01479nas a2200325 4500008004100000022001400041245025900055210006900314260007700383300001400460490000700474520024200481653002100723653003600744653002100780653000600801653001400807653001400821100001200835700001500847700002100862700001900883700002100902700001700923700002600940700001800966700001900984700002601003856012401029 2005 eng d a0947-653900a2,5-dioxido-1,4-benzoquinonediimine (H2L2-), a hydrogen-bonding noninnocent bridging ligand related to aminated topaquinone: different oxidation state distributions in complexes [{(bpy)(2)Ru}(2)(mu-H2L)](n) (n=0,+,2+,3+,4+) and [{(acac)(2)Ru}(2)(mu-H2L)]0 a25dioxido14benzoquinonediimine H2L2 a hydrogenbonding noninnocen aPO BOX 10 11 61, D-69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcAUG a4901-49110 v113 a

{The symmetrically dinuclear title compounds were isolated as diamagnetic [(bpy)(2)Ru(mu-H2L)Ru(bpy)(2)]- (ClO4)(2) (1-(ClO4)(2)) and as paramagnetic [(acac)(2)Ru(mu-H2L)Ru(acac)(2)] (2) complexes (bpy = 2,2'-bipyridine; acac(-) -

10abridging ligands10aDensity functional calculations10aEPR spectroscopy10aN10aO ligands10aruthenium1 aKar, S.1 aSarkar, B.1 aGhumaan, Sandeep1 aJanardanan, D.1 avan Slageren, J.1 aFiedler, Jan1 aPuranik, Vedavati, G.1 aSunoj, R., B.1 aKaim, Wolfgang1 aLahiri, Goutam, Kumar uhttp://library.ncl.res.in/content/25-dioxido-14-benzoquinonediimine-h2l2-hydrogen-bonding-noninnocent-bridging-ligand-103185nas a2200229 4500008004100000022001400041245025900055210006900314260007100383300001400454490000700468520220000475100001502675700001302690700001202703700002202715700001902737700002602756700001602782700002602798856013102824 2005 eng d a0020-166900aEffect of 2-(2-pyridyl)azole-based ancillary ligands (L1-4) on the electrophilicity of the nitrosyl function in [Ru-II(trpy)(L1-4)(NO)](3+) [trpy=2,2 `: 6 `,2 `'-terpyridine]. synthesis, structures, and spectroscopic, electrochemical, and kinetic aspects0 aEffect of 22pyridylazolebased ancillary ligands L14 on the elect a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAY a3499-35110 v443 a

Ruthenium nitrosyl complexes [Ru(trpy)(L1-4)(NO)](3+) (13-16) [trpy = 2,2':6',2"-terpyridine, L-1 = 2-(2-pyridyl)-benzoxazole, L-2 = 2-(2-pyridyl)benzthiazole, L-3 = 2-(2-pyridyl)benzimidazole, L-4 = 1-methyl-2-(2-pyridyl)-1H-benzimidazole] were obtained in a stepwise manner starting from [Ru-II(trpy)(L1-4) (Cl)]ClO4 (1-4) → [Ru-II(trpy)(L1-4) (H2O)](ClO4)(2) (5-8) → [Ru-II(trpy)(L1-4) (NO2)ClO4 (9-12) → [Ru-II(trpy)(L-1,L-2,L-4) (NO)](ClO4)(3) (13, 14, 16)/[Ru-II(trpy)(L-3) (NO)](Cl)(4))(2)(NO3) (15). Crystal structures of 1, 2, 4, 9, 12, 13, 15, and 16 established the stereoretentive nature of the transformation processes. Though the complexes of L1, L3, and L 4 were isolated in the isomeric form A (π-acceptor trpy and azole ring in the equatorial plane and the pyridine and chloride donors in the axial positions), complexes of L 2 preferentially stabilized in form B (trpy and pyridine in the equatorial plane and the azole ring and chloride donors in the axial positions). The v(NO) stretching frequency varied in the range of 1957-1932 cm(-1), 13 &MGT; 14 &MGT; 15 > 16, primarily depending on the electronic aspects of L as well as the isomeric structural forms. The coordinated nitrosyl function underwent successive reductions of [Ru-II-NO+](3+) → [Ru-II-NO•](2+) and [Ru-II-NO•](2+) - [Ru-II-NO-](+), and the first reduction potential follows the order 14 > 13 &MGT; 15 ≈ 16. The nearly axial EPR spectra having nitrogen hyperfine splittings (A ≈ 26 G) at 77 K of 13(-)-16(-) with (g) ≈ 2.0 established that the reduction process is largely centered around the nitrosyl function. Despite an appreciably high v(NO), the complexes were found to be unusually stable even in the aqueous medium. They transformed slowly and only partially into the corresponding nitro derivatives in H2O (k ≈ 10(-4) s(-1) and K = 0.4-3.8). The chloro (1-4), aqua (5-8), and nitro (9-12) derivatives displayed reasonably strong emissions near 700 nm at 77 K (φ = 10(-1)-10(-2)). The aqua derivative 7 was found to interact with the calf thymus and the circular form of p-Bluescript SK DNA.

