.; Samuel, V.; Joshi, P. N. (Materials Letters, 2006)
The influence of differently manufactured amorphous dioxosilicon sources such as fumed silica (FS), spray dried precipitated silica (PSI) and flash dried precipitated silica (PS,) on the course of structural development and properties of hydrothermally prepared siliceous MCM-41 phases have been investigated. Powder XRD, N-2 adsorption/desorption and scanning electron microscopy techniques were used for sample characterization. On the basis of results obtained from time dependent study on the progressive development of MCM-41 mesophases, the reactivity trend of dioxosilicon sources observed was as: FS > PS1 > PS2. MCM-41 synthesized using least expensive PS2 having less surface area has exhibited thicker pore walls but poor orderness, while MCM-41 prepared from expensive FS having high surface area has thinner pore walls and was well ordered. The extent of contraction caused by calcination, magnitude of the wall thickness and structural stability were found to be dependent on manufacturing process of dioxosilicon sources. The noticeable morphological differences were also observed by variations in the type of dioxosilicon sources used in the hydrothermal synthesis MCM-41 materials. (c) 2005 Elsevier B.V. All rights reserved.
Keywords: Characterization; dioxosilicon sources; Hydrothermal synthesis; MCM-41; porosity; Structural stability

Identification of a respiratory-type nitrate reductase and its role for survival of mycobacterium smegmatis in wayne model - Khan, Arshad; Sarkar, Dhiman (Microbial Pathogenesis, 2006)
Nitrate reductase (NR) is found to be expressed in certain mycobacterium sp. whose link with the development of persistence is yet to be resolved. The present study demonstrates the action of selective inhibitors on NR as well as in the survival of Mycobacterium smegmatis using Wayne's model. During gradual shift down to anaerobic stage in Wayne's model, conversion of nitrate to nitrite became apparent in M. smegmatis. More than 97 percent inhibition was observed for the conversion of nitrate to nitrite by azide (0.05 mM) and thiocyanate (20 mM) in both whole-cell as well as its cell-free lysate, respectively. Under identical condition, chlorate (20 mM) inhibited nitrate reduction by 67 and 10 percent, respectively. At these concentrations, neither of azide, thiocyanate nor chlorate had any significant effect on cell growth under aerobic condition. In Wayne's culture model, thiocyanate and chlorate inhibited the growth of M. smegmatis by almost 2 logs at the same concentrations whereas azide inhibited by almost 1.75 log when added at the time of inoculation. Exposure of same culture at 96 h after inoculation in Wayne's model to these inhibitors showed 1.74, 1.95 and 2.37 log inhibition of viable cells with respect to azide, thiocyanate and chlorate. These findings further indicated that NR inhibitors kill the bacilli at anaerobic stage under the experimental condition mentioned. Metronidazole (MTZ) (2 mM) and Nitrofurantoin (NIT) (0.3 mM) reduced the cell number at both stages by < 0.7log. They did not have any effect on NR. Altogether, the results clearly indicate that NR-specific inhibitors could become more promising in killing the bacilli at anaerobic stage than the available conventional drugs. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: Mycobacterium smegmatis; nitrate reductase; Wayne model

In situ optical emission spectroscopic investigations during arc plasma synthesis of iron oxide nanoparticles by thermal plasma - Banerjee, Indrani; Joshi, N. K.; Sahasrabudhe, S. N.; Kulkarni, Naveen V.; Karmakar, Soumen; Pasricha, R.; Ghorui, S.; Tak, Atul K.; Murthy, Shri P. S. S.; Bhoraskar, S. V.; Das, A. K. (IEEE Transactions on Plasma Science, 2006)
Investigations using in situ precursor spectroscopy during the growth of nanoparticles of iron oxide by thermal plasma induced gas phase condensation method have been shown to be useful for correlating the size of nanoparticles with existing plasma parameters. The relative abundance of ionized Fe species inside the plasma plume is seen to directly establish the relation between particle size, arc current, arc length, and ambient pressure of the reacting oxygen gas. The argon plasma from a transferred arc reactor is made to impinge on the anode that is allowed to vaporize and react with oxygen. The spectral line profiles of both Ar and Fe along the plasma column during the synthesis of nanoparticles have been proved to be useful in understanding the growth mechanism. Band intensities of FeO molecular states indicated the inverse relation with particle sizes that have been correlated to the two competitive processes in which energy is released, namely: 1) one involving the radiative transition and 2) the other that of the growth by coagulation. Atomic Boltzmann plots are used for estimating the temperatures of the zones, whereas particle sizes have been inferred using transmission electron microscopic measurements.
Keywords: plasma arc device; plasma-materials processing applications; spectroscopy

Ionic liquid promoted facile one-pot synthesis of 1-pyridylimidazo[1,5-a]pyridines from dipyridylketone and aryl aldehydes - Siddiqui, Shafi A.; Potewar, Taterao M.; Lahoti, Rajgopal J.; Srinivasan, Kumar V. (Synthesis-Stuttgart, 2006)
A highly efficient one-pot methodology has been developed to synthesize a class of substituted 1-pyridylimidazo[ 1,5-a]pyridines, using Bronsted acidic ionic liquid 1-butylimidazolium tetrafluoroborate, [Hbim]BF4 in excellent isolated yields in the absence of any catalyst. The methodology is characterized by simple work-up procedures along with efficient recovery and recycling of the ionic liquid, which acts as a reaction medium as well as a promoter.
Keywords: 5-a]pyridines; Aldehyde; ammonium acetate; heterocycles; imidazo[1; ionic liquids

La0.7Sr0.3MnO3 nanoparticles coated with fatty amine - Rajagopal, Rajashree; Mona, J.; Kale, Sangeeta N.; Bala, Tanushree; Pasricha, Rem; Poddar, P.; Sastry, M.; Bhagavatula L. V. Prasad; Kundaliya, Darshan C.; Ogale, S. B. (Applied Physics Letters, 2006)
We report on the synthesis of La0.7Sr0.3MnO3 (LSMO) nanoparticles having perovskite structure and particle size of the order of 30 rim. The process involves citrate-gel synthesis, size filtering, and; surface coating with a shell of octadecyl amine (ODA) using electrostatic interaction-assisted novel chemical route. Magnetic measurements show the Curie temperature of similar to 360 K establishing the desired stoichiometry and phase. Fourier transform infrared-studies bring out. that the amine group of ODA interacts with the LSMO surface. Refluidization yields uniform redispersion of the coated and dried powder. (c) 2006 American Institute of Physics.

Ligand-, copper-, and amine-free one-pot synthesis of 2-substituted indoles via Sonogashira coupling 5-endo-dig cyclization - Palimkar, Sanjay S.; Kumar, P. Harish; Lahoti, Rajgopal J.; Srinivasan, Kumar V. (Tetrahedron, 2006)
Results of the optimized conditions for the one-pot synthesis of 2-substituted indoles via palladium acetate catalyzed tandem Sonogashira coupling 5-endo-dig cyclization at room temperature under ultrasonic irradiation and standard stirred conditions are described. Electron-donating and electron-withdrawing groups present in both Coupling partners were well tolerated under these mild conditions. A copper-, ligand- and amine-free condition is an important feature of this protocol. Significant enhancement of reaction rates was observed for the reactions employing ultrasonic irradiation. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: 5-endo-dig cyclization; Indole; synthesis; Ultrasound

Liquid phase alkylation of phenol with 1-octene over large pore zeolites - Wagholikar, Smita; Mayadevi, S.; Sivasanker, S. (Applied Catalysis A-General, 2006)
A comparative study is presented of the liquid phase alkylation of phenol with 1-octene over different zeolite catalysts: H-beta (BEA(15)), H-mordenite (MOR(11)) and H-USY (FAU(15)). A wide spectrum of monoalkylated products, identified as isomers of phenyl octyl ether (O-alkylate) and octyl phenol (C-alkylate), was formed in the reaction. The reaction was studied in detail over BEA(15), such studies included the influence of process variables such as temperature, reactant mole ratio, catalyst amount and alkali metal (K) poisoning on its performance in the alkylation reaction. A kinetic analysis of the reaction over BEA(15) was also carried out assuming a second order parallel reaction mechanism. The activity of the different catalysts for the reaction followed the order: BEA(15) > FAU(15) > MOR(11). The poisoning of BEA(15) with potassium resulted in a decrease in the catalyst activity concomitant with a decrease in the number of strong acid centres in the catalyst. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: 1-octene; alkyl phenols; Alkylation; phenol; zeolites

Liquid phase oxidation of alkanes using Cu/Co-perchlorophthalocyanine immobilized MCM-41 under mild reaction conditions - Karandikar, Prashant R.; Chandwadkar, Asha J.; Agashe, M.; Ramgir, N. S.; Sivasanker, S. (Applied Catalysis A-General, 2006)
{Amino-functionalized MCM-41 (NH2-MCM-41) was used to immobilize CU/CO-Cl16PC complex, i.e. Cu/Co-AM(PS) for liquid phase oxidation of alkanes under mild reaction conditions. Higher rates of reaction and better catalytic activity values were obtained for Cu/Co-AM(PS) as compared to Cu/Co-Cl16PC grafted on (i) amino-functionalized SiO2 [
Keywords: Ceramics; Electron microscopy; electronic materials; X-ray diffraction

Low temperature hydrogenation of tetralin over supported rhodium catalysts in supercritical carbon dioxide solvent - Hiyoshi, Norihito; Mine, Eiichi; Rode, Chandrashekhar V.; Sato, Osamu; Shirai, Masayuki (Applied Catalysis A-General, 2006)
Hydrogenation of tetralin was studied over supported rhodium catalysts in supercritical carbon dioxide solvent at 333 K. The results were compared with those in an organic solvent and under neat conditions. Higher cis-decalin yield was obtained in supercritical carbon dioxide solvent than under non-supercritical conditions. It was observed that higher hydrogen concentration at the surface in supercritical carbon dioxide solvent led to fast direct hydrogenation of tetralin to cis-decalin; the flipping of the intermediate, octalin, to give trans-decalin could be prevented. (C) 2006 Elsevier B.V. All rights reserved.
Keywords: cis-decalin; Hydrogen storage; Hydrogenation; Supercritical carbon dioxide; supported rhodium catalysts; tetralin

Magnetic properties of NiCuZn ferrites synthesized by oxalate precursor method - Ghodake, S. A.; Ghodake, U. R.; Sawant, S. R.; Suryavanshi, S. S.; Bakare, P. P. (Journal of Magnetism and Magnetic Materials, 2006)
Ni-Cu-Zn ferrites have been synthesized by employing co-precipitation technique using oxalate precursors. X-ray diffractograms did not show impurity phases, indicating single-phase formation of the ferrites. The diffractograms of oxalate complex decomposed at 650 degrees C show that ferritization is complete up to 650 degrees C. Lattice parameter a (angstrom) was found to decrease with the addition of Ni2+ which is attributed to ionic sizes of Ni2+ (0.69 angstrom), which replaces Cu2+ (0.72 angstrom). From the thermogravimetric studies it is observed that the experimentally observed total mass loss (%), agrees with theoretically calculated mass loss (%) indicating maintenance of requisite stoichiometry. Initial permeability (mu(i)) shows increase when Ni2+ is added up to x = 0.15 while for (x > 0. 15), it decreases. The increase in initial permeability (mu(i)) is attributed to monotonic increase in Ms, and K-1 on addition of Ni2+. However, the microstructure and density (porosity) also influence mu(i) variations. The decrease in pi is attributable to increase of K-1. The composition with density 91.14% exhibits large mu(i) which also tends to increase with temperature up to 60 degrees C. Thus its usable range extends up to 60 degrees C. This samples has T-c near to 160 degrees C. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: initial permeability; magneticproperties; Magnetization; NiCuZn ferrites; XRD

Mesoporous molecular sieve (MCM-41)-filled sodium alginate hybrid nanocomposite membranes for pervaporation separation of water-isopropanol mixtures - Bhat, S. D.; Naidu, B. V. K.; Shanbhag, G.; Halligudi, Shivaraj B.; Sairam, M.; Aminabhavi, Tejraj M. (Separation of Purification Technology, 2006)
Sodium alginate (NaAlg) and the inesoporous molecular sieve (MCM-41)-filled NaAlg nanocomposite membranes have been prepared by solution casting and crosslinked with glutaraldehyde. Pervaporation performance of the MCM-41-filled NaAlg membranes has been tested and compared with plain NaAlg membrane for dehydrating isopropanol at 30 degrees C. In the studied feed composition range of 10-50 mass% of water, 20 mass% MCM-41-loaded NaAlg membrane gave the highest selectivity ranging between 29,991 and 3332 in the range of feed water compositions of 10-50 mass%. Flux for the plain NaAlg membrane ranged between 0.067 and 0.340 kg/(m(2)h), while for 20 mass% MCM-41-filled NaAlg membrane, flux increased to 0.110 and 0.555 kg/(m(2)h). To the best of our knowledge, this is the first study reported on the membrane forming properties of an admixed hybrid composite of a mesoporous molecular sieve (MCM-41) with NaAlg used in dehydration of isopropanol, yielding high selectivity to water at higher loadings of the molecular sieve as a filler. (c) 2005 Elsevier B.V. All rights reserved.
Keywords: flux and selectivity; nanocomposite membranes; pervaporation; sodium alginate; water-isopropanol

Metal-induced reductive ring opening of 1,2,4,5-tetrazines: Three resulting coordination alternatives, including the new non-innocent 1,2-diiminohydrazido(2-) bridging ligand system - Maji, Somnath; Sarkar, B.; Patra, S.; Fiedler, Jan; Mobin, Shaikh M.; Puranik, Vedavati G.; Kaim, Wolfgang; Lahiri, Goutam Kumar (Inorganic Chemistry, 2006)
{Reaction of 3,6-diaryl-1,2,4,5-tetrazines (aryl = R = phenyl, 2-furyl or 2-thienyl) with 2 equiv of Ru(acac)(2)(CH3-CN)(2) results in reductive tetrazine ring opening to yield diruthenium complexes [
Keywords: crystal engineering; hydrogen bonds; molecular; recocynition; Self-assembly; supramolecular chemistry

Molecular interactions between the specialist herbivore Manduca sexta (Lepidoptera, Sphingidae) and its natural host Nicotiana attenuata. VII. changes in the plant's proteome - Giri, Ashok P.; Wuensche, Hendrik; Mitra, Sirsha Sribas; Zavala, Jorge A.; Muck, Alexander; Svatos, Ales; Baldwin, Ian T. (Plant Physiology, 2006)
When Manduca sexta attacks Nicotiana attenuata, fatty acid-amino acid conjugates (FACs) in the larvae's oral secretions (OS) are introduced into feeding wounds. These FACs trigger a transcriptional response that is similar to the response induced by insect damage. Using two-dimensional gel electrophoresis, matrix-assisted laser desorption ionization-time of flight, and liquid chromatography-tandem mass spectrometry, we characterized the proteins in phenolic extracts and in a nuclear fraction of leaves elicited by larval attack, and/or in leaves wounded and treated with OS, FAC-free OS, and synthetic FACs. Phenolic extracts yielded approximately 600 protein spots, many of which were altered by elicitation, whereas nuclear protein fractions yielded approximately 100 spots, most of which were unchanged by elicitation. Reproducible elicitor-induced changes in 90 spots were characterized. In general, proteins that increased were involved in primary metabolism, defense, and transcriptional and translational regulation; those that decreased were involved in photosynthesis. Like the transcriptional defense responses, proteomic changes were strongly elicited by the FACs in OS. A semiquantitative reverse transcription-PCR approach based on peptide sequences was used to compare transcript and protein accumulation patterns for 17 candidate proteins. In six cases the patterns of elicited transcript accumulation were consistent with those of elicited protein accumulation. Functional analysis of one of the identified proteins involved in photosynthesis, RuBPCase activase, was accomplished by virus-induced gene silencing. Plants with decreased levels of RuBPCase activase protein had reduced photosynthetic rates and RuBPCase activity, and less biomass, responses consistent with those of herbivore-attacked plants. We conclude that the response of the plant's proteome to herbivore elicitation is complex, and integrated transcriptome-proteome-metabolome analysis is required to fully understand this ubiquitous ecological interaction.

