Download or read book The Reactivity of Mononuclear Molybdenum and Rhenium Alkyne Complexes written by S. J. Rumble and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aspects of the Reactivity of Mononuclear Molybdenum Complexes Containing an Alkyne Ligand written by Christopher M. Woolhouse and published by . This book was released on 1989 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aspects of the Reactivity of Mononuclear Molybdenum Complexes Containing an Alkyne Ligand written by C. Woolhouse and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Reactivity of Molybdenum and Rhenium Site differentiated Hexanuclear Cluster Complexes written by Meghan K. Cochran and published by . This book was released on 2004 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Synthesis and Reactions of Molybdenum II and Tungsten II Alkyne Complexes written by Elaine M. Armstrong and published by . This book was released on 1989 with total page 710 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Redox Reactivity of Mononuclear and Binuclear Rhenium Complexes written by Grant Newton Holder and published by . This book was released on 1988 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reactions of fulvalene molybdenumruthenium pentacarbonyl with Alkynes written by Mark Alan Huffman and published by . This book was released on 1989 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reactivity and Properties of Alkyne Ligands in Molybdenum and Tungsten Alkyne Dithiocarbamate Complexes written by Janet R. Morrow and published by . This book was released on 1985 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Chemistry and Redox Properties of Molybdenum and Rhenium Complexes with Sulphur Donor Ligands written by B. D. Neaves and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aspects of C H Activation in Metal Complexes Containing Sulfur Ligands written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The research project proposed to synthesize new metal complexes with sulfido, disulfido and other types of reactive sulfur ligands, and to explore the joint reactivity of metal and sulfur ligands with hydrogen and organic molecules. The overall objective was to investigate reaction pathways relevant to those observed for the heterogeneous metal sulfide catalysts which promote hydrogen activation, hydrogenation-dehydrogenation of organic substrates, and hydrogenolysis of carbon-heteroatom bonds. Particular emphasis was placed on CpRe derivatives (where Cp might be C5H5 or alkylated versions) so that comparisons could be made with the previously studied CpMo complexes, which showed extensive reactivity at the sulfur ligands. Heterogeneous rhenium sulfides generally show higher catalytic activity than molybdenum sulfides, and this is attributed, in part, to the weaker Re-S bond strength, relative to the moybdenum-sulfur bond. In our studies of discrete Re-sulfide complexes, we have also observed evidence for weaker Re-S bonds relative to the molybdenum systems. In addition we have characterized novel hydrogen activation by rhenium sulfido complexes, as well as carbon-hydrogen, carbon-sulfur and metal sulfur bond cleavage reactions. Hydrogen Activation. The complex Cpà ̄Â?Â[1/2]ReCl2S3 was synthesized in ca 70% yield and characterized by an X-ray diffraction study which confirms that the complex contains a h2-trisulfide ligand. The cyclic voltammogram of Cpà ̄Â?