1 aChanda, N.1 aPaul, D.1 aKar, S.1 aMobin, Shaikh, M.1 aDatta, Anindya1 aPuranik, Vedavati, G.1 aRao, K., K.1 aLahiri, Goutam, Kumar uhttp://library.ncl.res.in/content/effect-2-2-pyridylazole-based-ancillary-ligands-l1-4-electrophilicity-nitrosyl-function-ru-101385nas a2200241 4500008004100000022001400041245008900055210006900144260009500213300001200308490000800320520046100328653002500789653003600814653002800850653003000878100001700908700001800925700003000943700001900973700002600992856012501018 2005 eng d a0021-951700aMCM-41-supported platinum carbonyl cluster-derived asymmetric hydrogenation catalyst0 aMCM41supported platinum carbonyl clusterderived asymmetric hydro a525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USAbACADEMIC PRESS INC ELSEVIER SCIENCEcJAN a298-3020 v2293 a

Anionic platinum carbonyl cluster has been ion paired with cinchonidium groups that are chemically bound to the surface of MCM-41 and fumed silica. In the hydrogenation of methyl pyruvate or acetophenone the fumed silica-based catalyst gives zero enantioselectivity, but under optimum conditions enantiomeric excesses of >90 and similar to40%, respectively, are obtained with the MCM-41-based catalyst. (C) 2004 Elsevier Inc. All rights reserved.

10aasymmetric catalysis10afunctionalized inorganic oxides10ahydrogenation catalysts10aplatinum carbonyl cluster1 aBasu, Susmit1 aPaul, Himadri1 aGopinath, Chinnakonda, S.1 aBhaduri, Sumit1 aLahiri, Goutam, Kumar uhttp://library.ncl.res.in/content/mcm-41-supported-platinum-carbonyl-cluster-derived-asymmetric-hydrogenation-catalyst-001794nas a2200277 4500008004100000022001400041245011700055210006900172260006900241300001400310490000800324520078600332653002101118653001401139653001501153653003001168653004301198653002201241100002001263700001901283700002601302700002301328700002601351700001501377856012401392 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. uhttp://library.ncl.res.in/content/synthesis-structure-electrochemistry-and-romp-activity-new-ferrocenyl-analog-grubbs-102395nas a2200289 4500008004100000022001400041245025900055210006900314260010600383300001200489490000700501520123700508653002101745653001001766653002401776653001201800653001401812653001401826100001401840700001401854700001501868700002101883700002601904700001901930700002601949856013001975 2005 eng d a0277-538700aTetrazine 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, spectra0 aTetrazine derived mononuclear RuIIacac2L1 RuIIbpy2LClO422 and Ru aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcJAN a333-3420 v243 a

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.