NaIO4/KI/NaCl: a new reagent system for iodination of activated aromatics through in situ generation of iodine monochloride - Emmanuvel, Lourdusamy; Shukla, Ravi Kant; Sudalai, Arumugam; Gurunath, Suryavanshi; Sivaram, Swaminathan (Tetrahedron Letters, 2006)
A new reagent system consisting of NaIO4/KI/NaCl in aq AcOH has been found to be effective in iodinating a variety of activated aromatic substrates via in situ-generated iodine monochloride, to furnish iodoaromatics in excellent yields. This iodination procedure has been applied successfully for a cost-effective synthesis of 3,3'-diaminobenzidine, a key intermediate for preparing proton conducting membranes for fuel cell applications, with high yield and a purity of 99.7%. (c) 2006 Elsevier Ltd. All rights reserved.

NaIO4-mediated selective oxidation of alkylarenes and benzylic bromides/alcohols to carbonyl derivatives using water as solvent - Ali Shaikh, Tanveer Mahammad; Emmanuvel, Lourdusamy; Sudalai, Arumugam (Journal of Organic Chemistry, 2006)
A new transition-metal-free, sodium metaperiodate (NaIO4)-mediated direct oxidation of methylarenes and benzylic bromides to the corresponding aromatic carboxylic acids is described. Under the same reaction conditions, benzylic alcohols are selectively oxidized to afford the corresponding aldehydes in good yields without undergoing overoxidation. Unprecedentedly, oxidation of benzyl bromide, toluene, or benzyl alcohol with NaIO4 underwent nuclear bromination followed by oxidation to give 4-bromobenzoic acid in 60-79% yields.

Natural kaolinitic clay: a remarkable catalyst for highly regioselective chlorination of arenes with Cl-2 or SO2Cl2 - Jayachandran, B.; Phukan, P.; Daniel, Thomas; Sudalai, A. (Indian Journal of Chemistry Section B-Organic Chemistry Including Medicinal Chemistry, 2006)
Natural kaolinitic clay containing transition metals such as Fe and Ti in its lattice has been found to exhibit unusual regioselectivity in the liquid-phase chlorination of arenes with either Cl-2 or SO2Cl2 as the chlorinating agent para-Chlorinated products are predominant for most of the substrates with an exceptional case of ortho-selectivity for the chlorination of aniline.
Keywords: Aniline; chlorination; chlorine; ortho-chloroaniline; sulfuryl chloride

Nature and mode of addition of phosphate precursor in the synthesis of aluminum phosphate and its influence on methanol dehydration to dimethyl ether - Kumar, V. Siva; Padmasri, A. H.; Satyanarayana, C. V. V.; Reddy, I. Ajit Kumar; Raju, B. David; Rao, K. S. Rama (Catalysis Communications, 2006)
Four aluminum phosphate catalysts with Al/P = 1 were prepared by precipitation of mixture of aluminum nitrate and phosphate precursor (either phosphoric acid or diammonium hydrogen phosphate) with NH3 and precipitation of aluminum nitrate with NH3 followed by impregnation of phosphate precursor (either phosphoric acid or diammonium hydrogen phosphate). The catalysts were characterized, using different physico-chemical methods viz., BET-S.A., XRD, FT-IR, and NH3-TPD. Al-27 and P-31 MAS NMR spectroscopy was used to characterize selected catalysts in order to find out the presence of Al and P environments. The catalytic conversion of methanol to dimethyl ether was conducted over these catalysts in a temperature range of 448-548 K at atmospheric pressure. AIPO(4) prepared by precipitating the mixture of aluminum nitrate and (NH4)(2)HPO4 with aq. NH3 generated more number of moderate acid sites and showed higher methanol dehydration activity with 100% selectivity to DME at 548 K. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: Al-27 and P-31 MAS NMR; aluminum phosphate; dehydration; dimethyl ether; Methanol; NH3-TPD

Novel series of oligomers from 4-aminomethyl-tetrahydrofuran-2-carboxylates with 2,4-cis and 2,4-trans stereochemistry - Edwards, Alison A.; Sanjayan, Gangadharar J.; Hachisu, Shuji; Tranter, George E.; Fleet, George W. J. (Tetrahedron, 2006)
Two tetrahydrofuran-based y-amino acids [2,4-cis and 2,4-trans] were subjected to iterative peptide-coupling procedures to afford dimeric, tetrameric and hexameric carbopeptoids in good yield. These homooligomers were prepared for secondary structural study-to ascertain the conformational preference inherent in the monomer units. The L-xylo oligomers were protected with triethylsilyl ethers to increase the range of solvents suitable for structural investigation. Initial secondary structure data indicate the presence of hydrogen-bonded conformations in the L-ribo series. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: Foldamers; gamma amino acids; Peptidomimetics; sugar amino acids

Optically transparent magnetic nanocomposites based on encapsulated Fe3O4 nanoparticles in a sol-gel silica network - Thomas, Senoy; Sakthikumar, D.; Joy, Pattayil Alias; Yoshida, Yasuhiko; Anantharaman, Maliemadom R. (Nanotechnology, 2006)
Composite Fe3O4-SiO2 materials were prepared by the sol-gel method with tetraethoxysilane and aqueous-based Fe3O4 ferrofluids as precursors. The monoliths obtained were crack free and showed both optical and magnetic properties. The structural properties were determined by infrared spectroscopy, x-ray diffractometry and transmission electron microscopy. Fe3O4 particles of 20 nm size lie within the pores of the matrix without any strong Si-O-Fe bonding. The well established silica network provides effective confinement to these nanoparticles. The composites were transparent in the 600-800 nm regime and the field dependent magnetization curves suggest that the composite exhibits superparamagnetic characteristics.

Optimization of anaerobically digested distillery molasses spent wash decolorization using soil as inoculum in the absence of additional carbon and nitrogen source - Adikane, H. V.; Dange, M. N.; Selvakumari, K. (Bioresource Technology, 2006)
The aim of this study was to achieve maximum decolorization of molasses spent wash (MSW) in absence of any additional carbon or nitrogen source using soil as inoculum. Soil samples were collected from the MSW disposal site. Colored soil samples exhibited higher pH, sugar and protein as compare to less colored samples. A decolorization of 69% was obtained using 10% (w/v) soil and 12.5% (v/v) MSW after 7 days incubation. Optimized parameters including days-6 days, pH-6, MSW-12.5% and soil concentration-40%, were obtained for maximum decolorization. A decolorization of 81% was achieved using 10% soil and 12.5% MSW after 18 days incubation in absence of any media supplement. Nearly 12% reduction in decolorization activity of the soil sample was observed over a period of 12 months when stored at 6 degrees C. It could be concluded that the decolorization of MSW might be achieved using soil as inoculum without addition of chemical amendments. (c) 2005 Elsevier Ltd. All rights reserved.
Keywords: Decolorization; melanoidin; molasses spent wash (MSW); Optimization; soil

Organic dye molecules as reducing agent for the synthesis of electroactive gold nanoplates - Sharma, Jadab; Vijayamohanan, Kunjukrishna P. (Journal of Colloid and Interface Science, 2006)
Highly crystalline, hexagonal and triangular nanoplates of gold are synthesized in high yield by a new wet chemical method using multifunctional molecules. Bismarck brown R (BBR) and Bismarck brown Y (BBY). This method involves a simple approach by keeping a mixture of aqueous HAuCl(4) solution and BBR/BBY solution in presence of poly(vinyl pyrrolidone) for 24 h. These nanostructures show unprecedented electrochemical properties exhibiting Surface confinement effect. The UV-visible (UV-vis) spectrum shows certain distinct features with absorptions at 300, 400,and 650 nm extending up to the near infrared region. Selected area electron diffraction patterns of these nanoparticles show highly oriented (111) crystal facets. X-ray diffraction analysis also confirms the Predominant orientation in the (111) crystal planes with lattice constant similar to 4.07 angstrom of face-centered-cubic (fcc) gold. X-ray photoelectron (XP) and Fourier transform infrared (FTIR) spectroscopic analysis shows the presence of a fraction of reducing molecules as surface passivating agent either in the unreacted molecular state or as a mixture of reacted and unreacted product which probably undergoes charge transfer with gold nanocrystals giving absorption at similar to 300 nm. (c) 2005 Elsevier Inc. All rights reserved.
Keywords: Bismarck brown; cyclic voltammetry; gold nanoplates; poly(vinyl pyrrolidone); surface plasmon resonance

Organosilanesulfonic acid-functionalized Zr-TMS catalysts: synthesis, characterization and catalytic applications in condensation reactions - Chidambaram, M.; Venkatesan, C.; Singh, A. P. (Applied Catalysis A-General, 2006)
Organosilanesulfonic acid (-Si-R3S-R4SO3H, OSA)-functionalized mesoporous Zr-TMS (Zr-TMS-Si-R3S-R4SO3H, Zr-TMS-OSA) was synthesized either by post-synthetic modification of Zr-TMS (zirconia-based transition metal oxide mesoporous molecular sieves) with 3-mercaptopropyltrimethoxysilane (3-MPTS) and further with 1,4-butanesultone (1,4-BS) or by in situ one-pot synthesis procedure. A number of physico-chemical characterization techniques have been used to show that the organosilanesulfonic acid groups were anchored on to the walls of Zr-TMS. MCM-41-Si-R3S-R4SO3H-20 (MCM-41-OSA-20) was also prepared by post-synthesis procedure for comparison. Physico-chemical properties of in situ made A-Zr-OSA-20, Zr-TMS-SO3H-20 and MCM-41-OSA-20 were compared with Zr-TMS-OSA catalysts. The catalytic activity of the materials was tested in liquid phase condensation of aniline with p-formaldehyde to 4,4'-diaminodiphenylmethane (4,4'-DADPM). Results showed that Zr-TMS-OSA catalysts were more active than Zr-TMS-SO3H-20, MCM-41-OSA-20 and A-Zr-OSA-20 and more selective than Zr-TMS-SO3H-20 and A-Zr-OSA-20 catalysts. (C) 2006 Elsevier B.V. All rights reserved.
Keywords: Acid catalyst; condensation of aniline; mesoporous ZrO2; organic functionalization; organosilanesulfonic acid

Ossification: a new approach to immobilize metal complex catalysts - applications to carbonylation and Suzuki coupling reactions - Sarkar, Bibhas R.; Chaudhari, Raghunath V. (Journal of Catalysis, 2006)
A simple approach for immobilization of transition metal complexes is reported here based on the transformation of the complex into its intrinsically insoluble counterpart, thus generating solid molecular catalysts. This approach that we call ``ossification'' is based on a principle, in which the water-soluble analogues of the metal complexes are precipitated out from aqueous solutions as insoluble ionic ensembles having catalytically active metal-centered coordination environments and robust framework. The approach has been illustrated for I'd complex catalyzed carbonylation and Suzuki coupling reactions. ``Ossification'' was found to be an economically and environmentally attractive alternative to other exotic immobilization methodologies. (c) 2006 Elsevier Inc. All rights reserved.
Keywords: Carbonylation; Heterogeneous catalysts; Immobilization; ossification; Palladium complex; Suzuki coupling

Oxidation of ethyl benzene and diphenyl methane over ordered mesoporous M-MCM-41 (M = Ti, V, Cr): synthesis, characterization and structure-activity correlations - Jha, Ratnesh Kumar; Shylesh, S.; Bhoware, Shrikant S.; Singh, A. P. (Microporous and Mesoporous Materials, 2006)
Transition metals (M = Ti, V, Cr) were incorporated into the MCM-41 framework by surfactant-assisted direct hydrothermal (DHT) methods and were characterized in detail by XRD, N-2 adsorption-desorption, TG-DTG/DTA, SEM/TEM, DR UV-Vis, XPS and EPR. The structural regularity as well as the textural properties of the M-MCM-41 materials was confirmed by XRD, TEM and adsorption-desorption techniques. Nature of metal species and the percentage of framework as well as extra framework metal sites in the MCM-41 matrix are discussed in detail by various spectroscopic techniques. The catalytic activity as well as the selectivity of the M-MCM-41 catalysts were explored in the one-step liquid-phase oxidation reaction of ethyl benzene and diphenyl methane. Reaction data showed that the oxidation activity is more when H2O2 was used an oxidant, acetonitrile as solvent and V-MCM-41 as catalyst. However, the selectivity towards the desired keto derivatives (ethyl benzene to acetophenone and diphenyl methane to benzophenone) follows the order, Ti-MCM-41 > V-MCM-41 > Cr-MCM-41. (c) 2006 Elsevier Inc. All rights reserved.
Keywords: diphenyl methane; Ethyl benzene; MCM-41; Oxidation

Oxovanadium(IV) complex of 2-(alpha-hydroxyethyl)benzimidazole covalently bonded to chloromethylated polystyrene for oxidation of benzoin - Maurya, Mannar R.; Sikarwar, Sweta; Manikandan, Palanichamy (Applied Catalysis A-General, 2006)
Vanadyl sulphate reacts with 2-(alpha-hydroxyethyl)benzimidazole covalently bonded to chloromethylated polystyrene (PS-Hhebmz) cross-linked with 5% divinyl benzene to give PS-[VO(hebmZ)(2)]. Characterisation of the catalyst was carried out by IR, electronic and EPR spectroscopic studies, thermogravimetry, scanning electron micrographs and elemental analyses. Catalytic potential of the complex was tested for the oxidation of benzoin using tert-butyl hydroperoxide (TBHP) as an oxidant in methanol where benzil, methylbenzoate, benzoic acid and dimethylacetal were obtained as products. Various parameters such as different solvents and concentration of the substrate as well as oxidant have been taken into consideration for the maximum oxidation of the benzoin. Under optimised reaction conditions, a maximum of 98.9% conversion of the benzoin was achieved after 6 h of reaction time where selectivity of the obtained reaction products varied in the order: methylbenzoate (48.5%) > benzil (19.5%) > dimethylacetal (17.1%) > benzoic acid (11.5%). Neat complex was also prepared to compare its catalytic property with polymer-anchored one. EPR spectra of neat and polymer anchored catalyst are characteristics of V(IV) complexes with typical axial pattern and possible square pyramidal geometry. The identical EPR spectral patterns of both freshly prepared and recovered anchored catalysts indicate that the complex is stable and the coordination environment is retained at the end of the catalytic reaction. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: 2-(alpha-hydroxyethyl)benzimidazole; oxidation of benzoin; polymer-anchored complex; Polystyrene; vanadium(IV) complex

Phase evolution of NiTiO3 prepared by coprecipitation method - Murugan, A. Vadivel; Samuel, V.; Navale, S. C.; Ravi, V. (Materials Letters, 2006)
A simple coprecipitation technique was used for the preparation of NiTiO3 powders. Ammonium carbonate solution was added to a solution mixture containing stoichiometric amounts of Ni(NO3)(2) and TiOCl2 to precipitate nickel as carbonate and titanium as hydroxide under basic conditions. The precipitate was calcined at different temperatures ranging from 100 to 800 degrees C and phase evolution of NiTiO3 was investigated by X-ray diffraction (XRD) studies. It is observed that nickel titanate was formed at 750 degrees C. For comparison, NiTiO3 was also prepared by standard ceramic process. Particle size and morphology was studied by transmission electron microscopy (TEM). (c) 2005 Elsevier B.V. All fights reserved.
Keywords: Ceramics; Chemical synthesis; Electron microscopy; NiTiO3; Oxides; X-ray diffraction

Phenol tert-butylation over zirconia-supported 12-molybdophosphoric acid catalyst - Devassy, Biju M.; Shanbhag, G.V.; Halligudi, S.B. (Journal of Molecular Catalysis A-Chemical, 2006)
The alkylation of phenol with tert-butanol was investigated using zirconia-supported 12-molybdophosphoric acid (MPA) as catalyst. The catalysts with different MPA loading (5-25 wt.% calcined at 700 degrees C) and calcination temperature (15 wt.% calcined from 500 to 750 degrees C) were prepared by suspending zirconium oxyhydroxide in methanol solution of MPA followed by drying and calcination. These catalysts were characterized by X-ray diffraction and (31)p MAS NMR spectroscopy measurements. The XRD results indicated that MPA stabilizes the tetragonal phase of zirconia. (31)p MAS NMR spectra showed the presence of three types of phosphorous species, phosphomolybdate in interaction with zirconia, decomposition product of MFPA and an unidentified species. IFTIR pyridine adsorption on 15% MPA catalyst calcined at different temperatures showed the presence of both Bronsted and Lewis acidity and the catalyst calcined at 700 degrees C showed the highest relative Bronsted acidity. Under the reaction conditions of 140 degrees C, tert-butanol/phenol molar ratio of 2 and LHSV of 4 h(-1), the phenol conversion was 80.6% at 2 h (selectivity to 2-TBP 11.5%, 2,4-DTBP 55.2%, and 4-TBP 25.7%), which decreased slowly with time and at 31 h, it was 58.5% (selectivity to 2-TBP 15.2%, 2,4-DTBP 41.6%, and 4-TBP 38.4%). The major reason for the catalyst deactivation was the reduction and leaching of MPA from the catalyst surface. (c) 2005 Elsevier B.V. All rights reserved.
Keywords: 12-molybdophosphoric acid; phenol; tert-butylation; Zirconia