Â[1/2]ReCl2S3 shows a wide window of redox stability with an irreversible reduction wave at à ̄Â?Â[1/2]0.97 V and an irreversible oxidation at +1.03 V vs Fc. Nevertheless, the complex undergoes a facile reaction with hydrogen at 50oC to form H2S and a new dinuclear sulfido bridged rhenium complex. This reaction is of interest because it is the first example of the hydrogenolysis of a discrete metal polysulfide complex to produce H2S, a reaction also observed for heterogeneous rhenium sulfides. The reaction contrasts with those of related Cp-molybdenum complexes with sulfide ligands, which also activate hydrogen, but generally form hydrosulfido products without H2S elimination. C-H and C-S Cleavage Reactions. New mononuclear Cp'Re(dithiolate) complexes such as Cpà ̄Â?Â[1/2]ReCl2(SC2H4S), 1, have been prepared and characterized and have been found to display a very interesting range of reactions. The thermal reaction of 1 involves the dehydrogenation of the alkanedithiolate ligand to form Cp'ReCl2(SCH=CHS), 2 as well as a competing elimination of olefin from the dithiolate ligand in 1. On the basic of kinetic and related studies, the mechanism is proposed to involve a sequential series of reactions. In the first reaction, the olefin extrusion is proposed to produce a reactive Re-disulfide or Re-bis(sulfido) intermediate, CpReCl2S2 which serves as an oxidant for the dithiolate complex 1. The ability of the bis sulfido complex to dehydrogenate hydrocarbons is a unique feature and several additional dehydrogenation reactions with this system have been characterized, including the oxidation of other dithiolate complexes, of tetrahydro-naphthalene and of cyclohexadiene. Precedents for the role of metal sulfides in dehydrogenation reactions have been reported for heterogeneous metal sulfide surfaces. This work has begun to provide information about the electronic and structural features necessary for such reactivity. Carbon Sulfur Bond Formation. When the thermal reaction of 1 was carried out in the presence of excess dry ethene a new reaction was observed in which the dithiolate ligand is displaced by incoming olefin to form the cyclic organic product, 1,4-dithiane. The Re product is identified as Cpà ̄Â?Â[1/2]Re(alkene)Cl2 on the basis of NMR and mass spectroscopic data. Similar reactions with alkynes have been found to form unsaturated 6-membered rings and reactions with 1,3 dithiolate complexes form the organic 7-membered rings. To our knowledge the formation of cyclic bis-thioethers by the reactions of an alkene or alkyne with a discrete dithiolate metal complex has not been reported previously. Conclusions. A series of new rhenium complexes with sulfido, disulfido, and thiolate ligands have been synthesized and characterized. The complexes have shown novel patterns of reactivity at the sulfur ligands that include hydrogen activation and addition, dehydrogenations, and carbon -sulfur bond formation. Systematic studies of sulfur ligand reactivity as the coligands in these rhenium complexes were varied have established electronic features that favor the novel ligand based reactivity. This series of complexes provides a model system for aspects of rhenium-sulfide surface reactivity, and have led to the suggestion of new mechanistic possibilities.

