@article { ISI:000233927900005, title = {Synthesis, characterization and catalytic application of Ru-II-ethylenediamine complex - mesoporous silica as heterogeneous catalyst system in chemo-selective hydrogenation of alpha,beta-unsaturated carbonyl compounds}, journal = {Microporous and Mesoporous Materials}, volume = {87}, number = {1}, year = {2005}, month = {DEC}, pages = {33-44}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

An efficient heterogeneous catalyst system for chemo-selective hydrogenation of alpha,beta-unsaturated aldehydes was synthesized, involving anchoring of a Ru-II-phosphine complex on the inner surfaces of organo-functionalized (propylamine and propylethylenediamine) mesoporous MCM-41 and MCM-48 materials. Powder XRD, SEM and TEM experiments reveal highly ordered hexagonal and cubic patterns of the organically modified MCM-41 and MCM-48 materials, respectively, even after incorporation of Ru complexes. Moreover, the integrity of the Ru complex was retained after anchoring into the mesoporous hosts, which was supported by FTIR, P-31 CP MAS NMR and XPS analyses. This heterogeneous catalyst shows promising activity and chemo-selectivity towards hydrogenation of carbonyl groups in alpha,beta-unsaturated aldehydes. The effects of reaction temperature, reaction time and hydrogen pressure on the activity and selectivity were studied in detail. The anchored solid catalysts can be recycled effectively and reused several times without any loss in activity and selectivity. Although, the initial activity of the same Ru complex when grafted onto the organically modified surfaces of fumed silica is comparable to corresponding MCM41/MCM-48 catalysts, the activity and chemo-selectivity significantly decrease during recycle of the catalyst due to leaching. (c) 2005 Elsevier Inc. All rights reserved.

}, keywords = {chemo-selective, heterogeneous catalysis, Heterogenization, Hydrogenation, mesoporous materials, organo-functionalization, Ru-II-ethylenediamine complex, unsaturated aldehyde}, issn = {1387-1811}, doi = {10.1016/j.micromeso.2005.06.042}, author = {Ghosh, Anirban and Kumar, R} } @article { ISI:000254872600028, title = {Heteropoly acid encapsulated SBA-15/TiO(2) nanocomposites and their unusual performance in acid-catalysed organic transformations}, journal = {Chemistry-A European Journal}, volume = {14}, number = {10}, year = {2008}, month = {FEB}, pages = {3200-3212}, publisher = {WILEY-BLACKWELL}, type = {Article}, address = {COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA}, abstract = {

The preparation of SBA-15/TiO(2) nanocomposites with different loadings of Keggin-type 12-tungsto-phosphoric acid (TPA) nanocrystals in their mesochannels through a simple and effective vacuum impregnation method is reported for the first time. The catalysts have been characterised by various sophisticated techniques, including XRD, HRSEM, and TEM. It has been found that the acidity and the textural parameters of the nanocomposites can be controlled by simply changing the loadings of TPA and TiO(2) or the calcination temperature. TPA and TiO(2) loadings of 15 and 22.4 wt \%, respectively, and a calcination temperature of 1123 K have proved to be optimal for obtaining mesoporous nanocomposite materials with the highest acidity. Moreover, the activities of these catalysts in promoting hydroamination as well as Mannich and Claisen rearrangement reactions have been extensively investigated. The results show that the amount of TPA has a great influence on the activity of the nanocomposites in all of the reactions studied. The effects of other reaction parameters, such as temperature and reaction time, on the conversion and product selectivity have also been studied in detail. A kinetic analysis of the formation of the products under various reaction conditions is presented. It has been found that the activity of the nanocomposite composed of 15 wt \% TPA deposited on 22.4 wt of TiO(2) on SBA-15 in promoting the studied reaction is remarkably higher than the catalytic activities shown by pure TPA, TiO(2)-loaded SBA-15, or TPA-loaded SBA-15. The results obtained have indicated that the acidity and the structural control of the nanocomposite materials are highly critical for obtaining excellent catalytic activity, and the presented highly acidic nanocomposites are considered to show great potential for use as catalysts in promoting many acid-catalysed organic transformations.