Photo-bio-degradability of agro waste and ethylene-propylene copolymers composites under abiotic and biotic environments - Kumar, A. Pratheep; Pandey, Jitendra K.; Kumar, Bijendra; Singh, R. P. (Journal of Polymers and the Environment, 2006)
Composites were prepared by two methods, (i) graft copolymerization (GFC) of isotactic polypropylene (PP) with maliec anhydride, (MAH) followed by esterification with coir fiber and (ii) by direct reactive mixing (DFC) of polypropylene (PP) and ethylene-propylene (EP) copolymers with MAH and peroxide with coir fiber. These composites, after molding in films (5 x 5 cm, - 100 mu m thickness) were examined for susceptibility to biological attack by measuring the percentage weight loss in compost upto 6 months, periodically, and fungal colonization on surface of the samples, when kept as sole carbon source for the growth of Aspergillus niger in culture medium upto 40 days. Photodegradation was evaluated by monitoring the variations in FT-IR spectrum and crack formation after successive treatment with UV light (>= 290 nm) for 0, 20, 50 and 100 h at 60 C in the presence of air. Specimens of virgin PP were taken as a reference during all period of photo and biodegradation studies. Significant changes were observed depending on the preparation methods during photodegradation and biodisintegration of composites. DFCs samples were disintegrated faster than GFCs during the composting whereas, in culture, GFCs were covered highly in well uniform way by fungi. It was observed that photo-oxidative ageing directly enhanced the biodegradability of composites as the increase in fungal growth rate and decrease in weight during composting were found. It was concluded that extent of compatibilization had a profound effect on photo-oxidation and biodisintegration of composite material; consequently ester bonds were main units during fungal consumption. Composition of monomers in copolymers was also showing significant effect on the degradability which decreased with increasing content of ethylene in ethylene-propylene (EP) copolymers.
Keywords: Biodegradation; biodisintegration and composting; composites; ethylene-propylene copolymers; photo-degradation

Photoluminescence studies of Eu3+ doped Y2O3 nanophosphor prepared by microwave hydrothermal method - Murugan, A. Vadivel; Viswanath, Annamraju Kasi; Ravi, V.; Kakade, Bhalchandra A.; Saaminathan, V. (Applied Physics Letters, 2006)
In this letter, the authors report the photoluminescence studies of Eu3+ doped Y2O3 nanorods, which have been synthesized by rapid microwave hydrothermal route within 6 min. The nanostructured Eu3+ doped Y2O3 is characterized by x-ray diffraction, transmission electron microscopy, and photoluminescence. The emission spectrum shows transitions from the excited 5D(0) state to F-7(J) (J=0,1,2,3,4) levels of the Eu3+ ion. The most intense peak around 612 nm is due to the D-5(0)-> F-7(2) transition, expected from the Judd-Ofelt selection rules [B. R. Judd, Phys. Rev. 127, 750 (1962); G. S. Ofelt, J. Chem. Phys. 37, 511 (1962)]. Photoluminescence measurements demonstrated that the nanocrystalline Eu3+:Y2O3 phase shows higher photoluminescence intensity. (c) 2006 American Institute of Physics.

Photooxidation of vulcanized EPDM/montmorillonite nanocomposites - Morlat-Therias, Sandrine; Fanton, Elisabeth; Tomer, Namrata S.; Rana, Sravendra; Singh, R. P.; Gardette, Jean Luc (Polymer Degradation and Stability, 2006)
The photooxidation of a vulcanized ethylene-propylene-diene monomer (EPDM)/montmorillonite nanocomposite as well as EPDM/nanocomposite with stabilizers was studied under accelerated UV-light irradiation (lambda >= 300 nm, 60 degrees C) for different times. The development of functional groups during oxidation was monitored by infrared spectroscopy. Photodegradation of the neat polymer and composites took place and the increases of absorbance in hydroxyl and carbonyl groups with irradiation times and also the decreases of the EPDM unsaturations were measured. The data indicated that the photooxidation products were not changed in the presence of the nanofiller. However, the presence of MMt was observed to dramatically enhance the rate of photooxidation of EPDM with a shortening of the oxidation induction time, leading to a decrease of the durability of the nanocomposites. On the other hand, it was observed that addition of stabilizers, either Tinuvin P or 2-mercaptobenzimidazole, was efficient in inhibiting the degradative effect of MMt. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: EPDM; Nanocomposite; photooxidation rate; stabilization

Physical manipulation of biological and chemical syntheses for nanoparticle shape and size control - Ogale, Satishchandra B.; Ahmad, Absar; Pasricha, R.; Dhas, Vivek V.; Syed, A. (Applied Physics Letters, 2006)
A nanosynthesis scheme is demonstrated which renders excellent control of nanoparticle shape, size, and dispersity in a solution based synthesis process. The scheme, termed as percolative microcavity synthesis, involves the use of a granular medium with percolative microcavities which facilitate nearly similar grain size/shape dependent reaction zones limiting intrinsic growth inhomogeneities, enabling particle size/shape control. The viability of the process is demonstrated for the synthesis of gold nanoparticles by a plant extract based biological method as well as a chemical method. (c) 2006 American Institute of Physics.

Poly(High Internal Phase Emulsion) of 2-EHA, 2-EHMA and EGDA with naturally occurring phenolic compounds", paper presented at international conference on ?polymers for advanced technology - Ingavle, Ganesh C.; Shaikh, A. A.; Bhongale, Sunil Sitaram; Scaria, S.; Chavan, Nayaku; Qureshi, Mohammed; Ponrathnam, Surendra (Polymers for Advanced Technology, 2006)

Poly(o-toluidine) coatings on copper: electrochemical synthesis from aqueous media - Shinde, V.; Mandale, A. B.; Patil, K. R.; Gaikwad, A. B.; Patil, P. P. (Surface & Coating Technology, 2006)
Poly(o-toluidine) (POT) coatings were synthesized on copper (Cu) by electrochemical polymerization of o-toluidine using aqueous sodium oxalate solution as supporting electrolyte. The resulting coatings were uniform, compact and strongly adherent to the Cu substrate. These coatings were characterized by using cyclic voltammetry, UV-visible absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) measurements and X-ray photoelectron spectroscopy (XPS). The results of these studies reveal that the sodium oxalate is suitable supporting electrolyte for the electrochemical polymerization of o-toluidine on Cu substrate. It is found that the electrochemical polymerization of o-toluidine takes place after the passivation of the Cu substrate via formation of copper oxalate (CuC2O4, H2O) layer, which is confirmed by XRD and XPS. The optical absorption spectroscopy study reveals the exclusive formation of the pernigraniline base (PB) form of POT. (c) 2005 Elsevier B.V. All rights reserved.
Keywords: Conducting polymer coatings; Copper; Corrosion resistant coatings; cyclic voltammetry; poly(o-toluidine) coatings

Potassium phosphate or silica sulfuric acid catalyzed conjugate addition of thiols to alpha,beta-unsaturated ketones at room temperature under solvent-free conditions - Pore, D. M.; Soudagar, M. S.; Desai, Uday V.; Thopate, T. S.; Wadagaonkar, P. P. (Tetrahedron Letters, 2006)
Potassium phosphate and silica sulfuric acid have been found to be useful and highly efficient catalysts for conjugate addition of thiols to alpha,beta-unsaturated ketones under solvent-free conditions, at room temperature. Silica sulfuric acid (SSA) was found to be suitable for electron-deficient enones while potassium phosphate was found to effect thia-Michael addition with both, electron-deficient as well as electron-rich conjugated ketones. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: alpha; beta-unsaturated ketones; chalcones; conjugated enones; Michael addition; Potassium phosphate; silica sulfuric acid; thiols

Preparation and characterization of novel hybrid of chitosan-g-lactic acid and montmorillonite - Depan, Dilip; Kumar, Annamalai Pratheep; Singh, Raj Pal (Journal of Biomedical Materials Research Part A, 2006)
The utilization of biopolymers and the development of organic-inorganic hybrids are ever increasing interest of material science researchers around the globe for various applications. The present attempt is intended to prepare nanocomposites of lactic acid grafted chitosan and layered silicates. Nanocomposites were prepared by dissolving chitosan and dispersing sodium montmorillonite in aqueous solution of L-lactic acid with subsequent heating and film casting. They were characterized by conventional techniques such as Fourier transform infrared spectroscopy, X-ray diffractometry, thermogravimetric analysis, energy dispersive X-ray spectroscopy, and elemental analysis. The results from polar optical and transmission electron microscopic measurements are also discussed. Sorption behavior of samples has been followed by measuring swelling degree and contact angle. The films have shown enhanced hydrophilicity when compared with polylactic acid (PLA). Issues on the interactions of polycationic chitosan with clay are also discussed. It is observed that nanocomposites are exhibiting better thermal and physical properties than neat chitosang-LA and PLA. (c) 2006 Wiley Periodicals, Inc.
Keywords: Chitosan; contact angle; graft copolymerization; Nanocomposites; polylactic acid; water absorption

Preparation and characterization of urea-formaldehyde-pepsin bioconjugate: a new biocatalyst system - Vinod, V. P.; Shinde, Sudhirkumar; D'Britto, Virginia; Shukla, P. G.; Rao, Mala (Biotechnology Progress, 2006)
This study describes the synthesis of urea formaldehyde (UF) microspheres by a dispersion polycondensation polymerization method. These microspheres with proper F/U molar ratio can provide highly reactive groups, capable of further condensation with the amino acid residues of enzyme/proteins. Presence of methylols groups in UF microspheres was confirmed by C-13 NMR study. Pepsin, a proteolytic enzyme, was immobilized on the UF microspheres to form bioconjugate system. As compared to the free enzyme in solution, the pepsin in the bioconjugate system exhibited significantly enhanced pH and temperature stability. The urea-formaldehydepepsin bioconjugate system also exhibited excellent proteolytic activity over eight successive reuse cycles with more than 50% of initial activity. A highlight of this new biocatalyst is the ease with which separation of this biocatalyst from the reaction medium may be achieved by mild centrifugation.

Preparation and performance evaluation of EPDM nanocomposites under accelerated weathering - Rana, Sravendra; Tevtia, Amit K.; Kumar, Bijendra; Singh, R. P. (Journal of Thermoplastic Composite Materials, 2006)
The degradability of ethylene propylene diene monomer (EPDM) nanocomposites, prepared from organically modified montmorillonite (CMMT), is studied under accelerated UV irradiation (lambda >= 290 nm) for different time intervals. The development of functional groups during degradation is monitored by FT-IR spectroscopy whereas, surface changes are studied by scanning electron microscopy (SEM). The effect of clay modifier and clay concentration on the degradability are studied. The degradation of neat polymer and composites taking place traditionally and an increase in carbonyl and hydroxyl groups are observed with irradiation time. Neat EPDM is found to be less degradable than nanocomposites. Degradation products, as seen by FT-IR in nanocomposites are found to be the same as in neat polymer but are generated at a faster rate. According to the experimental results, one can define that both ammonium ion and neat montmorillonite (MMT) accelerate the photo-oxidation of EPDM.
Keywords: carbonyl index; Degradation; EPDM; layered silicates; Nanocomposites; photooxidation

Rapid molecular identification of freshly squeezed and reconstituted orange juice - Ng, C. C.; Chang, C. C.; Wu, I. C.; Kotwal, S.; Shyu, Y. T. (International Journal of Food Science and Technology, 2006)
This work presents a rapid and accurate molecular approach in the identification of freshly squeezed and reconstituted orange juice. Primers were designed based on the 18S and internal transcribed spacer (ITS) region. The findings indicated that self-made freshly squeezed orange juice heated to 80 degrees C for 30 s caused damage to DNA integrity, thus failing in amplification by primer 18S-ITSe, which gives a polymerase chain reaction product of 2081 bp, whereas primer 18S-ITSf, fragment length 2421 bp, could only be seen in heating conditions less stringent than 70 degrees C, 15 s. This new DNA integrity-dependent method has potential applications in identifying adulteration of freshly or processed orange juice.
Keywords: adulteration; citrus; DNA degradation; molecular detection; reconstituted juice

Remarkably rapid regioselective synthesis of beta-enaminones using silica chloride in a heterogeneous as well as an ionic liquid in a homogeneous medium at room temperature - Gholap, Atul R.; Chakor, N. S.; Daniel, Thomas; Lahoti, Rajgopal J.; Srinivasan, K. V. (Journal of Molecular Catalysis A-Chemical, 2006)
{Silica chloride as a heterogeneous catalyst has been used for the regioselective synthesis of P-amino-a,P unsaturated esters and ketones. Similar regioselective synthesis was also performed using an ionic liquid 1-n-butyl imidazolium tetrafluoroborate [
Keywords: direct oxidation of H-2 to H2O2; H2O2 decomposition; H2O2 hydrogenation; Promoting action of chloride or bromide anions; supported Pd catalysts

Re-tooling Benson's group additivity method for estimation of the enthalpy of formation of free radicals: C/H and C/H/O groups - Bhattacharya, Arijit; Shivalkar, Sagar (Journal of Chemical and Engineering Data, 2006)
Enthalpy of formation of free radicals is often required for the discrimination of reaction mechanisms (for complex processes such as combustion, hydrocarbon oxidation, or decomposition of peroxides and hydroperoxides) involving both molecular species and free radicals. Despite the expanding availability of the experimental measurements, the database for the enthalpy of formation of radicals is still not comprehensive. One of the simplest, efficient, and reliable methods for estimating the quantity for organic radicals from their molecular structure is the group-additivity method due to Benson and co-workers. Perusal of the literature shows that the group-additivity values (GAV) for many radical groups have remained either undetermined or obtained by assignment to the corresponding molecular groups without justification. In this paper, we devise simple methodologies to evaluate GAVs for a number of new oxygen-containing radical groups and re-estimate several alkyl and oxygen-containing radical groups using experimental data on the radical enthalpy of formation. The validity of these GAVs has been established by comparing the predicted enthalpies with experimental data. Finally, some of these updated GAVs were used in estimating the enthalpy change associated with the typical elementary steps in a peroxide decomposition reaction.

