01795nas a2200277 4500008004100000022001400041245011700055210006900172260006900241300001400310490000800324520078600332653002101118653001401139653001501153653003001168653004301198653002201241100002001263700001901283700002601302700002301328700002601351700001501377856012501392 2005 eng d a0022-328X00aSynthesis, structure, electrochemistry and ROMP-activity of new ferrocenyl analog of Grubbs' metathesis catalyst0 aSynthesis structure electrochemistry and ROMPactivity of new fer aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcFEB a1018-10270 v6903 a

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.

10aElectrochemistry10aferrocene10aMetathesis10anon-covalent interactions10aring-opening metathesis polymerization10aruthenium carbene1 aMaishal, T., K.1 aMondal, Biplab1 aPuranik, Vedavati, G.1 aWadgaonkar, P., P.1 aLahiri, Goutam, Kumar1 aSarkar, A. uhttps://library.ncl.res.in/content/synthesis-structure-electrochemistry-and-romp-activity-new-ferrocenyl-analog-grubbs-101985nas a2200253 4500008004100000022001400041245011600055210006900171260007300240300001200313490000800325520103000333653002401363653002401387653002701411653001101438653002801449100001901477700003501496700003001531700001901561700002601580856012501606 2011 eng d a0926-860X00aSelective hydrogenation of chloronitrobenzenes with an MCM-41 supported platinum allyl complex derived catalyst0 aSelective hydrogenation of chloronitrobenzenes with an MCM41 sup aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAY a117-1250 v3993 a

A platinuin precatalyst (1) has been prepared by reacting [(eta(3)-C3H5)(4)Pt4Cl4] with surface functionalized MCM-41 with pendant -(CH2)(3)NH(CH2)(2)NH2 groups. For the hydrogenation of o-, m- and p-chloronitrobenzenes to the corresponding chloroanilines, 1 is found to be a highly active catalyst with good selectivities for them-and p-isomers. Its performance is superior to that of its palladium analogue and far superior to that of commercial (5%) Pt/C or (5%) Pt/Al2O3. Comparison of solid state and solution NMR data and other evidences indicate that on treatment with the functionalized MCM-41 support; [(eta(3)-C3H5)(4)Pt4Cl4] loses the ally! ligand. XPS data show that in the fresh catalyst Pt is present in the 2+ oxidation state. Based on these and analytical data, co-ordination by surface diamine and hydroxo groups to Pt2+ in 1 is suggested. In the used catalyst both Pt2+ and Pt are present but the amount of metallic platinum is similar to 16% of the total. (C) 2011 Elsevier B.V. All rights reserved.

10aChloronitrobenzenes10aDehydrohalogenation10aheterogeneous catalyst10aMCM-4110aSelective hydrogenation1 aIndra, Arindam1 aRajamohanan, Pattuparambil, R.1 aGopinath, Chinnakonda, S.1 aBhaduri, Sumit1 aLahiri, Goutam, Kumar uhttps://library.ncl.res.in/content/selective-hydrogenation-chloronitrobenzenes-mcm-41-supported-platinum-allyl-complex-002320nas a2200205 4500008004100000245013500041210006900176260000800245300001400253490000700267520154800274100001801822700003101840700001801871700002201889700002601911700001901937700002601956856013201982 2012 eng d00aSelective recognition of fluoride and acetate by a newly designed ruthenium framework: experimental and theoretical investigations0 aSelective recognition of fluoride and acetate by a newly designe cFEB a4484-44960 v413 a

{An effective anion sensor, [Ru-II(bpy)(2)(H2L-)](+) (1(+)), based on a redox and photoactive {Ru-II(bpy)(2)} moiety and a new ligand (H3L = 5-(1H-benzo[d]imidazol-2-yl)-1H-imidazole-4-carboxylic acid), has been developed for selective recognition of fluoride (F-) and acetate (OAc-) ions. Crystal structures of the free ligand, H3L and [1](ClO4) reveal the existence of strong intramolecular and intermolecular hydrogen bonding interactions. The structure of [1](ClO4) shows that the benzimidazole N-H of H2L- is hydrogen bonded with the pendant carboxylate oxygen while the imidazole N-H remains free for possible hydrogen bonding interaction with the anions. The potential anion sensing features of 1(+) have been studied by different experimental and theoretical (DFT) investigations using a wide variety of anions, such as F-, Cl-, Br-, I-, HSO4-, H2PO4-, OAc- and SCN-. Cyclic voltammetry and differential pulse voltammetry established that 1(+) is an excellent electrochemical sensor for the selective recognition kof F- and OAc- anions. 1(+) is also found to be a selective colorimetric sensor for F- or OAc- anions where the MLCT band of the receptor at 498 nm is red shifted to 538 nm in the presence of one equivalent of F- or OAc- with a distinct change in colour from reddish-orange to pink. The binding constant between 1(+) and F- or OAc- has been determined to be logK = 7.61 or 7.88, respectively, based on spectrophotometric titration in CH3CN. The quenching of the emission band of 1(+) at 716 nm (lambda(ex) = 440 nm