}, keywords = {Bronsted acids, mesoporous materials, nanoreactors, nanotechnology, supported catalysts}, issn = {0947-6539}, doi = {10.1002/chem.200701562}, author = {Sawant, Dhanashri P. and Justus, Josena and Balasubramanian, Veerappan V. and Ariga, Katsuhiko and Srinivasu, Pavuluri and Velmathi, Sivan and Halligudi, Shivappa B. and Vinu, Ajayan} } @article { ISI:000258108200006, title = {Studies in structural characterization and correlation with the catalytic activity of an efficient and stable WOx/SBA-15 nanocomposite catalyst}, journal = {Journal of Catalysis}, volume = {257}, number = {2}, year = {2008}, month = {JUL}, pages = {283-290}, publisher = {ACADEMIC PRESS INC ELSEVIER SCIENCE}, address = {525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA}, abstract = {

A new WOx/SBA-15 nanocomposite catalyst system was developed by hydrothermal synthesis. The material was characterized by X-ray diffraction, high-resolution transmission electron microscopy, sorption analysis, FT-IR, CP-MAS NMR, XPS, and energy-dispersive X-ray analysis. Various types of aromatic and aliphatic sulfides were selectively oxidized to sulfoxides in good to excellent yields without becoming overoxidized to the sulfones using 70\% aq. tert-butyl hydrogen peroxide in the presence of nanocomposite catalyst at room temperature. The catalyst could be easily recovered and reused for at least eight reaction cycles under the reaction conditions described here with no significant loss of reactivity. (c) 2008 Elsevier Inc. All rights reserved.

}, keywords = {catalytic oxidation, mesoporous materials, Sulfides, Sulfoxides, tungsten oxide nanocluster}, issn = {0021-9517}, doi = {10.1016/j.jcat.2008.05.015}, author = {Bordoloi, Ankur and Halligudi, Shivaraj B.} } @article { ISI:000261329400004, title = {Synthesis, characterization and catalytic activity of Sn-SBA-15 mesoporous molecular sieves}, journal = {Catalysis Surveys from Asia}, volume = {12}, number = {4}, year = {2008}, month = {DEC}, pages = {283-309}, publisher = {SPRINGER/PLENUM PUBLISHERS}, type = {Article}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Our recent reports on the synthesis of Sn-incorporated mesoporous SBA-15 materials have been reviewed. The preparation of the samples with different Si/Sn ratios followed two procedures, the first is the post-synthesis modification of SBA-15 by impregnation with Sn chloride or acetate, and the second is the direct method in which Sn chloride was introduced in to Si precursor along with amphiphilic triblock copolymer, while varying the ratio of the synthesis gel. Detailed characterization of the Sn-SBA-15 samples by a variety of techniques shows how the synthesis procedures influence the properties of the samples that reflect on the differences in (a) the structural features, (b) morphology and textural properties, such as the pore characteristics, (c) the possible location of Sn4+ ions in the meso silica structure and their reducibility, (d) the nature of the Sn species and their the coordination sphere and (e) the acid-base characteristics. We developed a possible model for the localization of Sn species in SBA-15 pore structure for different conditions of preparation. This report includes our investigations on the catalytic properties of these Sn-SBA-15 samples in 3 industrially important reactions, viz., trans-esterification of diethyl malonate, synthesis of nopol by Prins condensation of beta-pinene with para-formaldehyde and the epoxidation of norbornene. In each of this reaction, while demonstrating the catalytic role of Sn species, we show that the requirement of the type and the environment of Sn species are different for these reactions.

}, keywords = {mesoporous materials, Properties of Sn-SBA-15, Sn-containing SBA-15, Sn-SBA-15 catalysts, Synthesis of Sn-SBA-15}, issn = {1571-1013}, doi = {10.1007/s10563-008-9060-6}, author = {Ramaswamy, Veda and Shah, Pallavi and Lazar, Karoly and Ramaswamy, A. V.} } @article { ISI:000284052600021, title = {Covalently immobilized triphenylphosphine rhodium complex: synthesis, characterization, and application in catalytic olefin hydrogenation}, journal = {Chemcatchem}, volume = {2}, number = {11}, year = {2010}, month = {NOV}, pages = {1477-1482}, publisher = {WILEY-BLACKWELL}, address = {COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA}, abstract = {

A trimethoxysilane functionalized triphenylphosphine was coordinated to rhodium(I) and the resulting rhodium complex was covalently bound to a mesoporous SBA-15 support. The catalytic activity of this hybrid material was studied for the hydrogenation of 2-cyclohexen-1-one and compared with the corresponding homogeneous catalyst. According to the (31)P-MAS NMR data, the catalytically active species was stable against oxidation; no structural change could be detected after exposing it to air for more than two months. Transmission electron microscopy (TEM) measurements on the used catalyst confirmed that the rhodium species was also stable against reduction to the metal because the formation of rhodium nanoparticles during the catalysis could be excluded. The kinetic curves of the recycled system confirmed that this hybrid catalyst shows excellent activity, selectivity, stability, and reusability, and is truly heterogeneous in the hydrogenation reaction.