Reverse microemulsion mediated sol-gel synthesis of lithium silicate nanoparticles under ambient conditions: Scope for CO2 sequestration - Khomane, Ramdas B.; Sharma, B. K.; Saha, S.; Kulkarni, B. D. (Chemical Engineering Science, 2006)
We report on the synthesis of nanocrystalline lithium silicate by coupling of sol-gel method in reverse microemulsion. The sample calcined at 800 degrees C gives pure phase lithium metasilicate nanocrystallites. X-ray diffraction and transmission electron microscopy confirmed the formation of nanocrystalline lithium silicate particles with a narrow size distribution. The nanoparticle prepared in the microemulsion shows enhanced CO2 sorption capacity and shorter retention times at higher temperature (similar to 131 ml/g at STP at 610 degrees C which are better than the best known results. (c) 2005 Elsevier Ltd. All rights reserved.
Keywords: Adsorption; Carbon dioxide; Microemulsion; particle; separations; sol-gel; surfactant

Ring closing metathesis approach to the indole alkaloid mitralactonine - Chavan, Subhash P.; Sharma, Pallavi; Sivappa, R.; Kalkote, Uttam R. (Tetrahedron Letters, 2006)
An efficient utilisation of RCM leading to a convenient synthesis of a pentacyclic indole alkaloid is described. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: corynanthe type alkaloid; Dihydroxylation; mitralactonine; RCM; Swern oxidation

Ring hydrogenation of naphthalene and 1-naphthol over supported metal catalysts in supercritical carbon dioxide solvent - Shirai, M.; Rode, C. V.; Mine, Eiichi; Sasaki, A.; Sato, O.; Hiyoshi, Norihito (Catalysis Today, 2006)
Catalytic ring hydrogenations of naphthalene and 1-naphthol were studied over several supported metal catalysts in supercritical carbon dioxide solvent at low temperature. Higher concentration of hydrogen in supercritical carbon dioxide and lower reaction temperature were responsible for higher catalyst activity and selectivities to the desired partial ring hydrogenated products as compared with those observed in organic solvent for the same catalyst. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: 1-naphthol; Hydrogenation; Naphthalene; Supercritical carbon dioxide; supported metal catalyst

Role of halide ions and temperature on the morphology of biologically synthesized gold nanotriangles - Rai, A.; Singh, A.; Ahmad, Absar; Sastry, M. (Langmuir, 2006)
{In this paper, we demonstrate the effect of halide ions on the formation of biogenically prepared gold nanotriangles using the leaf extract of lemongrass (Cymbopogonflextiosus) plant. We have also studied the effect of halide ions on the morphology of biogenic nanotriangles. It has been shown that iodide ions have a greater propensity to transform flat gold nanotriangles into circular disklike structures as compared to other halide ions. The study also suggests that the presence of Cl- ions during the synthesis promotes the growth of nanotriangles, whereas the presence of I- ions distorts the nanotriangle morphology and induces the formation of aggregated spherical nanoparticles. The change in the morphology of gold nanotriangles has been explained in terms of the ability of the halide ions to stabilize or inhibit the formation of (I 11) faces to form [
Keywords: DME steam reforming; fuel cells; Hydrogen; Mixed oxides; supported Ga2O3; XPS

Room-temperature biosynthesis of ferroelectric barium titanate nanoparticles - Bansal, Vipul; Poddar, Pankaj; Ahmad, Absar; Sastry, Murali (Journal of the American Chemical Society, 2006)
The syntheses of inorganic materials by biological systems is characterized by processes that occur close to ambient temperatures, pressures, and neutral pH, as is exemplified by biosilicification and biomineralization processes in nature. Conversely, laboratory-based syntheses of oxide materials often require extremes of temperature and pressure. We have shown here the extracellular, room-temperature biosynthesis of 4-5 nm ternary oxide nanoparticles such as barium titanate (BT) using a fungus-mediated approach. The tetragonality as well as a lowered Curie transition temperature in sub-10 nm particles was established, and the ferroelectricity in these particles was shown using Kelvin probe microscopy.

Selective hydrogenation of naphthols to tetralones over supported palladium catalysts in supercritical carbon dioxide solvent - Mine, Eiichi; Hiyoshi, Norihito; Sato, Osamu; Rode, Chandrashekhar V.; Shirai, Masayuki (Chemistry Letters, 2006)
Naphthols were selectively hydrogenated to the corresponding tetralones over supported palladium metal catalysts in super-critical carbon dioxide solvent.

Short and practical enantioselective synthesis of linezolid and eperezolid via proline-catalyzed asymmetric alpha-aminooxylation - Narina, Srinivasarao V.; Sudalai, Arumugam (Tetrahedron Letters, 2006)
An efficient enantioselective synthesis of the antibacterials, linezolid (U-100766), and eperezolid (U-100592) using D-proline-catalyzed asymmetric alpha-aminooxylation of aldehydes as the key step is described here. This is the first report on the enantioselective synthesis of linezolid and eperezolid using asymmetric catalysis. (c) 2006 Elsevier Ltd. All rights reserved.

Short enantioselective synthesis of (-)-chloramphenicol and (+)-thiamphenicol using tethered aminohydroxylation - George, Shyla; Narina, Srinivasarao V.; Sudalai, Arumugarn (Tetrahedron, 2006)
An efficient enantioselective synthesis of (-)-chloramphenicol (1) and (+)-thiamphenicol (2) is described. These antibiotics have been synthesized from commercially available 4-nitrobenzaldehyde and 4-(methylthio)benzaldehyde, respectively, using tethered amino-hydroxylation and Sharpless asymmetric epoxidation as the chirality inducing steps. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: asymmetric epoxidation; Asymmetric synthesis; Kinetic resolution; Tethered aminohydroxylation

Short enantioselective synthesis of the antiepileptic agent, levetiracetam based on proline-catalyzed asymmetric alpha-aminooxylation - Kotkar, Shriram P.; Sudalai, Arumugam (Tetrahedron Letters, 2006)
An efficient enantioselective synthesis of a new antiepileptic drug, levetiracetam is described, in high optical purity (> 99.5% ee), using proline-catalyzed alpha-aminooxylation of n-butyraldehyde as the key step. (c) 2006 Elsevier Ltd. All rights reserved.

Silica-supported bis(imino)pyridyl iron(II) catalyst: nature of the support-catalyst interactions - Ray, Saptarshi; Sivaram, Swaminathan (Polymer International, 2006)
Ethylene polymerizations were performed using silica-supported 2,6-bis[1-(2,6-diisopropylphenylimino) ethyl] pyridine iron(II) dichloride with methylaluminoxane (MAO) as co-catalyst. Silica was calcined at 600, 400 and 200 degrees C under vacuum for 8 h. The effect of calcination temperature of silica on the polymerization activity and the properties of the polymers obtained were examined. Catalyst-support interactions were examined by both a chemical method and XPS. It was observed that upon supporting the catalyst on the surface of silica, there is an increase in the binding energy of the metal center. However, no change in the metal binding energy was observed on supporting the catalyst to silica calcined at different temperatures. Ethylene polymerizations were performed using MAO as co-catalyst. Catalysts were also prepared by first pretreating silica with NIAO, followed by addition of the Fe(II) catalyst and contacting a complex of Fe(II) catalyst-MAO with silica previously calcined at 400 degrees C for 8 h. The results indicate that there is no chemical bonding between the support and the catalyst. (C). 2006 Society of Chemical Industry.
Keywords: bis(imino) pyridyl iron(II) complex; Polyethylene; silica; supported catalyst; XPS

Sites for CO2 activation over amine-functionalized mesoporous Ti(Al)-SBA-15 catalysts - Srivastava, R.; Srinivas, D.; Ratnasamy, P. (Microporous and Mesoporous Materials, 2006)
{Activation of CO and its utilization in the synthesis of chloropropene and styrene carbonates over functionalized, mesoporous SBA-15 solids, have been investigated. The surface basicity of SBA-15 was modified with nitrogen-based organic molecules of varying basicity viz., alkyl amines (-NH2), adenine (Ade), imidazole (Im) and guanine (Gua). The surface of SBA-15 was also functionalized with Ti4+ and Al3+ species. The acid-base properties of these modified SBA-15 materials were investigated by temperature-programmed desorption (TPD) and diffuse-reflectance infrared Fourier transform (DRIFT) spectroscopy. NH3 and pyridine were used as probe molecules for acid sites, while CO, was used to characterize the basic sites. CO was activated at the basic amine sites forming surface carbamate species (IR peaks: 1609 and 1446 cm(-1)). The latter reacted further with epoxides adsorbed on the acid sites forming cyclic carbonates. A correlation between the intensity of the IR peak at 1609 cm(-1) and cyclic carbonate yield has been observed. The cyclic carbonate yields were higher when both the acid and base functionalities were present on the surface. The Ti- and Al-SBA-15 functionalized with adenine exhibited the highest catalytic activity and selectivity. There is an optimal dependence (''
Keywords: aromatization; Ga-based zeolites; propane; Si/Al ratio; Si/Ga ratio; zeolitic factors

Stabilization of gamma-sterilized biomedical polyolefins by synergistic mixtures of oligomeric stabilizers - Alariqi, Sameh A. S.; Kumar, A. Pratheep; Rao, B. S. M.; Tevtia, Amit K.; Singh, R. P. (Polymer Degradation and Stability, 2006)
The stabilization of polyolefins against gamma-sterilization has been studied with single or binary additive system. The present attempt is to utilize synergistic mixtures of stabilizers which are approved for food contact applications. Ethylene-propylene (EP) copolymer has been melt-mixed with hindered amine stabilizers (HAS), phenolic antioxidants and organo-phosphites (hydroperoxide decomposer). Samples were sterilized with different doses of gamma-radiation. Stabilization was characterized in terms of changes in the functional groups (oxidation products), tensile properties, yellowing and surface morphology by FTIR spectroscopy, Instron, colorimetry (reflectance) and scanning electron microscopy (SEM), respectively. Results were discussed by comparing the stabilizing efficiency of mixtures with and without phenol system. Among phenol containing systems, where we mostly observe discoloration due to the oxidation of hindered phenol and the combination of secondary HAS, tertiary HAS, organo-phosphite and hindered phenol exhibited improved stabilization efficiency than single or binary additive systems. The mixture of secondary HAS and tertiary HAS, has shown antagonistic effect of stabilization whereas their combination with organo-phosphite has exhibited synergistic effect of stabilization even at higher doses of gamma-sterilization. The effects have been explained through the interaction between the stabilizers. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: Antioxidants; discoloration; ethylene-propylene copolymer; gamma-sterilization; stabilization; tensile properties

Stereoselective syntheses of unnatural steroidal C(20R) aldehydes by ionic hydrogenation of C-20 tertiary alcohols - Shingate, Bapurao B.; Hazra, Braja G.; Pore, Vandana S.; Gonnade, Rajesh G.; Bhadbhade, Mohan M. (Tetrahedron Letters, 2006)
Syntheses of three unnatural steroidal C(20R) aldehydes have been realised from 16-dehydropregnenol one acetate. The salient feature of the synthesis is the ionic hydrogenation of C-20 tertiary alcohols leading to the formation of the C(20R) unnatural isomer with complete stereoselectivity. Oxidative hydrolysis of the dithiane moiety furnished the C(20R) aldehydes. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: 1; 3-dithiane; ionic hydrogenation; oxidative hydrolysis; stereoselective synthesis; unnatural C-20 aldehydes

Stereoselective synthesis of the polyketide chain of nagahamide A - Mohapatra, Debendra K.; Chaudhuri, Siddhartha Ray; Sahoo, Gokarneswar; Gurjar, Mukund K. (Tetrahedron-Asymmetry, 2006)
A carbohydrate based approach for the enantioselective synthesis of the polyketide acid unit present in nagahamide A has been reported. Reductive ring opening of a chiral cyclopropane ketone group to enantioselectively install the methyl and propyl groups, is a salient feature of this synthesis. (c) 2006 Elsevier Ltd. All rights reserved.

Structural and active site modification studies implicate Glu, Trp and Arg in the activity of xylanase from alkalophilic Bacillus sp (NCL 87-6-10) - Balakrishnan, H.; Satyanarayana, L.; Gaikwad, S. M.; Suresh, C. G. (Enzyme and Microbial Technology, 2006)
Structural studies and residue modification using group specific reagents were used to ascertain the role of different functional groups in xylanase from alkalophilic Bacillus sp. (NCL 87-6-10). Treatment with N-bromosuccinimide resulted in fast enzyme inactivation. Reaction with Woodward's reagent K resulted in initial fast followed by slower inactivation. In both cases enzyme was protected against inactivation by the substrate, xylan. The reaction of the enzyme with phenylglyoxal has revealed one essential arginine residue at the active site. The three-dimensional structural analysis of the xylanase at 2.8 angstrom resolution also implicates involvement of Trp, and Arg residues and carboxylate groups in the binding of substrate and in the catalysis of xylanase. (c) 2005 Published by Elsevier Inc.
Keywords: active-site residues; alkaline xylanase; Chemical modification; three-dimensional structure

Structural and functional analysis of a conjugated bile salt hydrolase from Bifidobacterium longum reveals an evolutionary relationship with penicillin V acylase - Kumar, R. Suresh; Brannigan, James A.; Prabhune, Asmita; Pundle, Archana V.; Dodson, Guy G.; Dodson, Eleanor J.; Suresh, C. G. (Journal of Biological Chemistry, 2006)
Bile salt hydrolase (BSH) is an enzyme produced by the intestinal microflora that catalyzes the deconjugation of glycine- or taurine-linked bile salts. The crystal structure of BSH reported here from Bifidobacterium longum reveals that it is a member of N-terminal nucleophil hydrolase structural superfamily possessing the characteristic alpha beta beta alpha tetra-lamellar tertiary structure arrangement. Site-directed mutagenesis of the catalytic nucleophil residue, however, shows that it has no role in zymogen processing into its corresponding active form. Substrate specificity was studied using Michaelis-Menten and inhibition kinetics and fluorescence spectroscopy. These data were compared with the specificity profile of BSH from Clostridium perfrigens and pencillin V acylase from Bacillus sphaericus, for both of which the three-dimensional structures are available. Comparative analysis shows a gradation in activity toward common substrates, throwing light on a possible common route toward the evolution of pencillin V acylase and BSH.

Subtle crossover from C-H center dot center dot center dot O to S=O center dot center dot center dot C=O short contacts in the association of diastereomers of 2,4(6)-di-O-benzoyl-6(4)-O-[(1S)-10-camphorsulfonyl]-myo-inositol 1,3,5-orthoformate upon format - Manoj, Kochunnoonny; Gonnade, Rajesh G.; Bhadbhade, Mohan M.; Shashidhar, Mysore S. (Crystal Growth & Design, 2006)
Diastereomers of 2,4(6)- di-O-benzoyl-6(4)-O-[(1S)-10-camphorsulfonyl]-myo-inositol 1,3,5-orthoformate associate via weak interactions to form ``head-to-head'' dimers in their crystals. Molecular association through C-H center dot center dot center dot O short contacts do not leave any void for the guest inclusion, while association through S=O center dot center dot center dot C=O bridging produces pseudopolymorphs. Three crystalline modifications are observed for the title compound: form I, monoclinic P2(1), without any guest solvent, and solvated forms II and III, that belong to monoclinic space groups P2(1) and C2, respectively. A majority of solvates, which include pyridine, dichloromethane, benzene, tetrahydrofuran, and cyclohexanone as guests, belong to form III. All these guests have 2-fold symmetry axes ( C2) with their electron count within 40-62 electrons; guest selectivity experiments indicate that planar aromatic guests ( pyridine, benzene) bind better to the host molecules as compared to nonplanar guests ( dioxane, cyclohexanone). The molecular packing that is created thorough channels in the crystal ( avoiding interpenetration of the layers) are of interest because of their potential application in molecular separation by forming selective inclusions. The diastereomeric association via S=O center dot center dot center dot C=O dipolar short contacts, a consistent feature observed in all the solvates, is thought to have relevance in the binding of sulfonyl drugs to the C=O moieties of the receptor proteins.