10aElectrochemistry10aredox10aruthenium-tetrazine10aspectra10astructure10asynthesis1 aNayak, A.1 aPatra, S.1 aSarkar, B.1 aGhumaan, Sandeep1 aPuranik, Vedavati, G.1 aKaim, Wolfgang1 aLahiri, Goutam, Kumar uhttp://library.ncl.res.in/content/tetrazine-derived-mononuclear-ru-iiacac2l1-ru-iibpy2lclo422-and-ru-iibpyl2clo423-l3-amino-101994nas a2200229 4500008004100000022001400041245026000055210006900315260007100384300001400455490000700469520099600476100001201472700001501484700002201499700002001521700001701541700002601558700002801584700002601612856012601638 2005 eng d a0020-166900aUnusual monodentate binding mode of 2,2 `-dipyridylamine (L) in isomeric trans(acac)(2)Ru-II(L)2, trans-[(acac)(2)Ru-III(L)(2)]ClO4, and cis-(acac)(2)Ru-II(L)(2) (acac = acetylacetonate). Synthesis, structures, and spectroscopic, electrochemical, and magn0 aUnusual monodentate binding mode of 22 dipyridylamine L in isome a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAR a1571-15790 v443 a

{The reaction of cis-Ru(acac)(2)(CH3CN)(2) (acac = acetylacetonate) with 2,2'-dipyridylamine (L) in ethanolic medium resulted in facile one-pot synthesis of stable [(acac)(2)Ru-III(L)]ClO4 ([1]ClO4), trans-[(acac)(2)Ru-II(L)2] (2), trans[(acac)(2)Ru-III(L)(2)[ClO4 ([2]ClO4), and cis-[(acac)(2)Ru-II(L)(2)] (3). The bivalent congener 1 was generated via electrochemical reduction Of [1]ClO4. Although in [1](+) the dipyridylamine ligand (L) is bonded to the metal ion in usual bidentate fashion, in 2/[2](+) and 3, the unusual monodentate binding mode of L has been preferentially stabilized. Moreover, in 2/[2](+) and 3, two such monodentate L's have been oriented in the trans- and cis-configurations, respectively. The binding mode of L and the isomeric geometries of the complexes were established by their single-crystal X-ray structures. The redox stability of the Ru(II) state follows the order 1 < 2 much less than 3. In contrast to the magnetic moment obtained for [1]ClO4

1 aKar, S.1 aChanda, N.1 aMobin, Shaikh, M.1 aUrbanos, F., A.1 aNiemeyer, M.1 aPuranik, Vedavati, G.1 aJimenez-Aparicio, Reyes1 aLahiri, Goutam, Kumar uhttp://library.ncl.res.in/content/unusual-monodentate-binding-mode-22-dipyridylamine-l-isomeric-transacac2ru-iil2-trans-103896nas a2200193 4500008004100000245015900041210006900200260000800269300001400277490000700291520315400298100002103452700001203473700002203485700001503507700002603522700002603548856012803574 2006 eng d00a2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz)-derived [Ru-II(tptz)(acac)(CH3CN)](+) and mixed-valent [(acac)(2)Ru-III{(mu-tptz-H+)(-)}Ru-II(acac)(CH3CN)](+)0 a246tris2pyridyl135triazine tptzderived RuIItptzacacCH3CN and mix cMAR a2413-24230 v453 a