}, keywords = {alkenes, heterogeneous catalysis, Hydrogenation, mesoporous materials, Rhodium}, issn = {1867-3880}, doi = {10.1002/cctc.201000133}, author = {Wang, Lei and Jia, Mingjun and Shylesh, Sankaranarayanapillai and Philippi, Thomas and Seifert, Andreas and Ernst, Stefan and Singh, Anand Pal and Thiel, Werner R.} } @article { ISI:000284814600017, title = {Efficient heterogeneous catalytic system for chemoselective hydrogenation of unsaturated ketones in aqueous medium}, journal = {Polyhedron}, volume = {29}, number = {17}, year = {2010}, month = {NOV}, pages = {3262-3268}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A highly chemoselective and green heterogeneous catalytic system of immobilized Ru(II)-phenanthroline complexes on amino functionalised MCM-41 material for the chemoselective hydrogenation of unsaturated ketones to unsaturated alcohols is demonstrated using water as a solvent The XRD and FTIR spectra show the highly ordered hexagonal nature of the MCM-41 even after encapsulation of the ruthenium complex The complex retains its configuration after anchoring as was confirmed by FTIR and UV-Vis analysis The detailed reaction parametric effect was studied for the hydrogenation of 3 methylpent-3-en-2-one to achieve complete conversion up to \>99\% chemoselectivity of 3-methylpent-3-en-2 ol The anchored heterogeneous catalysts were recycled effectively and reused five times with marginal changes in activity and selectivity The use of water as a solvent not only afforded high activity for the hydroge nation reaction compared to organic solvents but also afforded a green process Crown Copyright (C) 2010 Published by Elsevier Ltd All rights reserved

}, keywords = {1 10 Phenanthroline, alpha beta Unsaturated ketone, Chemoselective hydrogenation, mesoporous materials, ruthenium}, issn = {0277-5387}, doi = {10.1016/j.poly.2010.09.006}, author = {Deshmukh, Amit A. and Kinage, Anil K. and Kumar, Rajiv and Meijboom, Reinout} } @article { ISI:000273933800010, title = {Heterogenized copper catalysts for the amination of arylhalide: synthesis, characterization and catalytic applications}, journal = {Applied Catalysis A-General}, volume = {372}, number = {1}, year = {2010}, month = {JAN}, pages = {73-81}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

This research investigated the synthesis, characterization and catalytic activity of heterogenized copper complexes for the selective amination of aryl halides. Amination reactions using homogeneous copper catalyst systems are not generally selective and it is also difficult to recover the catalyst from the homogeneous system for recycling. To overcome these difficulties, our efforts were directed towards the development of cheaper heterogeneous catalyst systems, which can be easily recovered and recycled. Heterogenized analogs of the homogenous Cu complexes were prepared using two methods: (a) encapsulation of copper complexes in zeolite-Y and (b) tethering of copper complexes on various supports like zeolite-Y, silica, charcoal, or clay. The encapsulated and tethered copper catalysts on zeolite-Y were characterized using EPR, Diffused reflectance UV-vis, XRD, IAS, ICPES, SEM, and TEM. The results confirmed that the copper complexes were truly heterogenized in zeolite-Y support. Encapsulated and tethered copper complexes were tested for amination of aryl iodide. The effects of various reaction parameters were examined using tethered Cu(Phen)(PPh(3))Br-PTA-Y catalyst to determine optimum conditions. A recycle study of encapsulated and tethered Cu catalyst was carried out to test their robustness for possible commercial exploitation. (C) 2009 Elsevier B.V. All rights reserved.