Supramolecular self-assembled ruthenium-polypyridyl framework encapsulating discrete water cluster - Deshpande, Megha S.; Kumbhar, A. S.; Puranik, Vedavati G.; Selvaraj, K. (Crystal Growth & Design, 2006)
Keywords: 4; 4 `-dimethoxydiphenylmethane; benzylsulfonic acid; Condensation of anisole; p-formaldehyde; Zr-TMS-BSA

Syntheses of polycarbonate and polyurethane precursors utilizing CO2 over highly efficient, solid as-synthesized MCM-41 catalyst - Srivastava, R.; Srinivas, D.; Ratnasamy, P. (Tetrahedron Letters, 2006)
As-synthesized MCM-41 was used as a reusable, heterogeneous catalyst for the eco-friendly synthesis of cyclic carbonate precursors of polycarbonates via a cycloaddition reaction of CO2 with epoxides. This catalyst is also efficient for the synthesis of alkyl and aryl carbamate precursors of polyurethanes via the reaction of amines, CO2 and alkyl halides. Both these reactions were carried out under mild conditions and without using any solvent or co-catalyst. CO2 is utilized as a raw material replacement for toxic phosgene in the conventional synthesis of these chemicals. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: carbamates; carbon dioxide utilization; CO2 fixation; cyclic carbonates; eco-friendly processes; MCM-41; polycarbonates; polyurethanes

Synthesis and characterization of cholesteric thermotropic liquid crystalline polyesters - Jadhav, Sushilkumar A.; Chougule, Rahul R.; Shinde, Yogesh A.; Chavan, Nayaku (Journal of Applied Polymer Science, 2006)
Cholesteric liquid crystalline polyesters were successfully synthesized from isosorbide, methyl hydroquinone, and isophthaloyl chloride. Homo/copolyesters were synthesized by the solution polycondensation method, for which a mild organic base such as pyridine was employed. Inherent viscosities of polyesters P-3-P-5 were in the range of 0.31-0.39 dL/g at 25 degrees C in chloroform, and polyesters P-1 and P-2 were insoluble in chloroform. Homo/copolyesters based on isosorbide, methyl hydroquinone, and isophthalic acid had thermal stability at more than 300 degrees C on the basis of 10% weight loss. The thermotropic liquid crystalline properties were examined by differential scanning calorimetry and polarizing optical microscopy. Wide-angle X-ray diffraction study demonstrated that polyesters P-1, P-2, and P-3 were semicrystalline, whereas the degree of crystallinity of polyesters P-4 and P-5 was less than 5%. Copolyester P-4 showed formation of a yellow iridescent streak at 209 degrees C on heating and development of a Grand-jean texture at 270 degrees C on heating. These are typical textures of the cholesteric liquid crystalline phase. (c) 2006 Wiley Periodicals, Inc.
Keywords: cholesteric liquid crystalline polymers (ChLCP); Differential scanning calorimetry (DSC); optical microscopy; solution polycondensation; Thermogravimetric analysis (TGA); viscosity

Synthesis and characterization of corrosion protective poly(2,5-dimethylaniline) coatings on copper - Shinde, Vandana; Gaikwad, A. B.; Patil, P. P. (Applied Surface Science, 2006)
Poly(2,5-dimethylaniline) coatings were synthesized on copper (Cu) by electrochemical polymerization of 2,5-dimethylaniline in aqueous salicylate solution by using cyclic voltammetry. The characterization of these coatings was carried out by cyclic voltammetry, UV-visible absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The results of these characterizations indicate that the aqueous salicylate solution is a suitable medium for the electrochemical polymerization of 2,5-dimethylaniline to generate strongly adherent and smooth poly (2,5-dimethylaniline) coatings on Cu substrates. The performance of poly(2,5-dimethylaniline) as protective coating against corrosion of Cu in aqueous 3% NaCl was assessed by the potentiodynamic polarization technique. The results of the potentiodynamic polarization demonstrate that the poly(2,5-dimethylaniline) coating has ability to protect the Cu against corrosion. The corrosion potential was about 0.078 V versus SCE more positive in aqueous 3% NaCl for the poly(2,5-dimethylaniline) coated Cu than that of uncoated Cu and reduces the corrosion rate of Cu almost by a factor of 31. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: 5-dimethylaniline) coatings; conducting polymers; Copper; Corrosion resistant coatings; cyclic voltammetry; Electrochemical polymerization; Poly(2

Synthesis and characterization of TAPO-31 molecular sieves using tripropylamine template - Venkatathri, N.; Shetty, V. N. (Catalysis Communications, 2006)
TAPO-31 was synthesized hydrothermally using a novel template tri-n-propylamine for the first time. C and N analysis shows the butanol from titanium tetrabutoxide plays an important role in the synthesis. The incorporation of titanium into framework of phosphorous and both aluminiurn and phosphorous sites was suggested from elemental analysis. Isomorphous substitution of titanium (III) in AlPO framework was confirmed from ESR and (31)p MASNMR spectra. UV-Vis and XPS spectra revealed a partial oxidation of framework titanium (III) into titanium (IV) in the calcined TAPO-31 and thus the presence of redox centers in the products. The higher titanium content (Al/Ti = 10) TAPO-31 sample shows higher activity for phenol hydroxylation compared to lower titanium content (Al/Ti = 20) and Titanium impregnated AIPO(4)-31. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: ESR; FT-IR; MASNMR; SEM; TAPO-31; TG/DTA; tripropylamine; UV-Vis; XPS; XRD

Synthesis and utility of new amine/nucleobase addition products of allenylphosphonates - Swamy, K. C. Kumara; Balaraman, Ekambaram; Kumar, N. Satish (Tetrahedron, 2006)
In the reaction of allenylphosphonates with amines/nucleobases, depending on the amine and the allenylphosphonate, either Z- or E-vinylphosphonate or allylphosphonate as a single isomer with a β-amino functionality was isolated. A simple route to phosphonates with a β-NH2 group is developed by direct reaction with ammonia. In reactions with adenine, three different modes of reaction, with one of them involving an unusual cyclisation, are observed. The utility of (enamino)allyl phosphonate products thus obtained in the synthesis of (enamino)-1,3-butadienes via Horner–Wadsworth–Emmons (HWE) reaction is also demonstrated.

Synthesis, characterization, X-ray structure and DNA photocleavage by cis-dichloro bis(diimine) Co(III) complexes - Ghosh, Smita; Barve, A. C.; Kumbhar, A. A.; Kumbhar, A. S.; Puranik, Vedavati G.; Datar, P. A.; Sonawane, U. B.; Joshi, Rohini R. (Journal of Inorganic Biochemistry, 2006)
Keywords: Acetic acid; acrylic acid; oxidative conversion of propane; rare earth-doped Mo-V-Sb catalysts

Synthesis of 4-aminomethyl-tetrahydrofuran-2-carboxylates with 2,4-cis and 2,4-trans relationships - Edwards, Alison A.; Sanjayan, Gangadhar J.; Hachisu, Shuji; Soengas, Raquel; Stewart, Alistair; Tranter, George E.; Fleet, George W. J. (Tetrahedron, 2006)
Templated tetrahydrofuran-based gamma-azido esters were prepared with the C-2 and C-4 functionalities in cis and trans relative configurations. This was achieved by ring contraction of the suitably protected 2-O-triflates of pentono-1,5-lactones (D-ribose and L-arabinose) with subsequent introduction of the azide via the 4-O-triflate. Access to a corresponding beta-azido ester was achieved in good yield. Little elimination product was observed by introduction of the azide via the 3-O-triflate. These azido esters are scaffolds. which may be predisposed to adopt secondary structural motifs, for example. for use as peptidomimetics; they may also be utilised for the preparation of stereodiverse compound libraries. (c) 2006 Elsevier Ltd All rights reserved.
Keywords: gamma amino acids; Peptidomimetics; scaffolds; sugar amino acids

Synthesis of annularly functionalised BINOL-based chiral cyclophanes - Srisailas, Muthialu; Rajakumar, Perurnal (Journal of Chemical Research-S, 2006)
Chiral cyclophanes with annular functionality were synthesised by coupling carbonyl dibromides with (S)-BINOL. Semi-empirical calculations by MOPAC (PM3) were also performed on the cyclophanes prepared to view their cavity sizes.
Keywords: annular functionality; chiral cyclophanes

Synthesis of azobenzenophanes with a large molecular cavity - Rajakumar, Perumal; Senthilkumar, B.; Srinivasan, Kannupal (Australian Journal of Chemistry, 2006)
The design and synthesis of four large-cavity azobenzenophanes, capable of forming photochemically controllable complexes with organic guest molecules, are described. These azobenzenophanes, possessing m-terphenyl, aromatic carbonyl, and chiral BINOL spacers, were synthesized from the corresponding bisphenols and dibromides using simple O-alkylation methodology. A preliminary photochemical study was carried out on the aromatic carbonyl spacer containing azobenzenophane, and the isosbestic points for the cis–trans isomerization process appeared at 319 and 419 nm.

Synthesis of beta-Ag2Se from organo-selenium precursor and silver nitrate in DMF via simultaneous reduction of selenium and silver salt - Khanna, P. K.; Singh, N.; Charan, Shobhit; Patil, K. R. (Materials Letters, 2006)
Reaction of selenium powder and silver nitrate in aqueous N,N'-dimethylformamide (aq. DMF) leads to formation of silver selenide. Similar reaction with cycloalkeno-1,2,3-selenadiazole an organic compound of selenium upon thermolysis, also produces silver selenide. It is believed that DMF activates selenium and reduces silver salt via in-situ generated hydrogen ion simultaneously. Slightly broadened X-ray diffraction pattern for pure beta silver selenide (beta-Ag2Se) was observed. Scanning electron microscopy (SEM) indicated that the agglomerated particles could be in the range of about 100 to 200 nm in dimension. EDAX analysis showed non-stoichiometric elemental ratio between silver and selenium. It is found that the weight percent of Ag is slightly higher than Se. However, free amorphous selenium is also detected by XPS analysis when the product is made by use of elemental selenium. Thermal analysis (TGA) revealed a small (4%) weight loss due to the presence of organics or the solvent from the reaction medium. (c) 2005 Elsevier B.V. All rights reserved.
Keywords: Chemical synthesis; nano powder; noble metal chalcogenides; Semiconductor

Synthesis of beta-amino alcohols from aromatic amines and alkylene carbonates using Na-Y zeolite catalyst - Shivarkar, Anandkumar B.; Gupte, Sunil P.; Chaudhari, Raghunath V. (Synlett, 2006)
A simple, efficient, and environmentally benign methodology for the synthesis of beta-amino alcohols from aromatic amines and alkylene carbonates in the presence of the highly active and reusable solid base catalyst Na-Y zeolite is demonstrated.
Keywords: Alkylation; alkylene carbonate; Amine; Amino alcohols; zeolite

Synthesis of cadmium selenide thin films at low-temperature by simple chemical route and their characterization - Hankare, P. P.; Delekar, S. D.; Asabe, M. R.; Chate, P. A.; Bhuse, V. M.; Khomane, A. S.; Garadkar, K. M.; Sarwade, B. D. (Journal of Physics and Chemistry of Solids, 2006)
Crystalline CdSe thin film has been deposited using appropriate precursor solution containing cadmium sulfate octahydrate, tartaric acid, potassium hydroxide, ammonia and sodium selenosulfate. The effect of parameters such as bath composition, deposition temperature, pH of the solution, speed of the rotation and the specificity of complexing agent on growth process is studied. The `as-deposited' CdSe thin film was found to be red in color, specularly reflective and well adherent to the glass substrate. The crystalline phase of the deposited sample was hexagonal wurtzite-type. The analysis of optical absorption data shows energy band gap energy (E-g) 2.01 eV. The morphological study and compositional analysis of film sample have been discussed. The electrical resistivity of CdSe thin film was found to the order of 10(6) Omega cm. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: XRD

Synthesis of corrosion inhibitive poly(2,5-dimethylaniline) coatings on low carbon steel - Shinde, V.; Sainkar, S. R.; Gangal, S. A.; Patil, P. P. (Journal of Materials Science, 2006)
An attempt has been made towards the synthesis of strongly adherent poly(2,5-dimethylaniline) coatings on low carbon steel substrates, with an objective of examining the possibility of using this polymer for corrosion protection of steel in chloride environment. In this work, the poly(2,5-dimethylaniline) coatings were synthesized by electrochemical polymerization of 2,5-dimethylaniline using sodium salicylate as a supporting electrolyte. The characterization of these coatings was carried out by cyclic voltammetry, UV-visible absorption spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. The results of these characterizations indicate that the aqueous salicylate solution is a suitable medium for the electrochemical polymerization of 2,5-dimethylaniline to generate strongly adherent and smooth poly(2,5-dimethylaniline) coatings on low carbon steel substrates. The performance of poly(2,5-dimethylaniline) as protective coating against corrosion of low carbon steel in aqueous 3% NaCl was assessed by the open circuit potential and the potentiodynamic polarization measurements. The potentiodynamic polarization measurement reveals that the poly(2,5-dimethylaniline) coating increases the corrosion potential and reduces the corrosion rate of low carbon steel almost by a factor of 50. This study clearly ascertains that the poly(2,5-dimethylaniline) has outstanding capability to protect low carbon steel against corrosion in chloride environment. (c) 2006 Springer Science + Business Media, Inc.

Thermotropic behavior of lithocholic acid derivative linked hydroxyethyl cellulose - Shaikh, V. A. E.; Maldar, Noormahamad N.; Lonikar, Shrikant Vitthal; Rajan, C. R.; Ponrathnam, S. (Journal of Applied Polymer Science, 2006)
Various mesogenic lithocholic acid (LA) derivatives [3-acetyl LA (LAAC); 3-propionyl LA (LAP), 3-cinnamoyl LA (LACin); 3-benzoyl LA (LAB), 3-(4-nitrobenzoyl) LA (LANB); and methyl-3-(3-carboxypropionyl) LA, i.e., LA methyl ester monosuccinate (LAMeMS)] were reacted with hydroxyethyl cellulose (HEC) to obtain a series of LA derivatives of HEC. These polymers were characterized by the mesogen content, 1.1, differential scanning calorimetry, and hot-stage coupled polarizing optical microscopy. The degree Of Substitution (DS) ranged from 0.27 to 1.11. Polymers HEC-LAB (DS = 1.11), HEC-LANB (DS = 0.80), HEC-LACin (DS = 0.76), and HEC-LAP (DS = 0.27) exhibited a mesophase on heating whereas HEC-LAB also showed a mesophase on cooling. The other polymers HEC-LAAC (DS = 0.89) and HEC-LAMeMS (DS = 0.36) did not reveal mesophase formation with either heating or cooling. It is observed that the formation of a mesophase is affected by the type of mesogen that is used rather than the mesogen content of the polymer. (c) 2006 Wiley Periodicals, Inc.
Keywords: hydroxyethyl cellulose; lithocholic acid; thermotropic

Transesterification of cyclic carbonates with methanol at ambient conditions over tungstate-based solid catalysts - Sankar, M.; Nair, C. Madhavan; Murty, K. V. G. K.; Manikandan, Palanichamy (Applied Catalysis A-General, 2006)
Dimethyl carbonate synthesis with 80 mol% yield is achieved through transesterification of ethylene carbonate with methanol at ambient conditions (RT and atmospheric pressure) using alkali and alkaline-earth tungstates as solid catalysts. The catalysts are efficient even at the sub-ambient temperatures. Reactions under CO2 pressure indicate that CO2 atmosphere retards the transesterification reaction completely below 100 degrees C. Experimental conditions of 150 degrees C and 3.4 MPa CO2 pressure are required to obtain maximum DMC yield of 71 mol%. Synthesis of DMC by one-pot synthesis using epoxide, CO2 and methanol is not as effective as that by two-step method with the present catalyst system. Raman and IR spectra of methanol-interacting tungstates indicate the formation of a methoxide ion species adsorbed at the catalyst surface as one possible reaction intermediates. (C) 2006 Elsevier B.V. All rights reserved.
Keywords: Dimethyl carbonate; ethylene carbonate; heterogeneous catalyst; Raman spectroscopy; sodium tungstate; transesterification

Unfavorable coordination of copper with methyl vinyl ketone in atom transfer radical polymerization - Mittal, A.; Sivaram, S.; Baskaran, D. (Macromolecules, 2006)

Unusual formation of nano-particles of CdO and Cd(OH)(2) from the reaction of dimethyl cadmium with DMF - Singh, Narendra; Charan, Shobhit; Patil, K. R.; Viswanath, A. K.; Khanna, P. K. (Materials Letters, 2006)
This paper presents generation of CdO and Cd(OH)(2) nano-particles from Dimethyl Cadmium in DMF. The CdO nano-particles were obtained instead of CdSe, even when the reaction was done in presence of 1,2,3-selenadiazole (the source of selenium) with Me2Cd in DMF (product-I). The direct reaction of Me2Cd in DMF also leads to formation of CdO (product-II). However, Cd(OH)(2) nano-particles were obtained when Me2Cd was refluxed in DMF for a few hours followed by reaction of H2S gas (product-III). The formation of Cd(OH)(2) was also established via decomposition Of Me2Cd:Et2O adduct (product-IV). Nano-particles of CdO and Cd(OH)(2) (product-I to product-IV) were characterized by X-ray powder diffraction (XRD), TEM and SEM/EDS measurements, FTIR, thermal analysis (TGA) and XPS analysis. The particle size of all the products as calculated by XRD patterns were in the range of about 20 nm. TEM images showed that the products are agglomerated clusters with the particles in the nano-meter regime. The synthesis however, is understood to be unusual as the reactions with selenium source and sulfur source should have generated the CdSe and CdS however, the end products were always found to be the product-I to product-IV (c) 2006 Elsevier B.V. All rights reserved.
Keywords: Chemical synthesis; Nanoparticles; Semiconductor; XRD

Unusual products in the reactions of phosphorus(III) compounds with N=N, C equivalent to C or conjugated double-bonded systems - Swamy, K. C. Kumara; Balaraman, Ekambaram; Pavan, M. Phani; Kumar, N. N. Bhuvan; Kumar, K. Praveen; Kumar, N. Satish (Journal of Chemical Sciences, 2006)
The diversity of products in the reaction of diethyl azodicarboxylate (DEAD)/diisopropyl azodicarboxylate (DIAD) and activated acetylenes with PIII compounds bearing oxygen or nitrogen substituents is discussed. New findings that are useful in understanding the nature of intermediates involved in the Mitsunobu reaction are highlighted. X-ray structures of two new compounds (2-t-Bu-4-MeC6H3O)P (μ-N-t-Bu)2P+[(NH-t-Bu)N[(CO2]-i-Pr)(HNCO2-i-Pr)]](Cl-)(2-t-Bu-4-MeC6H3OH)(23)and [CH2(6-t-Bu-4-Me-C6H2O)2P(O)C(CO2Me)C-(CO2Me)CClNC(O)Cl] (33) are also reported. The structure of23 is close to one of the intermediates proposed in the Mitsunobu reaction.