1 aKundu, Tanaya1 aChowdhury, Abhishek, Dutta1 aDe, Dipanwita1 aMobin, Shaikh, M.1 aPuranik, Vedavati, G.1 aDatta, Anindya1 aLahiri, Goutam, Kumar uhttps://library.ncl.res.in/content/selective-recognition-fluoride-and-acetate-newly-designed-ruthenium-framework-experimental-003344nas a2200241 4500008004100000022001400041245016200055210006900217260011000286300001600396490000700412520235500419100001802774700002402792700002102816700002502837700001702862700002202879700002602901700001902927700002602946856013002972 2012 eng d a1477-922600aStrong metal-metal coupling in mixed-valent intermediates [Cl(L)Ru(mu-tppz)Ru(L)Cl](+), L = beta-diketonato ligands, tppz=2,3,5,6-tetrakis(2-pyridyl)pyrazine0 aStrong metalmetal coupling in mixedvalent intermediates ClLRumut aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcSEP a13429-134400 v413 a

Five diruthenium(II) complexes [Cl(L)Ru(mu-tppz)Ru(L)Cl](1-5) containing differently substituted beta-diketonato derivatives (1: L = 2,4-pentanedionato; 2: L = 3,5-heptanedionato; 3: L = 2,2,6,6-tetramethyl-3,5-heptanedionato; 4: L = 3-methyl-2,4-pentanedionato; 5: L = 3-ethyl-2,4-pentanedionato) as ancillary ligands (L) were synthesized and studied by spectroelectrochemistry (UV-Vis-NIR, electron paramagnetic resonance (EPR)). X-ray structural characterisation revealed anti (1, 2, 5) or syn (3) configuration as well as non-planarity of the bis-tridentate tppz bridge and strong d pi(Ru-II) -> pi*(pyrazine, tppz) back-bonding. The widely separated one-electron oxidation steps, (RuRuII)-Ru-II/(RuRuIII)-Ru-II and (RuRuIII)-Ru-II/(RuRuIII)-Ru-III, result in large comproportionation constants (K-c) of >= 10(10) for the mixed-valent intermediates. The syn-configurated 3(n) exhibits a particularly high K-c of 10(12) for n = 1+, accompanied by density functional theory (DFT)-calculated minimum Ru-N bond lengths for this (RuRuIII)-Ru-II intermediate. The electrogenerated mixed-valent states 1(+)-5(+) exhibit anisotropic EPR spectra at 110 K with average values < g > of 2.304-2.234 and g anisotropies Delta g = g(1)-g(3) of 0.82-0.99. Metal-to-metal charge transfer (MMCT) absorptions occur for 1(+)-5(+) in the NIR region at 1660 nm-1750 nm (epsilon approximate to 2700 dm(3) mol(-1) cm(-1), Delta nu(1/2) approximate to 1800 cm(-1)). DFT calculations of 1(+) and 3(+) yield comparable Mulliken spin densities of about 0.60 for the metal ions, corresponding to valence-delocalised situations (Ru-2.5)(2). Rather large spin densities of about -0.4 were calculated for the tppz bridges in 1(+) and 3(+). The calculated electronic interaction values (V-AB) for 1(+)-5(+) are about 3000 cm(-1), comparable to that for the Creutz-Taube ion at 3185 cm(-1). The DFT calculations predict that the (RuRuIII)-Ru-III forms in 12(+)-52(+) prefer a triplet (S = 1) ground state with Delta E (S = 0 - S = 1) similar to 5000 cm(-1). One-electron reduction takes place at the tppz bridge which results in species [Cl(L)Ru-II(mu-tppz(.-)) Ru-II(L)Cl](-) (1(.-)-3(.-), 5(.-)) which exhibit free radical-type EPR signals and NIR transitions typical of the tppz radical anion. The system 4(n) is distinguished by lability of the Ru-Cl bonds.

1 aKundu, Tanaya1 aSchweinfurth, David1 aSarkar, Biprajit1 aMondal, Tapan, Kumar1 aFiedler, Jan1 aMobin, Shaikh, M.1 aPuranik, Vedavati, G.1 aKaim, Wolfgang1 aLahiri, Goutam, Kumar uhttps://library.ncl.res.in/content/strong-metal-metal-coupling-mixed-valent-intermediates-cllrumu-tppzrulcl-l-beta-diketonato