}, keywords = {Amination, C-N coupling, Copper, heterogeneous catalysis, mesoporous materials}, issn = {0926-860X}, doi = {10.1016/j.apcata.2009.10.013}, author = {Patil, Nandkumar M. and Gupte, Sunil P. and Chaudhari, Raghunath V.} } @article { ISI:000290841300030, title = {Immobilization of 1,5,7-triazabicyclo [4.4.0] dec-5-ene over mesoporous materials: an efficient catalyst for michael-addition reactions under solvent-free condition}, journal = {Applied Catalysis A-General}, volume = {397}, number = {1-2}, year = {2011}, month = {APR}, pages = {250-258}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Immobilization of 1,5,7-triazabicyclo [4.4.0] dec-5-ene (TBD, a bicylic guanidine base) over mesoporous material like SBA-15 has been found to be an excellent catalyst for Michael-addition of beta-nitro styrene with malonate. The reactions were performed under solvent-free condition at 373 K for 9 h. A wide variety of Michael donors and acceptors were investigated. Among them, high yield of Michael product was obtained for the reaction between p-Cl-nitrostyrene with dimethyl malonate. (C) 2011 Elsevier B.V. All rights reserved.

}, keywords = {1, 5, 7-triazabicyclo[4.4.0] dec-5-ene, beta-nitro styrene and malonate, mesoporous materials, Michael-addition}, issn = {0926-860X}, doi = {10.1016/j.apcata.2011.03.010}, author = {Kalita, Pranjal and Kumar, Rajiv} } @article { ISI:000311350000022, title = {Anchored Pd-complexes in mesoporous supports: synthesis, characterization and catalysis studies for carbonylation reactions}, journal = {Catalysis Today}, volume = {198}, number = {1, SI}, year = {2012}, month = {DEC}, pages = {154-173}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Pd(pyca)(PPh3)(OTs) [pyca = 2-picolinate] complex is efficiently anchored inside different mesoporous matrices, such as MCM-41, MCM-48, SBA-15 using a molecular aminopropyl tether moiety employing different synthesis strategies. Thorough characterization of the materials using powder XRD, multinuclear (C-13, Si-29, P-31) CP-MAS NMR, XPS, SEM, N-2-sorption studies etc. confirmed the successful anchoring of the palladium complex to the walls of the support matrices thus establishing the synthesis protocols unambiguously. The catalysts were found to be highly active and selective for the carbonylation of different aryl olefins and alcohols. Consecutive recycling and successful reuse proved the stability and true heterogeneous nature of all the anchored catalysts, which is a substantial advancement over the existing heterogeneous catalysts for carbonylation. (C) 2012 Elsevier B. V. All rights reserved.

}, keywords = {Anchored catalysts, Carbonylation, Immobilization, mesoporous materials, Palladium complex}, issn = {0920-5861}, doi = {10.1016/j.cattod.2012.04.047}, author = {Sarkar, Bibhas R. and Chaudhari, Raghunath V.} } @article { ISI:000311350000009, title = {Selective oxidation of cyclic olefins over framework Ti-substituted, three-dimensional, mesoporous Ti-SBA-12 and Ti-SBA-16 molecular sieves}, journal = {Catalysis Today}, volume = {198}, number = {1, SI}, year = {2012}, month = {DEC}, pages = {59-68}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Framework Ti-substituted, three-dimensional, mesoporous titanosilicates, Ti-SBA-12 and Ti-SBA-16, were prepared by direct hydrothermal synthesis method. These catalysts showed catalytic activity higher than the hitherto known titanosilicates for the oxidation of cyclic olefins (cyclohexene and cyclooctene) with tert.-butyl hydroperoxide. An epoxide selectivity of 100\% and olefin conversion greater than 92\% were obtained. Cubic Ti-SBA-16 with interconnected cage-like mesopore structure was more active than hexagonal Ti-SBA-12. X-ray diffraction and diffuse reflectance UV-vis, Fourier transform infrared, Raman and electron paramagnetic resonance spectroscopies provided evidence for the substitution of Ti4+ (for Si4+) in the framework locations. The catalytic activity correlated with the concentration of framework-substituted, tetrahedral Ti4+ ions. Easy accessibility of the active sites and the three-dimensional mesoporous structure are the possible causes for the superior activity of these titanosilicate catalysts. (C) 2012 Elsevier B. V. All rights reserved.