Vanadium-containing ethane-silica hybrid periodic mesoporous organosilicas: synthesis, structural characterization and catalytic applications - Shylesh, S.; Singh, A. P. (Microporous and Mesoporous Materials, 2006)
Vanadium-containing ethane-silica hybrid mesoporous silsesquioxane materials (V-HMM) with uniform hexagonal arrangement were prepared using C-18-, C-16- and C-14-alkyl trimethyl ammonium (ATMA) surfactants under basic conditions. The materials were characterized by PXRD, N-2 adsorption-desorption, UV-Visible spectroscopy, Raman, Si-29, C-13 and V-51 solid-state MAS NMR, TEM and SEM techniques. The characterization techniques revealed that the structural ordering, morphology as well as the percentage of metal incorporation depends strongly on the hydrophobic chain length of the surfactant. PXRD, electron microscopy and N-2 adsorptiondesorption analysis confirmed that the original hexagonal structure of the material is maintained after vanadium substitution. UV-Visible, V-51 NMR and Raman analysis certified that vanadium exists in a highly dispersed state and had tetrahedral coordination with the support surface. Liquid-phase epoxidation reaction of styrene using aqueous H2O2 and TBHP as oxidants, showed that the hybrid materials were highly active and more stable than conventional vanadosilicates. The high catalytic activity and improved epoxide selectivity of the V-HMM samples is related to the more hydrophobic environment inside the pore channels than the silica channels in V-MCM-41. (c) 2006 Elsevier Inc. All rights reserved.
Keywords: epoxidation; organo vanadosilicates; styrene; V-HMM; V-MCM-41

Well-defined poly(4-vinylbenzocyclobutene): synthesis by living anionic polymerization and characterization - Sakellariou, G.; Baskaran, D.; Hadjichristidis, Nikos; Mays, Jimmy W. (Macromolecules, 2006)
Living anionic polymerization of 4-vinylbenzocylobutene was performed in benzene at room temperature using sec-butyllithium as the initiator. Results of the kinetic studies indicated the termination- and transfer-free nature of the polymerization. Homopolymers with predictable molecular weights and narrow molecular weight distributions were produced, excluding the interference of the cyclobutene rings during initiation and propagation. Thermogravimetric analysis of poly( 4-vinylbenzocyclobutene) in air showed a small weight gain at similar to 200 degrees C, a rapid decomposition at similar to 455 degrees C, and a gradual decomposition at similar to 566 degrees C. This behavior was attributed to the formation of radicals from the pendent benzocyclobutene functionality through o-quinodimethane intermediates and simultaneous decomposition/ cross-linking reactions at high temperature. The living nature of the polymerization was also examined via sequential copolymerization with butadiene to form diblock copolymers.

4-Formylazetidin-2-one as a useful building block for the formal synthesis of xylo-(2S,3R,4R)-phytosphingosine and threo-(2S,3S)-sphingosine - Kale, Ajaykumar S.; Sakle, Prathmesh S.; Gumaste, Vikas K.; Deshmukh, Abdul Rakeeb A. S. (Synthesis-Stuttgart, 2007)
Stereoselective formal synthesis of xylo-(2S,3R,4R)-phytosphingosine and threo-(2S,3S)-sphingosine is described starting from an enantiopure formyl-substituted P-lactam. Grignard reaction of the N-Boc-protected-beta-lactam carbonyl group, followed by further transformations, provides a common intermediate for xylo-(2S,3R,4R)-phytosphingosine and threo-(2S,3S)-sphingosine.
Keywords: azetidin-2-one; beta-lactam; Grignard reaction; Phytosphingosine; Sphingosine

Activation and reactivity of epoxides on solid acid catalysts - Saikia, Lakshi; Satyarthi, J. K.; Srinivas, Darbha; Ratnasamy, P. (Journal of Catalysis, 2007)
The aminolysis of epoxides over novel solid catalysts (Bronsted-acidic SBA-15 functionalized with propylsulfonic acid and Lewis-acidic Ti-MCM-41) is reported. The acidic properties of these catalysts were determined by FTIR spectroscopy and temperature-programmed desorption of pyridine and NH3, respectively. The mesoporous solid acids of the present study are reusable and exhibit significantly higher catalytic activities than known catalysts for opening of the oxirane ring with nitrogen (aromatic and aliphatic amines)-containing and oxygen (alcohols)-containing nucleophiles. A range of beta-amino, alcohols with high regioselectivity and stereoselectivity were synthesized. Adsorption studies as well as the sigmoid shape of the conversion- versus-time plots show that the epoxide and amine compete for adsorption on the acidic sites (-SO3H or Ti4+) on the catalyst surface. Epoxide adsorption and activation on acid sites are the more critical processes. Catalytic activity decreases with increasing basicity of the amines and/or the alcohol, as well as the dielectric constant of the solvent. (C) 2007 Elsevier Inc. All rights reserved.
Keywords: aminolysis and alcoholysis of epoxides; beta-Amino alcohols; ring opening of epoxides; SBA-15 functionalized with propylsulfortic acid; Solid acids; Ti-MCM-41

Acylation of anisole with long-chain carboxylic acids over wide pore zeolites - Wagholikar, S. G.; Niphadkar, P. S.; Mayadevi, S.; Sivasanker, S. (Applied Catalysis A-General, 2007)
The acylation of anisole with long-chain carboxylic acids (hexanoic, octanoic and decanoic) has been studied over three large pore zeolites-beta (BEA), faujasite (FAU) and mordenite (MOR). The acylation of anisole with the long chain acids produced mainly the ketone (4-methoxy phenyl alkyl ketone) and small amounts of the ester (phenyl alkanoate). The results revealed the reaction to be influenced by the type of zeolite and its Si/Al ratio (acidity) besides the chain length (carbon number) of the carboxylic acid. In the acylation of anisole with hexanoic acid, the activity of the zeolites increased with dealumination as it led to the generation of mesopores that resulted in a decrease in diffusion resistance of the zeolites. The reactivity of the acids in the acylation reaction was found to decrease with increase in the carbon number. The experimental data have been fitted into a pseudo first order kinetic model. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: Acylation; Anisole; decanoic acid; hexanoic acid; octanoic acid; zeolites

Adsorption of zinc from aqueous solution using chemically treated newspaper pulp - Chakravarty, S.; Bhattacharjee, S.; Gupta, K. K.; Singh, M.; Chaturvedi, Hema T.; Maity, S. (Bioresource Technology, 2007)
Adsorption of zinc was studied using chemically modified newspaper pull) as an adsorbent in the aqueous medium. Quantitative chemical analysis showed the presence of trace quantities of some inorganic elements along with phosphorous in TNP. The experimental adsorption data fitted reasonably well to both Freundlich and Langmuir isotherm. pHzpc of TNP was 5.1, which indicated that the adsorbent was more potential for cationic adsorption. The adsorption kinetic data followed a pseudo-second order model for zinc. Optimum Zn2+ loading was 9.20 mg/g for 10.31 mg/l initial zinc concentration at pH 5.80. Zn2+ loading on TNP was dependent on initial zinc concentration. TNP was a potential adsorbent for the removal of Zn from the effluent of electroplating industry. (c) 2007 Elsevier Ltd. All rights reserved.
Keywords: Adsorption; newspaper pulp; TNP; zinc

All-solid-state' electrochemistry of a protein-confined polymer electrolyte film - Parthasarathy, Meera; Pillai, Vijayamohanan K.; Mulla, Imtiaz S.; Shabab, Mohammed; Khan, Mohammad Islam (Biochemical and Biophysical Research Communications, 2007)
Interfacial redox behavior of a heme protein (hemoglobin) confined in a solid polymer electrolyte membrane, Nafion (a perfluoro sulfonic acid ionomer) is investigated using a unique `all-solid-state' electrochemical methodology. The supple phase-separated structure of the polymer electrolyte membrane, with hydrophilic pools containing solvated protons and water molecules, is found to preserve the incorporated protein in its active form even in the solid-state, using UV-visible, Fluorescence (of Tryptophan and Tyrosine residues) and DRIFT (diffuse reflectance infrared Fourier transform) spectroscopy. More specifically, solid-state cyclic voltammetry and electrochemical impedance of the protein-incorporated polymer films reveal that the Fe2+-form of the entrapped protein is found to bind molecular oxygen more strongly than the native protein. In the `all-solid-state' methodology, as there is no need to dip the protein-modified electrode in a liquid electrolyte (like the conventional electrochemical methods), it offers an easier means to study a number of proteins in a variety of polymer matrices (even biomimetic assemblies). In addition, the results of the present investigation could find interesting application in a variety of research disciplines, in addition to its fundamental scientific interest, including protein biotechnology, pharmaceutical and biomimetic chemistry. (C) 2007 Elsevier Inc. All rights reserved.
Keywords: all-solid-state; cyclic voltammetry; hemoglobin; Impedance; Nafion; redox behavior

Analysis of mitochondrial DNA sequences in childhood encephalomyopathies reveals new disease-associated variants - Wani, Aijaz A.; Ahanger, Sajad H.; Bapat, Sharmila A.; Rangrez, Ashraf Y.; Hingankar, Nitin; Suresh, C. G.; Barnabas, Shama; Patole, Milind S.; Shouche, Yogesh S. (Plos One, 2007)
Background. Mitochondrial encephalomyopathies are a heterogeneous group of clinical disorders generally caused due to mutations in either mitochondrial DNA (mtDNA) or nuclear genes encoding oxidative phosphorylation (OXPHOS). We analyzed the mtDNA sequences from a group of 23 pediatric patients with clinical and morphological features of mitochondrial encephalopathies and tried to establish a relationship of identified variants with the disease. Methodology/Principle Findings. Complete mitochondrial genomes were amplified by PCR and sequenced by automated DNA sequencing. Sequencing data was analyzed by SeqScape software and also confirmed by BLASTn program. Nucleotide sequences were compared with the revised Cambridge reference sequence (CRS) and sequences present in mitochondrial databases. The data obtained shows that a number of known and novel mtDNA variants were associated with the disease. Most of the non-synonymous variants were heteroplasmic (A4136G, A9194G and T11916A) suggesting their possibility of being pathogenic in nature. Some of the missense variants although homoplasmic were showing changes in highly conserved amino acids (T3394C, T3866C, and G9804A) and were previously identified with diseased conditions. Similarly, two other variants found in tRNA genes (G5783A and C8309T) could alter the secondary structure of Cys-tRNA and Lys-tRNA. Most of the variants occurred in single cases; however, a few occurred in more than one case (e. g. G5783A and A10149T). Conclusions and Significance. The mtDNA variants identified in this study could be the possible cause of mitochondrial encephalomyopathies with childhood onset in the patient group. Our study further strengthens the pathogenic score of known variants previously reported as provisionally pathogenic in mitochondrial diseases. The novel variants found in the present study can be potential candidates for further investigations to establish the relationship between their incidence and role in expressing the disease phenotype. This study will be useful in genetic diagnosis and counseling of mitochondrial diseases in India as well as worldwide.

Anticorrosive properties of electrosynthesized poly(o-anisidine) coatings on copper from aqueous salicylate medium - Chaudhari, Sudeshna; Sainkar, S. R.; Patil, P. P. (Journal of Physics D-Applied Physics, 2007)
Poly( o-anisidine) ( POA) coatings were electrosynthesized on copper ( Cu) from an aqueous solution containing o-anisidine and sodium salicylate by using cyclic voltammetry, galvanostatic and potentiostatic modes. The extent of corrosion protection offered by these coatings to Cu in aqueous 3% NaCl solution was evaluated by the open circuit potential measurements, potentiodynamic polarization technique and electrochemical impedance spectroscopy. Potentiodynamic polarization and electrochemical impedance spectroscopy studies reveal that the POA acts as a protective layer on Cu against corrosion in 3% NaCl solution. The positive shift in the corrosion potential for the POA-coated Cu indicates the protection of the Cu surface by the POA. The POA coating synthesized by using cyclic voltammtery, galvanostatic and potentiostatic modes reduces the corrosion rate of Cu almost by a factor of 100, 100 and 7, respectively. The cyclic voltammetry was proved to be the better mode to adopt for the synthesis of more compact and strongly adherent POA coatings on Cu. The coatings synthesized by this mode were characterized by cyclic voltammetry, UV-visible absorption spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. It was found that the electrochemical polymerization of o-anisidine on Cu takes place after the passivation of its surface via the formation of Cu2O and/or copper salicylate complex and results in the generation of shiny, uniform and strongly adherent POA coatings. The optical absorption spectroscopy reveals the formation of the emeraldine salt form of POA. The results of this study clearly ascertain that the POA has outstanding potential to protect Cu against corrosion in a chloride environment.

Asymmetric synthesis of (R)-(-)-baclofen via asymmetric dihydroxylation - Thakur, V. V.; Paraskar, A. S.; Sudalai, A. (Indian Journal of Chemistry Section B-Organic Chemistry including Medicinal Chemistry, 2007)
A short and efficient asymmetric synthesis of (R)-(-)-baclofen, a selective GABA(B) agonist has been described with an overall yield of 14% and 85% ee. The Os-catalyzed Sharpless asymmetric dihydroxylation of alpha,beta-unsaturated olefin constitutes the key step in introducing stereogenic centers into the molecule.
Keywords: asymmetric dihydroxylation; baclofen; cyclic sulfate; gamma-aminobutyric acid; Parkinsons' disease

Attempt at taxonomical characterization of some Rhizobial species by intact cell MALDI mass spectrometry - Prabhu, R. R.; Kulkarni, Mahesh J.; Parasharami, V. A.; Santhakumari, B.; Paranjape, S. (World Journal of Microbiology & Biotechnology, 2007)
In the present study an attempt was made to exploit the benefit of intact cell MALDI mass spectrometry (ICM-MS) in bringing out similarities and differences among some Rhizobium species and a species of Agrobacterium based on specific mass:charge (m/z) values. Rhizobium species isolated from the root nodules of selected leguminous plants were analysed by ICM-MS. The spectra were acquired in the range of 500-10,000 Da yielding several peaks specific to each species. The peaks obtained corresponded to the respective bacterial cell surface molecules which were desorbed during matrix-assisted laser desorption ionization. The number of peaks were more in the range of 500-1200 Da. Dice similarity coefficient analysis of m/z values indicated that Rhizobium species isolated from Trigonella foenum-graecum and Pisum arvense showed more similarity than any other species. Agrobacterium species did show a few common m/z values in comparison with other Rhizobium species. This clearly shows that Agrobacterium is closely related to Rhizobium. Eventually, ICM-MS technique offers clear, distinct, and consistent results for replicates, in less than an hour's time, therefore this technique has high potential in molecular taxonomy.
Keywords: ICM-MS; legume; molecular taxonomy; Rhizobium; symbiotic

Au nanoparticle templated synthesis of pNIPAm nanogels - Singh, Neetu; Lyon, L. Andrew (Chemistry of Materials, 2007)

Bacterial enzyme mediated biosynthesis of gold nanoparticles - Bharde, Atul A.; Kulkarni, Aarohi; Rao, Mala; Prabhune, Asmita; Sastry, Murali (Journal of Nanoscience and Nanotechnology, 2007)
Development of synthesis methods for anisotropic metal nanoparticles is of considerable interest due to their remarkable optoelectronic properties. Various shapes ranging from rods to cubes to tetrapods and prisms may be obtained by chemical methods. Here we show that anisotropic gold nanoparticles can be synthesized biologically by the bacterium Actinobacter spp. when challenged with gold chloride in the presence of Bovine serum albumin (BSA). We also observed that synthesis of gold nanoparticles occur with simultaneous induction of the protease enzyme secreted by the bacterium in the presence of BSA. The presence of BSA helps to enhance the rate of gold nanoparticles biosynthesis and may also impart some shape control. Controlling simple experimental conditions like incubation temperature and presence or absence of oxygen have drastic effect on the reaction rate and the morphology of the particles. Various assay experiments show that the presence of enzyme protease can act as a reducing as well as shape directing agent.
Keywords: Biosynthesis; bovine serum; gold nanoparticles