Mononuclear [Ru-II(tptz)(acac:)(CH3CN)]ClO4 ((ClO4)-Cl-[1]) and mixed-valent dinuclear [(acac)(2)Ru-III{(mu-tptz-H+)(-)}Ru-II(acac)(CH3CN)]ClO4 ([5]ClO4; acac = acetylacetonate) complexes have been synthesized via the reactions of Ru-II(acac)2(CH3CN)(2) and 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz), in 1:1 and 2:1 molar ratios, respectively. In [1]ClO4, tptz binds with the Ru-II ion in a tridentate N,N,N mode (motif A), whereas in [5]ClO4, tptz: bridges the metal ions unsymmetrically via the tridentate neutral N,N,N mode with the Ru-II center and cyclometalated N,C- state with the Ru-III site (motif F). The activation of the coordinated nitrile function in [1]ClO4 and [5]ClO4 in the presence of ethanol and alkylamine leads to the formation of iminoester ([2]ClO4 and [7]ClO4) and amidine ([4]ClO4) derivatives, respectively. Crystal structure analysis of [2]ClO4 reveals the formation of a beautiful eight-membered water cluster having a chair conformation. The cluster is H-bonded to the pendant pyridyl ring N of tptz and also with the O atom of the perchlorate ion, which, in turn, makes short (C-H––-O) contacts with the neighboring molecule, leading to a H-bonding network. The redox potentials corresponding to the (RuI)-I-I state in both the mononuclear {[(acac)(tptz)Ru-II-N=-C-CH3]ClO4 ([1]ClO4) >> [(acac)(tptz)Ru-II-NH=C(CH3)-OC2H5]ClO4 ([2]ClO4) > [(acac)(tptz)(RuNH2)-N-II-C6H4(CH3)]ClO4 ([3]ClO4) > [(acac)(tptz)Ru-II-NH=C(CH3)-NHC2H5]ClO4 ([4]ClO4)} and dinuclear {[(acac)(2)Ru-III-{mu-tptz-H+)(-)}Ru-II(acac)(N equivalent to C-CH3)]ClO4 {(mu-tptz-H+)(-)}Ru-II(acac)(N equivalent to C-CH3)]ClO4 ([5]ClO4), [(acac)(2)Ru-III[(mu-tptz-H+(N-O ([6]ClO4), [(acac)(2)Ru-III{(mu-tptz-H+)(-)}Ru-II(acac)(NH=C(CH3)-OC2H5)]ClO4( [7]ClO4), and [(acac)(2)Ru-III{(mu-tptz-H+)(-)}Ru-II(acac)(NC4H4N)]ClO4 ([8]ClO4), complexes vary systematically depending on the electronic nature of the coordinated sixth ligands. However, potentials involving the Ru-III center in the dinuclear complexes remain more or less invariant. The mixed-valent (RuRuIII)-Ru-II species ([5]ClO4-[8]ClO4) exhibits high comproportionation constant (K-c) values of 1.1 X 10(12)-2 x 109, with substantial contribution from the donor center asymmetry at the two metal sites. Complexes display Ru-II- and Ru-III-based metal-to-ligand and ligand-to-metal charge-transfer transitions, respectively, in the visible region and ligand-based transitions in the UV region. In spite of reasonably high K, values for [5]ClO4[8]ClO4, the expected intervalence charge-transfer transitions did not resolve in the tpical near-IR region up to 2000 nm. The paramagnetic (RuRuIII)-Ru-II species ([5]ClO4-[8]ClO4) displays rhombic electron paramagnetic resonance (EPR) spectra at 77 K (< g > similar to 2.15 and Delta g similar to 0.5), typical of a low-spin Ru-III ion in a distorted octahedral environment. The one-electron-reduced tptz complexes [RuII(tptz center dot-)(acac)(CH3CN)] (1) and [(acac)(2)Ru-III{mu-tptz-H+)(center dot 2-)}-Ru-II(acac)(CH3CN)] (5), however, show a free-radical-type EPR signal near g = 2.0 with partial metal contribution.

1 aGhumaan, Sandeep1 aKar, S.1 aMobin, Shaikh, M.1 aHarish, B.1 aPuranik, Vedavati, G.1 aLahiri, Goutam, Kumar uhttp://library.ncl.res.in/content/246-tris2-pyridyl-135-triazine-tptz-derived-ru-iitptzacacch3cn-and-mixed-valent-acac2ru-102689nas a2200313 4500008004100000022001400041245011600055210006900171260009500240300001200335490000800347520155000355653003601905653002801941653001101969653003001980653002002010653001802030653000802048100001902056700001702075700001702092700003502109700002702144700003002171700001902201700002602220856012902246 2006 eng d a0021-951700aEffect of spacer groups on the performance of MCM-41-supported platinum cluster-derived hydrogenation catalysts0 aEffect of spacer groups on the performance of MCM41supported pla a525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USAbACADEMIC PRESS INC ELSEVIER SCIENCEcSEP a332-3390 v2423 a

