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Hydride Cluster (hydride + cluster)
Selected AbstractsReduction of Transition-Metal-Coordinated Carbon Monoxide by a Rare-Earth Hydride Cluster: Isolation of Well-Defined Heteromultimetallic Oxycarbene, Oxymethyl, Carbene, and Methyl Complexes,ANGEWANDTE CHEMIE, Issue 42 2009Yasumasa Takenaka Dr. Der vierkernige Yttrium-Polyhydrid-Komplex 1 reduziert koordiniertes CO in Übergangsmetallkomplexen unter Bildung neuartiger Oxycarben-, Oxymethyl-, Carbenoxo- und Methyloxo-Heterometallkomplexe (siehe Schema). Das Reaktionsmuster hängt von der Art der Übergangsmetallcarbonylkomplexe ab. [source] Oxidation of alkanes and alcohols with hydrogen peroxide catalyzed by complex Os3(CO)10(µ-H)2,APPLIED ORGANOMETALLIC CHEMISTRY, Issue 6 2010Georgiy B. Shul'pin Abstract Trinuclear carbonyl hydride cluster, Os3(CO)10(µ-H)2, catalyzes oxidation of cyclooctane to cyclooctyl hydroperoxide by hydrogen peroxide in acetonitrile solution. The hydroperoxide partly decomposes in the course of the reaction to afford cyclooctanone and cyclooctanol. Selectivity parameters obtained in oxidations of various linear and branched alkanes as well as kinetic features of the reaction indicated that the alkane oxidation occurs with the participation of hydroxyl radicals. A similar mechanism operates in transformation of benzene into phenol and styrene into benzaldehyde. The system also oxidizes 1-phenylethanol to acetophenone. The kinetic study led to a conclusion that oxidation of alcohols does not involve hydroxyl radicals as main oxidizing species and apparently proceeds with the participation of osmyl species, ,OsO'. Copyright © 2010 John Wiley & Sons, Ltd. [source] The Role of Solvent on the Mechanism of Proton Transfer to Hydride Complexes: The Case of the [W3PdS4H3(dmpe)3(CO)]+ Cubane ClusterCHEMISTRY - A EUROPEAN JOURNAL, Issue 5 2010Andrés Abstract The kinetics of reaction of the [W3PdS4H3(dmpe)3(CO)]+ hydride cluster (1+) with HCl has been measured in dichloromethane, and a second-order dependence with respect to the acid is found for the initial step. In the presence of added BF4, the second-order dependence is maintained, but there is a deceleration that becomes more evident as the acid concentration increases. DFT calculations indicate that these results can be rationalized on the basis of the mechanism previously proposed for the same reaction of the closely related [W3S4H3(dmpe)3]+ cluster, which involves parallel first- and second-order pathways in which the coordinated hydride interacts with one and two acid molecules, and ion pairing to BF4, hinders formation of dihydrogen bonded adducts able to evolve to the products of proton transfer. Additional DFT calculations are reported to understand the behavior of the cluster in neat acetonitrile and acetonitrile,water mixtures. The interaction of the HCl molecule with CH3CN is stronger than the WH,,,HCl dihydrogen bond and so the reaction pathways operating in dichloromethane become inefficient, in agreement with the lack of reaction between 1+ and HCl in neat acetonitrile. However, the attacking species in acetonitrile,water mixtures is the solvated proton, and DFT calculations indicate that the reaction can then go through pathways involving solvent attack to the W centers, while still maintaining the coordinated hydride, which is made possible by the capability of the cluster to undergo structural changes in its core. [source] Synthesis and Reactions of Polynuclear Polyhydrido Rare Earth Metal Complexes Containing "(C5Me4SiMe3)LnH2" Units: A New Frontier in Rare Earth Metal Hydride ChemistryEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 18 2007Zhaomin Hou Abstract A series of tetranuclear octahydrido rare earth metal complexes of general formula [(C5Me4SiMe3)Ln(,-H)2]4(THF)n (Ln = Sc, Y, Gd, Dy, Ho, Er, Tm, Lu; n = 0, 1, or 2) that contain C5Me4SiMe3 as an ancillary ligand have been prepared and structurally characterized. These hydride clusters are soluble in common organic solvents such as THF, toluene, and hexane, and maintain their tetranuclear framework in solution. Such polynuclear polyhydrido complexes exhibit extremely high and unique reactivity toward a variety of unsaturated substrates including CO, CO2, and nitriles. The reaction of these neutral polyhydrides with one equivalent of [Ph3C][B(C6F5)4] affords the corresponding cationic hydride clusters [(C5Me4SiMe3)4Ln4H7(THF)n][B(C6F5)4], which can act as catalysts for the syndiospecific polymerization of styrene and regio- and stereospecific cis -1,4-polymerization of 1,3-cyclohexadiene. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] | ||||||||||