}, keywords = {Epoxidation of cyclic olefins, mesoporous materials, Molecular sieves, Selective oxidation, Ti-SBA-12, Ti-SBA-16, Titanosilicates}, issn = {0920-5861}, doi = {10.1016/j.cattod.2012.01.035}, author = {Kumar, Anuj and Srinivas, Darbha} } @article { ISI:000327410300055, title = {Enhancement of chemical stability and crystallinity in porphyrin-containing covalent organic frameworks by intramolecular hydrogen bonds}, journal = {Angewandte Chemie-International Edition}, volume = {52}, number = {49}, year = {2013}, month = {DEC}, pages = {13052-13056}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, keywords = {covalent organic frameworks, hydrogen bonds, mesoporous materials, porphyrinoids, tautomerism}, issn = {1433-7851}, doi = {10.1002/anie.201306775}, author = {Kandambeth, Sharath and Shinde, Digambar Balaji and Panda, Manas K. and Lukose, Binit and Heine, Thomas and Banerjee, Rahul} } @article { ISI:000323361600008, title = {Three-dimensional, mesoporous titanosilicates as catalysts for producing biodiesel and biolubricants}, journal = {Journal of Molecular Catalysis A-Chemical}, volume = {377}, year = {2013}, month = {OCT}, pages = {65-73}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The application of three-dimensional, mesoporous titanosilicates, Ti-SBA-12 and Ti-SBA-16, as reusable solid acid catalysts for producing biodiesel and biolubricants is reported for the first time. Biodiesel was prepared by esterification of oleic acid with monohydric methanol and biolubricants by esterification with polyhydric alcohols (glycerol, trimethylolpropane, neopentyl glycol and pentaerythritol). High catalytic activity of these catalysts is attributed to the presence of dispersed Lewis acidic Ti sites and mesoporosity in the structure. Biodiesel yields as high as 90 mol\% were obtained at 443 K. Surface hydrophobicity of the catalyst has also a predominant role, especially, in reactions involving polyhydric alcohols. In those reactions, Ti-SBA-16 showed higher catalytic activity than Ti-SBA-12. (c) 2013 Elsevier B.V. All rights reserved.

}, keywords = {Biodiesel, Esterification of fatty acid, Lubricant basestocks, mesoporous materials, Ti-SBA-12, Ti-SBA-16, Titanosilicates}, issn = {1381-1169}, doi = {10.1016/j.molcata.2013.04.029}, author = {Kotwal, Mehejabeen and Kumar, Anuj and Darbha, Srinivas} } @article { ISI:000344330800010, title = {Acid-base cooperative catalysis over mesoporous nitrogen-rich carbon}, journal = {ChemCatChem}, volume = {6}, number = {11}, year = {2014}, month = {NOV}, pages = {3091-3095}, publisher = {WILEY-V C H VERLAG GMBH}, type = {Article}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

WOx nanoclusters (2-3 nm) embedded on a mesoporous nitrogen-rich carbon material were synthesized by using novel methodology. This material was very effectively capitalized as a new carbon-based acid-base cooperative catalyst for sequential acetal hydrolysis and Knoevenagel condensation reactions. The protocol was also explored for the nitroaldol condensation reaction.

}, keywords = {cooperative catalysts, Knoevenagel condensation, mesoporous materials, Nanostructures, nitro aldol reaction}, issn = {1867-3880}, doi = {10.1002/cctc.201402537}, author = {Goyal, Reena and Sarkar, Bipul and Lucas, Nishita and Bordoloi, Ankur} } @article { ISI:000337637100017, title = {Disordered mesoporous TiO2-xNx+Nano-Au: an electronically integrated nanocomposite for solar H-2 generation}, journal = {ChemCatChem}, volume = {6}, number = {2}, year = {2014}, month = {FEB}, pages = {522-530}, publisher = {WILEY-V C H VERLAG GMBH}, type = {Article}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