Benzylsulfonic acid functionalized mesoporous Zr-TMS catalysts: an efficient and recyclable catalyst for the preparation of coumarin derivatives by pechmann condensation reaction - Selvakumar, S.; Chidambaram, M.; Singh, A. P. (Catalysis Communications, 2007)
Benzylsulfonic acid functionalized mesoporous Zr-TMS (Zr-TMS-BSA, Zr-TMS, zirconia based transition metal oxide mesoporous molecular sieves) catalyst is used as an alternative to conventional acid catalysts in the von Pechmann condensation of aromatic alcohols with ethyl acetoacetate leading to the formation of coumarin derivatives in solvent free condition at 150 degrees C. Three types of coumarins, 7-hydroxy-4-methylcoumarin (beta-methylumbelliferone), 7-methoxy-4-methylcoumarin (Methyl-4-methylumbelliferyl ether) and 7,8-benzo-4-methylcoumarin derivatives have been prepared using resorcinol, 3-methoxyphenol and 1-naphthol, respectively. The catalytic activity and the recycle studies of the catalyst in all the three reactions proved the superior performance of the catalyst. Further the products were confirmed by GC, elemental analysis, melting point and NMR techniques. Finally, the probable mechanism for Pechmarm condensation using Zr-TMS-BSA catalyst has been reported. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: benzylsulfonic acid; Pechmann condensation and coumarins; Zr-TMS-BSA catalysts

Bile salt hydrolase, the member of Ntn-hydrolase family: differential modes of structural and functional transitions during denaturation - Kumar, R. Suresh; Suresh, C. G.; Brannigan, James A.; Dodson, Guy G.; Gaikwad, Sushama M. (IUBMB Life, 2007)
Conformational transitions and functional stability of the bile salt hydrolase (BSH; cholylglycine EC: 3.5.1.24) from Bifidobacterium longum (BlBSH) cloned and expressed in E. coli were studied under thermal, chemical and pH-mediated denaturation conditions using fluorescence and CD spectroscopy. Thermal and Gdn-HCl-mediated denaturation of BlBSH is a multistep process of inactivation and unfolding. The inactivation and unfolding of the enzyme was found to be irreversible. Enzyme activity seems sensitive to even minor conformational changes at the active site. Thermal denaturation as such did not result in any insoluble protein aggregates. However, on treating with 0.25-1 M Gdn-HCl the enzyme showed increasing aggregation at temperatures of 40-55 degrees C indicating more complex structural changes taking place in the presence of chemical denaturants. The enzyme secondary structure was still intact at acidic pH (pH 1-3). The perturbation in the tertiary structure at the acidic pH was detected through freshly formed solvent exposed hydrophobic patches on the enzyme. These changes could be due to the formation of an acid-induced molten globule-like state.
Keywords: Aggregation; Bile salt hydrolase; molten-globule; Unfolding

Bioconjugation of soft nanomaterials - Singh, Neetu; Blackburn, William H.; Lyon, L. Andrew (Biomedical Nanostructures, 2007)

Bio-milling technique for the size reduction of chemically synthesized BiMnO3 nanoplates - Mazumder, Baishakhi; Uddin, Imran; Khan, Shadab; Ravi, Venkat; Selvraj, Kaliaperumal; Poddar, Pankaj; Ahmad, Absar (Journal of Materials Chemistry, 2007)
Wet- chemical techniques for the synthesis of complex oxide materials have advanced significantly; however, achieving finely dispersed nanoparticles with sizes less than 10 nm still remains challenging, especially for the perovskite family of compounds. On the other hand, a fungusmediated synthesis technique has recently shown potential to synthesize perovskites such as BaTiO3 with sizes as small as 5 nm. Here we report, for the first time, the use of fungal biomass, at room temperature, to break down chemically synthesized BiMnO3 nanoplates ( size similar to 150 - 200 nm) into very small particles (, 10 nm) while maintaining their crystalline structure and the phase purity. This novel technique that we have named as `` bio- milling'' holds immense potential for synergically utilizing both chemical and biological synthesis techniques to synthesize complex oxide nanoparticles with particle sizes less than 10 nm with the proper crystalline phase.

Blocking effects in irreversible adsorption of linear macromolecules - Shelke, Pradip B.; Banpurkar, Arun G.; Ogale, S. B.; Limaye, A. V. (Surface Science, 2007)
{A new variant of random sequential adsorption (RSA), namely random sequential ballistic adsorption (RSBA), is proposed to explore the possible role of blocking effects in the adsorption dynamics of ballistically arriving objects. These objects upon adsorption can protrude outside the substrate and in turn can obstruct and hence reject the adsorption of newly arriving objects. Adsorption of linear macromolecules (modeled as infinitesimally thin needles), on a two-dimensional continuum substrate is studied using RSBA model. It is shown analytically that in late time regime, the number n(t) of adsorbed objects at time t follows a power law n(t) similar to t(alpha), as in RSA, but with a different exponent
Keywords: Adsorption; adsorption kinetics; Monte Carlo simulations; random sequential adsorption (RSA)

Bowman-birk protease inhibitor from the seeds of vigna unguiculata forms a highly stable dimeric structure - Rao, K. N.; Suresh, C. G. (Biochimica et Biophysica Acta-Proteins and Proteomics, 2007)
Different protease inhibitors including Bowman-Birk type (BBI) have been reported from the seeds of rigna unguiculata. Protease isoinhibitors of double-headed Bowman-Birk type from the seeds of Vigna unguiculata have been purified and characterized. The BBI from Vigna unguiculata (Vu-BBI) has been found to undergo self-association to form very stable dimers and more complex oligomers, by size-exclusion chromatography and SDS-PAGE in the presence of urea. Many BBIs have been reported to undergo self-association to form homodimers or more complex oligomers in solution. Only one dimeric crystal structure of a BBI (pea-BBI) is reported to date. We report the three-dimensional structure of a Vu-BBI determined at 2.5 A resolution. Although, the inhibitor has a monomer fold similar to that found in other known structures of Bowman-Birk protease inhibitors, its quaternary structure is different from that commonly observed in this family. The structural elements responsible for the stability of monomer molecule and dimeric association are discussed. The Vu-BBI may use dimeric or higher quaternary association to maintain the physiological state and to execute its biological function. (C) 2007 Elsevier B.V. All rights reserved.
Keywords: Bowman-Birk protease inhibitor; plant protease inhibitor; protein-protein interaction; Vigna unguiculata

Catalytic performances of silicotungstic acid/zirconia supported SBA-15 in an esterification of benzyl alcohol with acetic acid - Sawant, Dhanashri P.; Vinu, A.; Justus, Josena; Srinivasu, P.; Halligudi, Shivaraj B. (Journal of Molecular Catalysis A-Chemical, 2007)
Liquid phase esterification of benzyl alcohol (BA) to benzyl acetate (Peach fragrance) with an acetic acid (AA) has been investigated with 12-silicotungstic acid supported on zirconia embedded inside SBA-15 (STA/ZrO2/SBA- 15) as the catalyst. Catalysts were unambiguously characterized by XRD, N-2 adsorption-desorption, FF-IR pyridine adsorption techniques and the total amount of acidity of different STA loaded catalysts was estimated by TPD of NH3. The optimization of reaction conditions of an esterification of BA with AA was performed with 15 wt.% STA/22.4 wt.% ZrO2/SBA-15 calcined at 1123 K by varying catalyst concentration (1-10 wt.% of reaction mixture); temperature, 353-383 K and AA:BA molar ratio as 0.5-3. The 15 wt.% STA/22.4 wt.% ZrO2/SBA-15 calcined at 1123 K was found to have the highest acidity and more active in the reaction. Under the optimized reaction conditions, the 15 wt.% STA/22.4 wt.%ZrO2/SBA-15 calcined at 1123 K gave 59% BA conversion with selectivity for benzyl acetate as high as 96% within 2 h of reaction time. (c) 2007 Elsevier B.V. All rights reserved.
Keywords: 12-silicotungstic acid; Benzyl acetate; Benzyl alcohol; Esterification; SBA-15

Central core of uprolides D and E: a survey of some ring closing metathesis approaches - Ramana, C. V.; Salian, Sumanth R.; Gurjar, Mukund K. (Tetrahedron Letter, 2007)
A preliminary study dealing with the feasibility of ring closing metathesis and ene-yne ring closing metathesis to construct the central bicyclic cores of uprolides D and E was investigated. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: cembranolides; ene-yne metathesis; Ring closing metathesis; Sharpless asymmetric epoxidation; uprolides D and E

Characterization and catalytic activity of cobalt containing MCM-41 prepared by direct hydrothermal, grafting and immobilization methods - Bhoware, Shrikant S.; Singh, A. P. (Journal of Molecular Catalysis A-Chemical, 2007)
{Cobalt containing hexagonal mesoporous molecular sieves (MCM-41) were prepared by different methods viz., direct hydrothermal synthesis, grafting and immobilization. The calcined material was characterized by various spectroscopic tools such as powder X-ray diffraction (XRD), N-2 adsorption-desorption isotherms, Fourier transformed infra-red (Fr-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance UV-vis and X-ray photoelectron spectroscopy (XPS). The XRD patterns show the highly intense (100) reflection peak in the range 2-3 degrees (2 theta angle), characteristic of mesoporous material. Higher order reflection peaks suggest highly ordered mesoporous structure. N2 adsorption-desorption isotherms are of type IV according to IUPAC classification and the steep rise in the isotherms in the narrow range 3.5-4.5 of relative pressure (P/P-0) is due to the condensation of N-2 gas molecules in the pores (characteristic of mesoporous structure). In FT-IR increase in the intensity of band at 960 cm(-1) with the increase of the cobalt content in Co-MCM-41 samples indicate the incorporation of cobalt ions in the framework of MCM-41. SEM and TEM reveal spherical morphology for the cobalt substituted MCM-41. UV-vis spectra demonstrate the characteristic features of framework and extraframework cobalt in MCM-41. Cobalt is in +2 oxidation state as evidenced from UV-vis and XPS. The catalysts were tested for the side chain oxidation of ethylbenzene using 70 wt.% tert-butyl hydrogen peroxide as an oxidant with and without the use of solvent. Solvents have effect in the catalytic activity and selectivity. In the absence of solvent, substituted cobalt [
Keywords: 2-butanol; cyclohexanone; Mesoporous molecular sieves; MPV reduction

Chemoselective alkane oxidations by reactive superoxovanadium(V) species in vanadosilicate molecular sieves - Srinivas, D.; Ratnasamy, P. (From ZEOLITES to Porous Mof Materials: The 40th Anniversary of International ZEOLITE Conference, Proceedings of The 15th International ZEOLITE Conference, 2007)
Unlike their titanium analogs, vanadosilicate molecular sieves catalyze the oxidation of the terminal (primary) C-H bonds in paraffins. This dissimilarity is attributed to differences in the type of reactive superoxo species generated on contact with oxidant. The latter were identified and characterized by in situ EPR and DRUV-vis spectroscopic techniques. By a suitable choice of silicate structure (VS-1 or V-MCM-41), solvent and oxidant (H(2)O(2), tert.-butyl hydroperoxide or H(2)+O2()), the V-O bond covalency and mode of O-O bond cleavage in the oxo-species and thereby, the chemoselectivity in the oxidation of the terminal carbon atoms in paraffins could be controlled.

Cholesterol-linked beta-cyclodextrin - a thermotropic liquid-crystalline derivative - Shaikh, Vasi Ahmed Ebrahim; Lonikar, Shrikant Vitthal; Dhoble, Deepa Arun; Pawar, G. M. (Bulletin of the Chemical Society of Japan, 2007)
Liquid-crystalline derivative of ss-cyclodextrin (BCD) was prepared by covalent linking of monocholesteryl succinate (ChMS) with ss-cyclodextrin. To the best of our knowledge, this was first ever attempt so far of its kind, in which BCD has been converted into its liquid-crystalline derivative through covalent linkage of a mesogen. The degree of substitution (DS) obtained was approximate to 2.00. The product was characterized by various techniques, such as FT-IR, NMR, DSC, hot-stage-coupled optical polarizing microscopy (OPM), microanalysis and chemical methods. Cholesterol-linked ss-cyclodextrin (CDCh) derivative was found to exhibit thermotropic liquid-crystalline behavior. The product exhibited birefringence during first heating above 130 degrees C, and it became isotropic at about 180 degrees C, whereas the parent compound BCD decomposed without melting above 250 degrees C. A comparison of CDCh derivative to similar liquid-crystalline polysaccharide derivatives is presented.

Chromium-containing small pore mesoporous silicas: synthesis, characterization and catalytic behavior in the liquid phase oxidation of cyclohexane - Shylesh, S.; Samuel, Prinson P.; Singh, A. P. (Applied Catalysis A-General, 2007)
Organic-inorganic hybrid mesoporous silica materials containing chromium and various organo trialkoxysilanes (chloropropyl, vinyl, methyl) were prepared by the co-condensation method, in the presence of cetyl trimethyl ammonium surfactants. The hybrid material, containing chromium, retains one X-ray diffractogram (XRD) peak up to a molar ratio of 1: 1 between tetra ethyl orthosilicate (TEOS) and organosilane in the synthesis gel. Small pore mesoporous chromium-silica samples can be prepared from the large pore hybrid mesoporous chromium samples by calcination. By this method, the pore size of the material can be tailored into the supermicroporous region, without changing the chain length of the surfactant used in the assembly process, as judged from the XRD and N-2 sorption isotherms. The shrinkage in pore size is dependent on the nature and percentage of the organic pendant groups, such that the chloro propyl and vinyl pendant mesoporous material show more pore size shrinkage than the smaller methyl pendant units. Because of the tailorable pore size and with better textural characteristics, the chromium samples show better catalytic activity in the aerial oxidation reaction of cyclohexane than the conventional chromium-containing mesoporous material, like Cr-MCM-41, under a solvent free system. Among the porous chromium catalysts, the samples prepared using chloro propyl silane show higher cyclohexane conversion and cyclohexanone selectivity and behave as a true heterogeneous catalyst. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: chromium; Cyclohexane; Oxidation; small pore silicas

Comparative catalytic activity of Mn(Salen) complexes grafted on SBA-15 functionalized with amine, thiol and sulfonic acid groups for selective aerial oxidation of limonene - Salkia, Lakshi; Srinivas, Darbha; Ratnasamy, Paul (Microporous and Mesoporous Materials, 2007)
SBA-15 molecular sieves were functionalized with propylamine, propylthiol and propylsulfonic acid groups. Mn(Salen)Cl complexes were grafted on these organo-functionalized SBA-15. The support and the type of organo-functional group influenced the electronic structure (oxidation state and redox behavior) and chemo selectivity of the Mn-complexes in the oxidation of limonene. The Mn ions were reduced from +3 to +2, the extent of this reduction on different supports decreasing in the order: SBA- 15-pr-SH > SBA- 15-prSO(3)H > SBA-15-pr-NH2- Mn(Salen)Cl supported on propylthiol-functionalized SBA-15 yielded the 1,2-limonene epoxide with 100% chemo- and regioselectivity. Higher electron density at the site of Mn ions and the consequent lower redox potential of the Mn-complexes on immobilization are the probable causes for their efficient and selective catalytic activity. Solvents, additives (N-MeIm) and co-reagents (iso-butyraldehyde), which facilitated formation of Mn2+ ions, enhance the catalytic activity. A part of the Mn complexes was leached out of the solid phase during the reaction and the extent of this with different catalysts decreased in the order: SBA-l5-pr-NH2-Mn(Salen)Cl > SBA- 15-pr-SO3H-Mn(Salen)Cl > SBA- 15-pr-SH-Mn(Salen)Cl. (C) 2007 Elsevier Inc. All rights reserved

Confinement of nano CdS in designated glass: a novel functionality of quantum dot-glass nanosystems in solar hydrogen production - Kale, Bharat B.; Baeg, Jin-Ook; Apte, Sanjay K.; Sonawane, Ravindra S.; Naik, Sonali D.; Patil, Kashinath R. (Journal of Materials Chemistry, 2007)
The present work is the investigation of our novel approach to designing quantum dot-glass nanosystems by confining nano CdS in designated glass and the first employment of such a quantum dot system in solar hydrogen production. The CdS quantum dots were grown in a special glass matrix, which involved a sequence of steps. The obtained glass was of uniformly bright yellow in color and the bulk glass was pulverized to a fine powder of micron size particles. The glass powder was characterized structurally and morphologically. X-Ray diffraction and electron diffraction patterns reveal a hexagonal crystallite system for the CdS quantum dots. Field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray fluorescence spectroscopy and chemical leaching with HCl studies demonstrate that the 2.5 nm size CdS quantum dots distribute homogeneously in a monodispersed form in the glass domain and on the surface with a ``partially embedded exposure'' configuration. This disposition imparts an excellent photostability against photocorrosion and also a facile catalytic function. Therefore, even a very small amount of CdS quantum dots (0.005 g per gram of glass powder) is able to photodecompose H2S under visible light (lambda >= 420 nm) both in alkaline and pure aqueous media and produce solar hydrogen with markedly high quantum yields of 17.5 and 11.4%, respectively at 470 nm. Salient features like reusability after simple washing, corrosionless-stability and remarkable catalytic activity of this quantum dot-glass nanosystem are brought forth by our novel catalyst design and are much acclaimed in large scale solar H-2 production.

