03186nas a2200229 4500008004100000022001400041245025900055210006900314260007100383300001400454490000700468520220000475100001502675700001302690700001202703700002202715700001902737700002602756700001602782700002602798856013202824 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 uhttps://library.ncl.res.in/content/effect-2-2-pyridylazole-based-ancillary-ligands-l1-4-electrophilicity-nitrosyl-function-ru-101606nas a2200217 4500008004100000022001400041245025900055210006900314260007100383300001200454490000700466520065000473100001501123700001801138700002201156700001801178700001601196700001901212700002601231856013101257 2005 eng d a0276-733300aSynthesis and characterization of ferrocenylchalcogenopropargyl complexes [Fe(eta(5)-(C5H4ECH2C)-C-I CH)(2)] (E-I = Se, S) and their reactions to form unusual ferrocenyl-containing metal clusters with eclipsed Cp rings and new five-membered (FeECH)-C-I =0 aSynthesis and characterization of ferrocenylchalcogenopropargyl  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJAN a367-3720 v243 a

{The new bis(chalcogenopropargyl)ferrocene complexes [Fe(eta(5)-C(5)H(4)E(I)CH(2)CdropCH)(2)] (E-I = Se, 1; E-I = S, 2) have been prepared by treatment of the dilithiated [Fe(eta(5)-C5H4Li)(2)] with Se or S powder, followed by reaction with propargyl bromide. Reaction of 1 and 2 with [Fe2M(mu(3)-E)(2)(CO)(9)] (E = S, Se and M = Fe, Ru) forms new clusters which feature an unusual five-membered (FeECH)-C-I=CCH2 ring with a pi bond between the olefinic unit and the Fe atom, and the Cp rings adopt an eclipsed arrangement. The structures of 1 and [Fe(eta(5)-C5H4E(I)-CH(2)CdropCH) (eta(5)-C5H4{Fe2M(CO)(8)(mu-E)((ECHCCH2)-C-I)})] (M = Fe

1 aMathur, P.1 aSingh, V., K.1 aMobin, Shaikh, M.1 aSrinivasu, C.1 aTrivedi, R.1 aBhunia, A., K.1 aPuranik, Vedavati, G. uhttps://library.ncl.res.in/content/synthesis-and-characterization-ferrocenylchalcogenopropargyl-complexes-feeta5-c5h4ech2c-c-101995nas a2200229 4500008004100000022001400041245026000055210006900315260007100384300001400455490000700469520099600476100001201472700001501484700002201499700002001521700001701541700002601558700002801584700002601612856012701638 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 uhttps://library.ncl.res.in/content/unusual-monodentate-binding-mode-22-dipyridylamine-l-isomeric-transacac2ru-iil2-trans-103897nas a2200193 4500008004100000245015900041210006900200260000800269300001400277490000700291520315400298100002103452700001203473700002203485700001503507700002603522700002603548856012903574 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 uhttps://library.ncl.res.in/content/246-tris2-pyridyl-135-triazine-tptz-derived-ru-iitptzacacch3cn-and-mixed-valent-acac2ru-101324nas a2200301 4500008004100000022001400041245018600055210006900241260007800310300001400388490000700402520021200409653002400621653001900645653001400664653001700678653001800695653002900713100001800742700001500760700001400775700001700789700002200806700002600828700001900854700002600873856012300899 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 uhttps://library.ncl.res.in/content/metal-induced-reductive-ring-opening-1245-tetrazines-three-resulting-coordination-101300nas a2200169 4500008004100000245008800041210006900129260000800198300001400206490000700220520069600227100002000923700002000943700002200963700003100985856011401016 2009 eng d00aCopper (I) complexes of a thioether-functionalized short-bite aminobis(phosphonite)0 aCopper I complexes of a thioetherfunctionalized shortbite aminob cNOV a101–1060 v283 a

Copper(I) complexes of short-bite aminobis(phosphonite), PhN{P(–OC10H6(μ-S)C10H6O–)}2 (1) have been synthesized. Reactions of 1 with an excess of CuX (X = Cl, Br, and I) afforded the ligand-bridged binuclear complexes, [PhN(PR-κP)2{Cu(μ-X)(MeCN)}2] (2, X = Cl; 3, X = Br; 4, X = I; R = –OC10H6(μ-S)C10H6O–), whereas treatment with 0.5 equiv. of [Cu(MeCN)4]PF6 produces the mononuclear bischelated cationic complex, [{PhN(PR-κP)2}2Cu](PF6) (5). Single crystal X-ray structures of complexes 3 and 4 are reported. Complex 3 shows strong π–π stacking interactions between the naphthyl moieties, whereas complex 4 shows ligand-supported Cu⋯Cu metallophilic interactions.

1 aPunji, Benudhar1 aMague, Joel, T.1 aMobin, Shaikh, M.1 aBalakrishna, Maravanji, S. uhttps://library.ncl.res.in/content/copper-i-complexes-thioether-functionalized-short-bite-aminobisphosphonite02320nas 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