We report on H-2 generation by photocatalysis driven by simulated white light by electronically integrated Au nanoparticles with multifunctional, disordered mesoporous TiO2-xNx (Au-NT) nanocomposites. Solar H-2 generation (1.5 mmolh(-1)g(-1)) from aqueous methanol has been demonstrated with Au-NT nanocomposites. The water splitting activity of Au-NT is attributed to the 21.1 ps lifetime of charge carriers observed from fluorescence lifetime measurements, which indicates a high electron-injection efficiency from nano-Au to the conduction band of TiO2, and hence charge separation as well as utilization. This is directly supported by the observation of a high photoluminescence emission intensity with Au-NT that highlights the energy transfer from nano-Au to TiO2. The p-n heterojunction observed between the Au (001) and TiO2 (101) facets helps to-wards the higher charge separation and their utilization. A low mesochannel depth (\< 10 nm) associated with disordered mesoporous TiO2-xNx helps the charge carriers to move towards the surface for redox reactions and hence charge utilization. Visible-light absorption, as a result of the surface plasmon resonance of nano-Au, is observed in a broad range between 500 and 750 nm, which helps in harvesting visible-light photons. Finally, electronically integrated nano-Au with TiO2-xNx in Au-NT is evident from Raman and X-ray photoelectron spectroscopy measurements. All of these factors help to achieve a high rate of H-2 production. It is likely that a higher rate of H-2 production than that reported here is feasible by strategically locating Au clusters in porous TiO2 to generate hot spots through electronic integration.

}, keywords = {heterogeneous catalysis, Hydrogen, mesoporous materials, photochemistry, water splitting}, issn = {1867-3880}, doi = {10.1002/cctc.201300715}, author = {Sivaranjani, Kumarsrinivasan and Rajaambal, Sivaraman and Das, Tanmay and Roy, Kanak and Bhattacharyya, Somnath and Gopinath, Chinnakonda S.} } @article { ISI:000345975300012, title = {Titania nanoparticles stabilized HPA in SBA-15 for the intermolecular hydroamination of activated olefins}, journal = {ChemCatChem}, volume = {6}, number = {12}, year = {2014}, month = {DEC}, pages = {3347-3354}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

A liquid phase hydroamination (HA) of alpha,beta-ethylenic compounds with amines was investigated with TiO2 nanoparticles stabilized 12-tungstophosphoric acid (TPA) in SBA-15. The catalysts were prepared by wet impregnation of TPA/TiO2 nanoparticles into the SBA-15 and calcined at different temperatures. The characterization results reveal that the textural properties and the acidity of the prepared catalysts can be finely controlled with the simple adjustment of the calcination temperature and the structure of the support, decorated with the TiO2 and TPA nanoparticles, was intact even after the modification. The prepared catalysts were investigated for HA of ethyl acrylate with different aromatic and aliphatic amines over a wide range of reaction conditions to optimize the yield and the selectivity of product. It was found that this process is 100\% atom efficient and the catalytic performance depended significantly on the loading of TPA over the catalyst and the calcination temperature. Under optimized reaction conditions, the best catalyst, 15 wt\% TPA/22.4 wt\% TiO2/SBA-15 calcined at 1123 K, offered the highest conversion of p-ethylaniline (70\%) with 100\% chemo-selectivity to the anti-Markovnikov product, i.e., the mono-addition product. The reaction was heterogeneously catalyzed and no contribution from leached TPA into the reaction was observed.

}, keywords = {heteropoly acids, hydroamination, mesoporous materials, nanocatalysts}, issn = {1867-3880}, doi = {10.1002/cctc.201402449}, author = {Sawant-Dhuri, Dhanashri and Balasubramanian, Veerappan V. and Ariga, Katsuhiko and Park, Dae-Hwan and Choy, Jin-Ho and Cha, Wang Soo and Al-deyab, Salem S. and Halligudi, Shivappa B. and Vinu, Ajayan} } @article {45761, title = {Synthesis and characterization of D-2PA-Pd(II)@SBA-15 catalyst via {\textquoteleft}{\textquoteleft}click chemistry{\textquoteright}{\textquoteright}: highly active catalyst for Suzuki coupling reactions}, journal = {Journal of Porous Materials}, volume = {24}, year = {2017}, month = {APR}, pages = {327-340}, type = {Article}, abstract = {