Constrained variational response to fock-space multi-reference coupled-cluster theory: formulation for excited-state electronic structure calculations and some pilot applications - Manohar, Prashant Uday; Pal, Sourav (Computational Methods in Science and Engineering Vol 1: Theory and Computation: Old Problems and New Challenges, 2007)
Fock-space (FS) multi-reference (MR) coupled-cluster (CC) method has emerged as compact tool to account for electronic structure of open-shell systems and molecules in low-lying excited states. Development of linear response (LR) has been one of the challenging problems in FSMRCC due to multiple-root nature of effective Hamiltonian. The recently developed constrained variational approach (CVA) has opened up a promising tool for efficient evaluation of analytic response properties. In this article, we present formulation of the method for excited state calculations. We discuss the decoupling of equations as a result of spin-adaptation and present some preliminary results for analytical dipole moments and polarizabilities of some molecules in low-lying triplet excited states.
Keywords: CVA; Dipole moment; excited states; FSMRCC; polarizability

Controlled covalent functionalization of multiwalled carbon nanotubes using [4+2] cycloaddition of benzocyclobutenes - Sakellariou, Georgios; Ji, Haining; Mays, Jimmy W.; Hadjichristidis, Nikos; Baskaran, Durairaj (Chemistry of Materials, 2007)

Convenient chromatography-free access to enantio-pure 6,6’-di-tert-butyl-1,1’- binaphthalene-2,2’-diol- its 3,3’-dibromo, di-tert-butyl and phosphorus derivatives: utility in asymmetric synthesis - Balaraman, Ekambaram; Swamy, K. C. Kumara (Tetrahedron-Asymmetry, 2007)
A simple chromatography-free high-yielding synthesis of the hexane-soluble enantiopure 6,6′-di-tert-butyl-1,1′-binaphthalene-2,2′-diol 3 (6,6′-di-tert-butyl BINOL) using Friedel–Crafts reaction on 1,1′-binaphthalene-2,2′-diol 1 (BINOL) is described. The enantiomeric purity was fully maintained in the reaction. Compound 3 has been used as an entry point for the convenient chromatography-free synthesis of 3,3′,6,6′-tetra-tert-butyl BINOL 4 and 3,3′-dibromo-6,6′-di-tert-butyl BINOL 5. A straightforward route to enantiopure bisphosphites [(6,6′-R2C20H10O2)P]2[O2C20H10-6,6′-R2] [R = H 15, t-Bu 16] by simply reacting phosphorochloridite (6,6′-R2C20H10O2)PCl [R = H 20, t-Bu 6] with metallic sodium is highlighted. The identity of 15 and 16 as their selenium-oxidized products 17 and 18 (at phosphorus center) is confirmed by X-ray crystallography (17 in the enantiopure form and 18 as racemate). Various enantiopure phosphoramidites of the modified BINOL have been synthesized. It is established that even when the phosphoramidites derived from the unsusbstituted BINOL 1 fail to give an appreciable optical induction in the asymmetric reduction of acetophenone/phenacyl chloride, those derived from 3 do induce moderate chiral induction (up to 30% ee in the case for acetophenone and 43% ee in the case of phenacyl chloride), thus leaving scope for further improvement in ee for related reactions.

Copolyesters based on poly(butylene terephthalate)s containing cyclohexyl and cyclopentyl ring: Effect of molecular structure on thermal and crystallization behavior - Sandhya, T. E.; Ramesh, C.; Sivaram, S. (Macromolecules, 2007)
In an effort to understand the role of molecular structure on the thermal properties of polyesters and copolyesters, the following polyesters were synthesized: poly(1,4-cyclohexane dimethylene terephthalate) (PCT), poly(butylene-1,4-cyclohexane dicarboxylate) (PBCD), poly (1,3-cyclopentane dimethylene terephthalate) (PCPDT), and poly(butylene-1,3-cyclopentane dicarboxylate) (PBCP). PCT and PCPDT are semicrystalline polymers with crystallization and melting temperatures higher than poly(butylene terephthalate) (PBT). However, PBCD and PBCP have lower glass transition temperature than PBT. From these homopolymers a series of poly(butylene-co-1,4-cyclohexane dimethylene terephthalate) (P(BT-co-CT )), poly(butylene terephthalate-co-1,4cyclohexane dicarboxylate) (P(BT-co-BCD)), poly(butylene-co-1,3-cyclopentylene dimethylene) (P(BT-co-CPDT)), and poly(butylene terephthalate-co-1,3-cyclopentane dicarboyxlate) (P(BT-co-PBCP)) random copolyesters were synthesized for the first time, and their cocrystallization behavior was investigated using differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD). The copolymers were found to be statistically random and crystallized in all compositions. The P(BT-co-CT) and (P(BT-co-CPDT) copolyesters exhibited typical eutectic behavior in melting and crystallization, which indicated isodimorphic cocrystallization behavior. On the other hand, in the case of P(BT-co-BCD) and P(BT-co-PBCP) copolymers, the melting and crystallization temperatures showed linear dependency with composition, indicating isomorphic-like crystallization behavior.

Copper phthalocyanine films deposited by liquid-liquid interface recrystallization technique (LLIRCT) - Patil, K. R.; Sathaye, S. D.; Hawaldar, Ranjit R.; Sathe, B. R.; Mandale, A. B.; Mitra, A. (Journal of Colloid and Interface Science, 2007)
The simple recrystallization process is innovatively used to obtain the nanoparticles of copper phthalocyanine by a simple method. Liquid-liquid interface recrystallization technique (LLIRCT) has been employed successfully to produce small sized copper phthalocyanine nanoparticles with diameter between 3-5 nm. The TEM-SAED studies revealed the formation of 3-5 nm sized with beta-phase dominated mixture of alpha and beta copper phthalocyanine nanoparticles. The XRD, SEM, and the UV-vis studies were further carried out to confirm the formation of copper phthalocyanine thin films. The cyclic voltametry (CV) studies conclude that redox reaction is totally reversible one electron transfer process. The process is attributed to Cu(II)/Cu(I) redox reaction. (C) 2007 Elsevier Inc. All rights reserved.
Keywords: Copper phthalocyanine; cyclic voltametry; nanoparticulate films

Copper(II) ion exchanged A1SBA-15: a versatile catalyst for intermolecular hydroamination of terminal alkynes with aromatic amines - Shanbhag, Ganapati V.; Joseph, Trissa; Halligudi, Shivaraj B. (Journal of Catalysis, 2007)
The hydroarnination reaction offers a very attractive route for the synthesis of alkylated amines and their derivatives with no byproduct formation. AISBA-15 was synthesized by isomorphous substitution of aluminum into the framework of SBA-15, which induces the Bronsted acid sites, and these were exchanged with metal ions such as Cu2+, Zn2+, and Pd2+. The catalysts were characterized by XRD, N-2-sOrption, SEM, TEM, acidity measurements by FT-IR pyridine adsorption, H-2-TPR, (27)AI MAS NMR, and Si-29 MAS NMR. Hydroamination of phenylacetylene (PhAc) with 2,4-xylidine has been used as a test reaction, which gave N-(1-phenylethylidene)-2,4-dimethylaniline with no byproduct formation. CuAlSBA-15 and CuAIMCM-41 showed around three times greater activity in hydroamination of PhAc compared with Cu-clay and Cu-beta, due to the moderate Lewis acidity of Cu2+ present in mesoporous supports. The performance of the CuAlSBA-15 was also determined with different alkynes and amines to evaluate the catalyst's general applicability in hydroamination reactions. (c) 2007 Elsevier Inc. All rights reserved.
Keywords: A1SBA-15; addition; alkyne; Amine; Copper catalyst; heterogeneous; hydroamination; ion exchange; Mesoporous

Co-precipitation technique to prepare BaTa2O6 - Navale, S. C.; Samuel, Violet; Gaikwad, A. B.; Ravi, V. (Ceramics International, 2007)
A mixture of ammonium oxalate and ammonium hydroxide was used to co-precipitate barium and tantalum ions as barium oxalate and tantalum hydroxide under basic conditions. On calcination at 750 degrees C, this precursor yielded BaTa2O6 (BT) ceramics. This is much lower temperature as compared to that prepared by traditional solid-state method (1000 degrees C) as reported for the formation of BaTa206. Transmission electron microscope (TEM) investigations revealed that the average particle size is 70 nm for the calcined powders. The room temperature dielectric constant at 1 kHz is found to be 100. (c) 2005 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
Keywords: barium tantalate; Ceramics; Electron microscopy; Oxides; X-ray diffraction

Coprecipitation technique to prepare CoTa2O6 and CoNb2O6 - Mulla, Imtiaz S.; Natarajan, N.; Gaikwad, A. B.; Samuel, V.; Guptha, U. N.; Ravi, V. (Materials Letter, 2007)
An aqueous solution of sodium hydroxide was used to coprecipitate cobalt and tantalum (or niobium) ions from their precursors as hydroxides under basic conditions. This precipitate yielded CoTa2O6 (CT) or CoNb2O6 (CN) ceramics on calcining at 700 degrees C, i.e. at a temperature much lower than 900 degrees C, reported for the formation of these powders prepared by the traditional solid state method. The X-ray diffraction (XRD) studies were employed to investigate phase contents and lattice parameters. The morphology of the synthesized powders was investigated by transmission electron microscopy (TEM). (c) 2006 Elsevier B.V. All rights reserved.
Keywords: Chemical synthesis; electronic materials; Oxides; X-ray methods

Coprecipitation technique to prepare NiNb2O6 - Samuel, V.; Gaikwad, A. B.; Jadhav, A. D.; Natarajan, N.; Ravi, V. (Materials Letter, 2007)
A mixture of ammonium carbonate and ammonium hydroxide was used to coprecipitate nickel and niobium ions as nickel carbonate and niobium hydroxide under basic conditions. This precursor yielded NiNb2O6 (NN) ceramics on calcining at 700 degrees C (at a temperature lower than 800 degrees C which is necessary for the formation of NiNb2O6 when prepared by the traditional solid state method). The average particle size and morphology of these powders were investigated by transmission electron microscope (TEM). (c) 2006 Elsevier B.V. All rights reserved.
Keywords: Chemical synthesis; Electron microscopy; electronic materials; Oxides; X-ray methods

Cross- and axial-peak intensities in 2D-SLF experiments based on cross-polarization - the role of the initial density matrix - Das, Bibhuti B.; Ajithkumar, Thalasseril G.; Sinha, Neeraj; Opella, Stanley J.; Ramanathan, K. V. (Journal of Magnetic Resonance, 2007)
Simulations and experiments on simple oriented systems have been used to estimate the relative ratio of cross-peak to axial-peak intensities in 2D-SLF experiments based on dipolar oscillations during cross-polarization (CP). The density matrix prior to dipolar evolution is considered and for an isolated spin pair, it is shown that direct calculations of the ratios match well with simulations and experimental results. Along with the standard CP pulse sequence, two other pulse sequences namely CP with polarization inversion (PI-CP) and another novel variation of the standard CP experiment (EXE-CP) reported recently have been considered. Inclusion of homonuclear dipolar coupling has been observed to increase the axial-peak intensities. In combination with Lee-Goldburg (LG) decoupling, experiments on an oriented liquid crystalline sample have been carried out and the performance of the pulse schemes have been compared. The applicability of the new pulse sequence for different samples and different nuclei is discussed. Such studies are expected to lead to a better understanding of the experiments and to the design of useful pulse sequences. (C) 2007 Elsevier Inc. All rights reserved.
Keywords: cross polarization; oriented molecules; PISEMA; SLF

Cross-linking assessment after accelerated ageing of ethylene propylene diene monomer rubber - Tomer, N. S.; Delor-Jestin, Florence; Singh, R. P.; Lacoste, Jacques (Polymer Degradation and Stability, 2007)
The ageing of filled and cross-linked ethylene propylene diene elastomer (EPDM) has been studied under accelerated UV irradiation (lambda >= 290 nm) at 60 degrees C, thermal ageing at 100 degrees C and in nitric acid vapours for different time intervals. Hardness measurements were performed. DSC-thermoporosimetry was used to estimate the mesh size distribution and cross-linking densities for each ageing. The development of functional groups was monitored by ATR spectroscopy. An increase in oxidation with exposure time after the different types of ageing was observed. The thermal stability of EPDM was assessed by TGA and evolved volatile gases were identified using FTIR spectroscopy. (c) 2006 Elsevier Ltd. All rights reserved.
Keywords: ageing; EPDM; Oxidation; thermal analysis; thermoporosimetry

Cu(OTf)(2) catalyzed high yield synthesis of hantzsch 1,4-dihydropyridines - Paraskar, Abhimanyu S.; Sudalai, Arumugam (Indian Journal of Chemistry Section B-Organic Chemistry including Medicinal Chemistry, 2007)
Copper(II) triflate catalyzes efficiently the three-component condensation of aldehydes, beta-ketoesters and ammonium acetate in acetonitrile at 25 degrees C to afford the corresponding Hantzsch 1,4-dihydropyridines in high yields.
Keywords: 4-dihydropyridines; anti-hypertensive drug; calcium channel blockers; cardiovascular diseases; Hantzsch 1; three-component condensation

Decomposition and/or hydrogenation of hydrogen peroxide over Pd/Al2O3 catalyst in aqueous medium: factors affecting the rate of H2O2 destruction in presence of hydrogen - Choudhary, Vasant R.; Samanta, Chanchal; Jana, Prabhas (Applied Catalysis A-General, 2007)
Hydrogen peroxide destruction by its decomposition and/or hydrogenation to water in the presence of H-2 over Pd(5 wt.%)/Al2O3 catalyst in an aqueous reaction medium, similar to that used in the H-2-to-H2O2 oxidation, has been thoroughly investigated at different reaction conditions. The H2O2 destruction is strongly influenced by the oxidation state of Pd in the catalyst and also by the presence of different halide anions (viz. F-, Cl-, Br- and I-) in the acidic aqueous medium or in the catalyst, depending upon the concentration of halide anions. The cations associated with halide anions have, however, a little or no influence on the H2O2 destruction. The iodide anions strongly poisoned the catalyst, even at their very low concentration. The fluoride anions have only a small effect on the H2O2 destruction. The chloride or bromide anions drastically inhibit the rapid H2O2 decomposition, but promote the slower H2O2 hydrogenation. The H2O2 destruction reactions are strongly influenced by the halide anion and acid concentrations. The presence of acid (protons) plays a very important role in drastically reducing the H2O2 destruction, particularly in the presence of chloride anions. Both in the presence and absence of Cl- or Br- anions, the H2O2 destruction activity of the catalyst is markedly reduced because of the oxidation of Pd but it is drastically increased due to the presence of H-2. A plausible reaction mechanism for the rapid H2O2 decomposition and slower H2O2 hydrogenation reactions, prevailing under the different reaction conditions, has also been discussed. (C) 2007 Elsevier B.V. All rights reserved.
Keywords: decomposition of H2O2; halide anions as catalyst promoter or indicator; Hydrogen peroxide; hydrogenation of H2O2; Pd/Al2O3

Density functional static dipole polarizability and first-hyperpolarizability calculations of Na-n (n=2, 4, 6, 8) clusters using an approximate CPKS method and its comparison with MP2 calculations - Sophy, K. B.; Calaminici, Patrizia; Pal, Sourav (Journal of Chemical Theory and Computation, 2007)
{We report the static dipole polarizability and first-hyperpolarizability of the sodium atom clusters, Na-n