MCM-41 was functionalized with (EtO)(3)SiCH2Cl, (MeO)(3)SiCH2CH2CH2Cl, and (CH3)Cl2SiCH2Cl. The functionalized materials were characterized by solid-state NMR (CPMAS, Si-29 and C-13) and XPS. The NMR data indicate that three new silicon environments were created by(EtO)(3)SiCH2Cl and (MeO)(3)SiCH2CH2CH2Cl, whereas with (CH3)Cl2SiCH2Cl, two new silicon environments were obtained. XPS results from Si 2p core level and the valence band from the material functionalized by (MeO)(3)Si(CH2)(3)Cl was found to be the same as that of the corresponding fresh catalyst (1a), in contrast to that of the materials functionalized by the other two silane reagents. After further functionalization with triethylamine, these materials were used as inorganic anion exchangers to support the cluster anion [Pt-12(CO)(24)](2-). Solid-state NMR (29Si, C-13, N-15) was used to establish the presence of the quaternary ammonium group in the cluster-supported species. Analogous materials were also created using fumed silica as the support, and all of the cluster-supported materials were tested as catalysts for the hydrogenation of methyl pyruvate, acetophenone, nitrobenzene, benzonitrile, ethylacetoacetate, 4-nitrotoluene, cyclohexanone, allyl alcohol, and styrene. The best activity was obtained for the catalyst that had MCM-41 as the support and chloropropyl as the spacer group. TEM showed that the supports and the spacer groups had observable effects on the platinum crystallite size of the catalysts. (c) 2006 Elsevier Inc. All rights reserved.

10afunctionalized inorganic oxides10ahydrogenation catalysts10aMCM-4110aplatinum carbonyl cluster10aSolid-state NMR10aspacer groups10aXPS1 aMaity, Niladri1 aBasu, Susmit1 aMapa, Maitri1 aRajamohanan, Pattuparambil, R.1 aGanapathy, Subramanian1 aGopinath, Chinnakonda, S.1 aBhaduri, Sumit1 aLahiri, Goutam, Kumar uhttp://library.ncl.res.in/content/effect-spacer-groups-performance-mcm-41-supported-platinum-cluster-derived-hydrogenation-102187nas a2200265 4500008004100000022001400041245012200055210006900177260009500246300001200341490000800353520115600361653004001517653002301557653002601580653002801606653003001634100001701664700001701681700003001698700001801728700001901746700002601765856013001791 2006 eng d a0021-951700aMCM-41-supported platinum carbonyl cluster-derived catalysts for asymmetric and nonasymmetric hydrogenation reactions0 aMCM41supported platinum carbonyl clusterderived catalysts for as a525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USAbACADEMIC PRESS INC ELSEVIER SCIENCEcAPR a154-1610 v2393 a

Anionic platinum carbonyl Cluster ([Pt-12(CO)(24)](2-)) was ion-paired with the 3-chloropropyltrimethoxysilyl-ammonium group chemically bound to the surface of MCM-41. The materials undergo quick decarbonylation and have been characterized before decarbonylation by IR and UV-vis spectroscopy and after decarbonylation by XPS and TEM. They have been used as catalysts for the hydrogenations of methyl pyruvate, acetophenone, nitrobenzene, benzonitrile, and ethylacetoacetate. The support and the quaternary ammonium groups have significant effects on surface platinum concentration, crystallite size, and observed activity. In the hydrogenation of the prochiral substrates methyl pyruvate or acetophenone, the cinchonidine-based catalyst gives significant enantioselectivity under optimum conditions. A kinetic model that includes an enantioselective product-formation step and a hydrogen pressure-dependent step for the deactivation of the enantioselective sites gives reasonable agreement between predicted and observed enantioselectivity. The model is also in accordance with the XPS and TEM data. (c) 2006 Elsevier Inc. All rights reserved.