Copper catalysed cycloaddition reaction between azide and terminal alkyne, called as {\textquoteleft}{\textquoteleft}click reaction{\textquoteright}{\textquoteright}, was found to be modular approach for the synthesis of facile, highly efficient and recoverable D-2PA-Pd(II)@SBA-15 catalyst. In efforts to synthesize the catalyst, the cycloaddition reaction between azido-functionalized mesoporous SBA-15 and N,N-dimethyl-2-propynylamine (D-2PA) has been carried out, followed by the complexation with PdCl2. To analyze physiochemical properties of synthesized materials, various characterization techniques such as CHN elemental analysis, X-ray diffraction, solid state C-13 and Si-29 NMR spectra, FT-IR, XPS, SEM, TEM and N-2 sorption analysis, TGA and DTA, UV-Vis spectroscopy have been carried out. The synthesized catalyst, D-2PA-Pd(II)@SBA-15, exhibited excellent catalytic activities with good product yield and high TON towards Suzuki coupling reaction of various aryl halides with phenylboronic acid. The effect of solvent, base and temperature on coupling reactions has also been described. The developed protocol offers recyclability of catalyst for multiple (four) times without any appreciable loss in stability and catalytic reactivity.

}, keywords = {Click reaction, Cycloaddition, mesoporous materials, SBA-15, Suzuki coupling}, issn = {1380-2224}, doi = {10.1007/s10934-016-0266-0}, author = {Pathak, Aruna and Singh, A. P.} } @article {47377, title = {Solvent free, environment benign synthesis of 1,4-dihydropyridines and polyhydroquinolines by using heterogeneous Zn/MCM-41 catalyst}, journal = {Research on Chemical Intermediates}, volume = {47}, year = {2021}, month = {AUG}, pages = {3263-3287}, type = {Article}, abstract = {

Heterogeneous catalysis has been utilized in number of efficient reactions with higher selectivity of the product, more stable, reusable and easy for separation as compared to homogeneous catalysts. Generally, heterogeneous catalysts are prepared by using mesoporous materials, microporous materials, metal oxides and metal organic framework. The mesoporous materials have small particle size and high surface area as compared to the microporous materials. The adsorbent mesoporous materials have highly efficient for the therapeutic applications in chemistry hence it has best as compared to other heterogeneous materials. Herein, we have reported synthesis of 1,4-dihydropyridines and polyhydroquinolines at solvent free and environmental benign condition in the presence of Zn/MCM-41 catalyst. The present protocol gives excellent yield (89-96\%) of the product within short reaction time by easy work up procedure and no need of further purification of product. The catalyst was characterized by XRD diffractometer, SEM, EDAX, TGA-DTA, BET surface area analysis and FT-IR Spectroscopy. The synthesized organic compounds were characterized by FT-IR, H-1 NMR, C-13 NMR, LC-MS spectrometry.

}, keywords = {High activity, High selectivity, mesoporous materials, microporous materials, Reusability of catalyst}, issn = {0922-6168}, doi = {10.1007/s11164-021-04473-z, Early Access Date = APR 2021}, author = {Dhengale, Shankar D. and Naik, Vaibhav M. and Kolekar, Govind B. and Rode, Chandrashekhar V. and Anbhule, Prashant V.} } @article {48287, title = {Robust optimization and characterization of MCM-41 nanoparticle synthesis using modified sol-gel method}, journal = {ChemistrySelect}, volume = {8}, year = {2023}, month = {MAR}, pages = {e202204968}, type = {Article}, abstract = {

Mesoporous silica nanoparticles (MSN) for drug delivery application requires great expertise to synthesize small sized monodisperse particles. We aimed at synthesizing and optimizing MCM-41 particles with the modified Stober{\textquoteright}s method by adjusting factors such as concentrations of cetyltrimethylammonium bromide (CTAB), sodium hydroxide (NaOH) and water (H2O) with respect to tetraethyl orthosilicate (TEOS), and a process parameter (stirring). We comprehended that the reactants determined the shape and size of both the particles and pores. Upon extensive characterization we report the synthesis of spherical particles of similar to 70 nm size in a monodisperse population; the structures had hexagonal ordered pores of diameter 3.071 nm and volume 3.124 cm(3)/g; the total surface area of 3410.648 m(2)/g of the particles was covered with silanol groups that aid in functionalization; the particles exhibited great thermal stability. Thus, the extensive optimization fabricated robust MCM-41 particles fit for drug delivery application.

}, keywords = {characterization technique, dynamic light scattering (DLS), mesoporous materials, Nanoparticles, sol gel processes}, issn = {2365-6549}, doi = {10.1002/slct.202204968}, author = {Shende, Rajnigandha A. and Chaudhari, Bhushan P.} }