- Immobilized Cobalt Bis(benzenedithiolate) Complexes: Exceptionally Active Heterogeneous Electrocatalysts for Dihydrogen Production from Mildly Acidic Aqueous Solutions
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A series of cobalt bis(benzenedithiolate) complexes with varying benzenedithiolate (general abbreviation: bdt2-) ring substitutions (S2C6X42-) were prepared and adsorbed on inexpensive electrodes composed of (a) reduced graphene oxide (RGO) electrodeposited on fluorine-doped tin oxide (FTO) and (b) highly ordered pyrolytic graphite (HOPG). The catalyst-adsorbed electrodes are characterized by X-ray photoelectron spectroscopy. Catalyst loading across the ligand series improved notably with increasing halide substitution [from 2.7 × 10-11 mol cm-2 for TBA[Co(S2C6H4)2] (1) to 6.22 × 10-10 mol cm-2 for TBA[Co(S2C6Cl4)2] (3)] and increasing ring size of the benzenedithiolate ligand [up to 3.10 × 10-9 mol cm-2 for TBA[Co(S2C10H6)2] (6)]. Electrocatalytic analysis of the complexes immobilized on HOPG elicits a reductive current response indicative of dihydrogen generation in the presence of mildly acidic aqueous solutions (pH 2-4) of trifluoroacetic acid, with overpotentials of around 0.5 V versus SHE (measured vs platinum). Rate constant (kobs) estimates resulting from cyclic voltammetry analysis range from 24 to 230 s-1 with the maximum kobs for TBA[Co(S2C6H2Cl2)2] (2) at an overpotential of 0.59 V versus platinum. Controlled-potential electrolysis studies performed in 0.5 M H2SO4 at -0.5 V versus SHE show impressive initial rate constants of over 500 s-1 under bulk electrolysis conditions; however, steady catalyst deactivation over an 8 h period is observed, with turnover numbers reaching 9.1 × 106. Electrolysis studies reveal that halide substitution is a central factor in improving the turnover stability, whereas the ring size is less of a factor in optimizing the long-term stability of the heterogeneous catalyst manifolds. Catalyst deactivation is likely caused by catalyst desorption from the electrode surfaces.
- Eady, Shawn C.,MacInnes, Molly M.,Lehnert, Nicolai
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- Proton Relay Effects in Pyridyl-Appended Hydrogenase Mimics for Proton Reduction Catalysis
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Hydrogenase enzymes are fast proton reduction catalysts, and their synthetic mimics have been widely studied in the context of solar fuel applications. The mimics are still not nearly as effective as the enzyme, as they lack crucial structural elements, i
- Zaffaroni, Riccardo,Dzik, Wojciech I.,Detz, Remko J.,van der Vlugt, Jarl Ivar,Reek, Joost N. H.
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supporting information
p. 2498 - 2509
(2019/05/28)
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- RUTHENIUM COMPLEXES USEFUL FOR CATALYZING METATHESIS REACTIONS
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Compound of formula (4) or formula (5), wherein L is a neutral ligand, preferably a nitrogen-containing heterocyclic carbene (NHC) such as carbene containing at least two nitrogen atoms, a cyclic aminoalkyl carbene (CAAC) or a bicyclic aminoalkyl carbene (BICAAC); R1, R3, R4, R5, R6, R7, R8, R9, R10 and R11 are, independently, H, unbranched or branched C1-20 alkyl, C5-9 cycloalkyl, unbranched or branched C1-20 alkoxy, optionally bearing one or more halogen atoms, respectively; or aryl, optionally substituted with one or more of unbranched or branched C1-20 alkyl, C5-9 cycloalkyl, unbranched or branched C1-20 alkoxy, aryl, aryloxy, unbranched or branched C1-20 alkylcarbonyl, arylcarbonyl, unbranched or branched C1-20 alkoxycarbonyl, aryloxycarbonyl, heteroaryl, carboxyl, cyano, nitro, amido, aminosulfonyl, N-heteroarylsulfonyl, unbranched or branched C1-20 alkylsulfonyl, arylsulfonyl, unbranched or branched C1-20 alkylsulfinyl, arylsulfinyl, unbranched or branched C1-20 alkylthio, arylthio, sulfonamide, halogen or N(Ry)(Rz), wherein Ry and Rz are independently selected from H and C1-20 alkyl: R2 is H, unbranched or branched C1-20 alkyl.
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Paragraph 0086
(2018/05/27)
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- CATALYSTS FOR EFFICIENT Z-SELECTIVE METATHESIS
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The present application provides, among other things, compounds and methods for metathesis reactions. In some embodiments, provided compounds promote highly efficient and highly Z-selective metathesis. In some embodiments, provided compounds and methods are particularly useful for producing allyl alcohols. In some embodiments, provided compounds have the structure of formula I. In some embodiments, provided compounds comprise ruthenium, and a ligand bonded to ruthenium through a sulfur atom.
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Page/Page column
(2015/01/06)
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- CATALYSTS FOR EFFICIENT Z-SELECTIVE METATHESIS
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The present application provides, among other things, compounds and methods for metathesis reactions. In some embodiments, provided compounds promote highly efficient and highly Z-selective metathesis. In some embodiments, provided compounds and methods are particularly useful for producing allyl alcohols. In some embodiments, provided compounds have the structure of formula I. In some embodiments, provided compounds comprise ruthenium, and a ligand bonded to ruthenium through a sulfur atom.
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Paragraph 00608-00609
(2015/01/09)
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- Organo-metal compositions, preparation and use
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Complexes of a transition metal and a tetrasubstituted aromatic compound which contain at least two transition metal atoms. At least two of the substituents are -SH groups, the other two substituents being -SH, -OH and -NHR. The complexes are prepared by reacting the tetrasubstituted aromatic compound with a transition metal compound in the presence of a disubstituted aromatic compound. Depending on the relative proportions of the di- and tetra--substituted compounds, the resulting complex may contain more than one residue from the tetra-substituted compound and more than two transition metal atoms. The complexes possess infra-red absorbing properties which vary in dependence on the particular complex, the complexes with more than one residue from the tetrasubstituted compound absorbing radiation of longer wavelength. The compounds can be used to provide infra-red absorbing compositions, for example as a coating or inter-layer for glass. The complexes may be used together with one or more different infra-red absorbing materials. The tetra-substituted aromatic compound may be a tetra-thiol and this can be prepared from an aromatic compound containing at least four halogen substituents by reaction with an alkaline thiol compound in the presence of iron and sulphur in a polar solvent such as dimethyl formamide.
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- ZUR DARSTELLUNG VON BENZODITHIET-DERIVATEN DURCH THERMOLYSE 1,2-DITHIO-SUBSTITUIERTER BENZOLE
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The thermal fragmentation of various 1,2-dithio-benzene derivatives R4C6S2(X) with R = H, CH3, F in order to split off favorable leaving molecules X = Cl, CO or H2C=CH2 and to generate the corresponding benzene-1,2-dithiete products (R4C6S2) is investigat
- Bock, H.,Rittmeyer, P.
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p. 291 - 308
(2007/10/02)
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