10aasymmetric/non-asymmetric catalysis10aEnantioselectivity10afunctionalized MCM-4110ahydrogenation catalysts10aplatinum carbonyl cluster1 aBasu, Susmit1 aMapa, Maitri1 aGopinath, Chinnakonda, S.1 aDoble, Mukesh1 aBhaduri, Sumit1 aLahiri, Goutam, Kumar uhttp://library.ncl.res.in/content/mcm-41-supported-platinum-carbonyl-cluster-derived-catalysts-asymmetric-and-nonasymmetric-101323nas a2200301 4500008004100000022001400041245018600055210006900241260007800310300001400388490000700402520021200409653002400621653001900645653001400664653001700678653001800695653002900713100001800742700001500760700001400775700001700789700002200806700002600828700001900854700002600873856012200899 2006 eng d a0947-653900aMetal-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 system0 aMetalinduced reductive ring opening of 1245tetrazines Three resu aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcFEB  a1316-13250 v453 a

{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 [

10acrystal engineering10ahydrogen bonds10amolecular10arecocynition10aSelf-assembly10asupramolecular chemistry1 aMaji, Somnath1 aSarkar, B.1 aPatra, S.1 aFiedler, Jan1 aMobin, Shaikh, M.1 aPuranik, Vedavati, G.1 aKaim, Wolfgang1 aLahiri, Goutam, Kumar uhttp://library.ncl.res.in/content/metal-induced-reductive-ring-opening-1245-tetrazines-three-resulting-coordination-101547nas a2200205 4500008004100000022001400041245009600055210006900151260007100220300001400291490000800305520074500313100001901058700003501077700002701112700003001139700001901169700002601188856012701214 2008 eng d a1932-744700aMCM-41-supported organometallic-derived nanopalladium as a selective hydrogenation catalyst0 aMCM41supported organometallicderived nanopalladium as a selectiv a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJUN a9428-94330 v1123 a

Palladium nanocatalysts have been prepared by anchoring (eta(3)-C(3)H(5))(2)Pd(2)Cl(2) onto dian-tine-functionalized MCM-41 supports followed by reaction with hydrogen under catalytic conditions. The catalyst precursor and used catalyst have been studied by solid-state NMR ((13)C, (29)Si), XPS, and TEM. The organometallic-derived catalyst exhibits the best performance (activity and selectivity) to date toward the selective hydrogenation of industrially relevant o- and m-chloronitrobenzene to the corresponding chloroaniline derivatives and is distinctly superior to 5% Pd/C. Grazing angle XPS studies reveal that conversion of the tethered molecular species to the nanoparticles of palladium produces a core-shell nanostructure.

1 aMaity, Niladri1 aRajamohanan, Pattuparambil, R.1 aGanapathy, Subramanian1 aGopinath, Chinnakonda, S.1 aBhaduri, Sumit1 aLahiri, Goutam, Kumar uhttp://library.ncl.res.in/content/mcm-41-supported-organometallic-derived-nanopalladium-selective-hydrogenation-catalyst-001232nas a2200265 4500008004100000022001400041245010500055210006900160260007300229300001200302490000800314520025000322653002500572653002600597653002800623653001700651653003100668100001900699700001700718700002900735700003000764700001900794700002600813856012700839 2008 eng d a0926-860X00aMCM-41-supported ruthenium carbonyl cluster-derived catalysts for asymmetric hydrogenation reactions0 aMCM41supported ruthenium carbonyl clusterderived catalysts for a aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJUL a124-1300 v3443 a

{The anionic ruthenium carbonyl cluster [Ru-4(mu-H)(3)(CO)(12)](-) has been ion-paired with (3-chloropropyl)-trimethoxysilyl-cinchonidium or sparteinium groups chemically bound to the surfaces of MCM-41 [(MCM-41-)(-O)(3)SiCH2CH2CH2NR3+Cl-

10aasymmetric catalysis10afunctionalized MCM-4110ahydrogenation catalysts10ananocatalyst10aruthenium carbonyl cluster1 aIndra, Arindam1 aBasu, Susmit1 aKulkarni, Dhanashree, G.1 aGopinath, Chinnakonda, S.1 aBhaduri, Sumit1 aLahiri, Goutam, Kumar uhttp://library.ncl.res.in/content/mcm-41-supported-ruthenium-carbonyl-cluster-derived-catalysts-asymmetric-hydrogenation-003126nas a2200313 4500008004100000022001400041245016800055210006900223260007600292300001600368490000700384520196100391653002402352653001302376653001402389653002802403653002602431653003202457100002102489700002102510700001802531700002602549700001702575700002702592700002802619700001902647700002602666856012002692 2008 eng d a0947-653900aValence-state analysis through spectroelectrochemistry in a series of quinonoid-bridged diruthenium complexes [(acac)(2)Ru(mu-L)Ru(acac)(2)](n) (n =+2,+1, 0,-1,-2)0 aValencestate analysis through spectroelectrochemistry in a serie aCOMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USAbWILEY-BLACKWELLcOCT a10816-108280 v143 a