Download or read book Aspects of C H Activation in Metal Complexes Containing Sulfur Ligands written by Mary C. Rakowski-DuBois and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The research project proposed to synthesize new metal complexes with sulfido, disulfido and other types of reactive sulfur ligands, and to explore the joint reactivity of metal and sulfur ligands with hydrogen and organic molecules. The overall objective was to investigate reaction pathways relevant to those observed for the heterogeneous metal sulfide catalysts which promote hydrogen activation, hydrogenation-dehydrogenation of organic substrates, and hydrogenolysis of carbon-heteroatom bonds. Particular emphasis was placed on CpRe derivatives (where Cp might be C5H5 or alkylated versions) so that comparisons could be made with the previously studied CpMo complexes, which showed extensive reactivity at the sulfur ligands. Heterogeneous rhenium sulfides generally show higher catalytic activity than molybdenum sulfides, and this is attributed, in part, to the weaker Re-S bond strength, relative to the moybdenum-sulfur bond. In our studies of discrete Re-sulfide complexes, we have also observed evidence for weaker Re-S bonds relative to the molybdenum systems. In addition we have characterized novel hydrogen activation by rhenium sulfido complexes, as well as carbon-hydrogen, carbon-sulfur and metal sulfur bond cleavage reactions. Hydrogen Activation. The complex Cp{prime}ReCl2S3 was synthesized in ca 70% yield and characterized by an X-ray diffraction study which confirms that the complex contains a {eta}2-trisulfide ligand. The cyclic voltammogram of Cp{prime}ReCl2S3 shows a wide window of redox stability with an irreversible reduction wave at -0.97 V and an irreversible oxidation at +1.03 V vs Fc. Nevertheless, the complex undergoes a facile reaction with hydrogen at 50 C to form H2S and a new dinuclear sulfido bridged rhenium complex. This reaction is of interest because it is the first example of the hydrogenolysis of a discrete metal polysulfide complex to produce H2S, a reaction also observed for heterogeneous rhenium sulfides. The reaction contrasts with those of related Cp-molybdenum complexes with sulfide ligands, which also activate hydrogen, but generally form hydrosulfido products without H2S elimination. C-H and C-S Cleavage Reactions. New mononuclear Cp{prime}Re(dithiolate) complexes such as Cp{prime}ReCl2(SC2H4S), 1, have been prepared and characterized and have been found to display a very interesting range of reactions. The thermal reaction of 1 involves the dehydrogenation of the alkanedithiolate ligand to form Cp{prime}ReCl2(SCH=CHS), 2 as well as a competing elimination of olefin from the dithiolate ligand in 1. On the basic of kinetic and related studies, the mechanism is proposed to involve a sequential series of reactions. In the first reaction, the olefin extrusion is proposed to produce a reactive Re-disulfide or Re-bis(sulfido) intermediate, CpReCl2S2 which serves as an oxidant for the dithiolate complex 1. The ability of the bis sulfido complex to dehydrogenate hydrocarbons is a unique feature and several additional dehydrogenation reactions with this system have been characterized, including the oxidation of other dithiolate complexes, of tetrahydro-naphthalene and of cyclohexadiene. Precedents for the role of metal sulfides in dehydrogenation reactions have been reported for heterogeneous metal sulfide surfaces. This work has begun to provide information about the electronic and structural features necessary for such reactivity. Carbon Sulfur Bond Formation. When the thermal reaction of 1 was carried out in the presence of excess dry ethene a new reaction was observed in which the dithiolate ligand is displaced by incoming olefin to form the cyclic organic product, 1,4-dithiane. The Re product is identified as Cp{prime}Re(alkene)Cl2 on the basis of NMR and mass spectroscopic data. Similar reactions with alkynes have been found to form unsaturated 6-membered rings and reactions with 1,3 dithiolate complexes form the organic 7-membered rings. To our knowledge the formation of cyclic bis-thioethers by the reactions of an alkene or alkyne with a discrete dithiolate metal complex has not been reported previously. Conclusions. A series of new rhenium complexes with sulfido, disulfido, and thiolate ligands have been synthesized and characterized. The complexes have shown novel patterns of reactivity at the sulfur ligands that include hydrogen activation and addition, dehydrogenations, and carbon-sulfur bond formation. Systematic studies of sulfur ligand reactivity as the coligands in these rhenium complexes were varied have established electronic features that favor the novel ligand based reactivity. This series of complexes provides a model system for aspects of rhenium-sulfide surface reactivity, and have led to the suggestion of new mechanistic possibilities.

Download or read book British Reports Translations and Theses written by British Library. Document Supply Centre and published by . This book was released on 1995 with total page 772 pages. Available in PDF, EPUB and Kindle. Book excerpt: Issue for Mar. 1981 contains index for Jan.-Mar. 1981 in microfiche form.

Download or read book The Redox Chemistry of Molybdenum and Tungsten Alkyne Complexes written by Elena Patrkon-Rodrkiguez and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Reactivity of Molybdenum and Tungsten Alkylidyne Complexes written by Laughlin G. McCullough and published by . This book was released on 1984 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Organometallic Chemistry written by and published by Academic Press. This book was released on 1983-12-01 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Organometallic Chemistry

Download or read book Index to Theses with Abstracts Accepted for Higher Degrees by the Universities of Great Britain and Ireland and the Council for National Academic Awards written by and published by . This book was released on 1998 with total page 922 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theses on any subject submitted by the academic libraries in the UK and Ireland.

Download or read book Comprehensive Organometallic Chemistry III Volume 5 written by D. M. P. Mingos and published by . This book was released on 2007 with total page 1008 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides essential information for any chemist or technologist who needs to use or apply organometallic compounds. Provides a comprehensive overview of recent developments in the field and attempts to predict trends in the field over the next ten years.