The quinonoid ligand-bridged diruthenium compounds [(acac)(2)Ru(mu-L2-)Ru(acac)(2)] (acac(-) = acetylacetonato = 2,4-pentanedionato; L2- = 2,5-dioxido-1,4-benzoquinone, 1; 3,6-dichloro-2,5-dioxido-1,4-benzoquinone, 2; 5,8-dioxido-1,4-naphthoquinone, 3; 2-3-dichloro-5,8-dioxido-1,4-naphthoquinone, 4; 1,5-dioxido-9,10-anthraquinone, 5; and 1,5-diimido-9,10-anthraquinone, 6) were prepared and characterized analytically. The crystal structure analysis of 5 in the rac configuration reveals two tris(2,4-pentanedionato)ruthenium moieties with an extended anthracenedione-derived bis(ketoenolatee) pi-conjugated bridging ligand. The weakly antiferro-magnetically coupled {Ru-III(mu-L2-)Ru–(III)} configuration in 1-6 exhibits complicated overall magnetic and EPR responses,. ne simultaneous presence of highly redox-active quinonoid-bridging ligands and of two ruthenium centers capable of adopting the oxidation states +2, +3, and +4 creates a large variety of possible oxidation state combinations. Accordingly. the complexes 1-6 exhibit two reversible one-electron oxidation steps and at least two reversible reduction processes. Shifts to positive potentials were observed on introduction of Cl substituents (1 -> 2, 3 -> 4) or through replacement of NH by O (6 -> 5). The ligand-to-metal charge transfer (LMCT) absorptions in the visible region of the neutral molecules become more intense and shifted to lower energies on stepwise reduction with two electrons. On oxidation, the para-substituted systems 1-4 exhibit monocation intermediates with intervalence charge transfer (IVCT) transitions of (RuRuIV)-Ru-III mixed-valent species. In contrast, the differently substituted systems 5 and 6 show no such near infrared (NIR) absorption. While the first reduction steps are thus assigned to largely ligand-centered processes, the oxidation appears to involve metal-ligand delocalized molecular orbitals with variable degrees of mixing.

10amagnetic properties10aquinones10aruthenium10aspectroelectrochemistry10astructure elucidation10avalence-state distributions1 aGhumaan, Sandeep1 aSarkar, Biprajit1 aMaji, Somnath1 aPuranik, Vedavati, G.1 aFiedler, Jan1 aUrbanos, Francisco, A.1 aJimenez-Aparicio, Reyes1 aKaim, Wolfgang1 aLahiri, Goutam, Kumar uhttp://library.ncl.res.in/content/valence-state-analysis-through-spectroelectrochemistry-series-quinonoid-bridged-002264nas a2200181 4500008004100000022001400041245010000055210006900155260011000224300001200334490000700346520151600353100002101869700003001890700001901920700002601939856011701965 2009 eng d a1463-926200aApplications of a high performance platinum nanocatalyst for the oxidation of alcohols in water0 aApplications of a high performance platinum nanocatalyst for the aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcFEB a554-5610 v113 a

Nanoparticles of platinum (NP-Pt), have been synthesized by supporting high nuclearity anionic carbonyl cluster (Chini cluster) on a water soluble anion exchanger, and the performance of this material, 1, as an oxidation catalyst for alcohols in water has been studied. The E-factor for the synthesis of NP-Pt by this method has been calculated and compared with that of other NP-Pt recently reported in the literature. With 1 as a catalyst, oxidations of a variety of primary and secondary alcohols by dioxygen are achieved and high turnover numbers and selectivities are obtained. The performances of 1 in the oxidation of benzyl alcohol and 1-phenylethanol are compared with those of three other platinum catalysts. These are platinum nanoparticles 2 prepared by the hydrogen reduction of [PtCl6](2-) supported on the same water soluble polymer, 5% Pt on carbon, and 5% Pt on alumina, designated as 3 and 4, respectively. 1 has been found to be considerably more active than 2- 4 and also other reported water soluble platinum nanocatalysts. After many turnovers (similar to 1000 and similar to 165 for benzyl alcohol and 1-phenyl ethanol, respectively) partial deactivation (similar to 40%) is observed, but the deactivated catalyst can be fully regenerated by treatment with dihydrogen. The TEM data of fresh, deactivated and regenerated 1 show a correlation between the particle size and activity. A mechanism consistent with this and other experimental observations including XPS data is proposed.

1 aMaity, Prasenjit1 aGopinath, Chinnakonda, S.1 aBhaduri, Sumit1 aLahiri, Goutam, Kumar uhttp://library.ncl.res.in/content/applications-high-performance-platinum-nanocatalyst-oxidation-alcohols-water-001984nas a2200253 4500008004100000022001400041245011600055210006900171260007300240300001200313490000800325520103000333653002401363653002401387653002701411653001101438653002801449100001901477700003501496700003001531700001901561700002601580856012401606 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 uhttp://library.ncl.res.in/content/selective-hydrogenation-chloronitrobenzenes-mcm-41-supported-platinum-allyl-complex-002319nas a2200205 4500008004100000245013500041210006900176260000800245300001400253490000700267520154800274100001801822700003101840700001801871700002201889700002601911700001901937700002601956856013101982 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 uhttp://library.ncl.res.in/content/selective-recognition-fluoride-and-acetate-newly-designed-ruthenium-framework-experimental-003343nas a2200241 4500008004100000022001400041245016200055210006900217260011000286300001600396490000700412520235500419100001802774700002402792700002102816700002502837700001702862700002202879700002602901700001902927700002602946856012902972 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 uhttp://library.ncl.res.in/content/strong-metal-metal-coupling-mixed-valent-intermediates-cllrumu-tppzrulcl-l-beta-diketonato02133nas a2200181 4500008004100000022001400041245011000055210006900165260011000234300001400344490000600358520136900364100001901733700003001752700001901782700002601801856012401827 2013 eng d a2044-475300aHydroxyapatite supported palladium catalysts for suzuki-miyaura cross-coupling reaction in aqueous medium0 aHydroxyapatite supported palladium catalysts for suzukimiyaura c aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcMAR a1625-16330 v33 a

Supported palladium catalyst 1 has been prepared by the immobilisation of [Pd(COD)Cl-2] (COD = 1,5-cyclooctadiene) on hydroxyapatite. Catalyst 2 has been prepared by subsequent reduction of catalyst 1 with sodium borohydride in ethanol. Under similar reaction conditions, catalyst 1 with Pd2+, is found to be almost five times more active than 2. Using 1 as the catalyst and water as the solvent, reaction conditions for Suzuki-Miyaura cross-coupling reactions have been optimised under aerobic conditions. The best catalytic activities are observed in the presence of potassium carbonate as the base and tetrabutylammonium bromide as a promoter. Catalyst 1 has been tested for catalytic cross-coupling reactions with sixteen different, electronically neutral, electron rich, electron poor and sterically hindered aryl boronic acids, and several different aryl halides including aryl chlorides. More than thousand turnovers and high selectivities to the hetero-coupled products have been observed in most cases. For many substrates the turnovers with 1 are notably more than what has been reported with other supported catalysts in water. The recyclability and scale-up potential of catalyst 1 have been tested and found to be satisfactory. A negligible drop in activity is observed over ten recycles with an accumulated turnover number of similar to 30000.

1 aIndra, Arindam1 aGopinath, Chinnakonda, S.1 aBhaduri, Sumit1 aLahiri, Goutam, Kumar uhttp://library.ncl.res.in/content/hydroxyapatite-supported-palladium-catalysts-suzuki-miyaura-cross-coupling-reaction-0