Download or read book Mechanistic Studies of Reactions of Cationic Dinuclear Molybdenum Sulfide Complexes with Hydrogen written by Linda Lee Lopez and published by . This book was released on 1991 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies of Hydrogen hydrogen and Carbon sulfur Bond Cleavage Lewis Acid Modified Molybdenum Sulfide Complexes and Syntheses and Reactions of Pyrrole Complexes Final Report written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The reactions of hydrogen with dinuclear cyclopentadienyl molybdenum complexes containing bridging sulfido ligands have been identified, and detailed kinetic and mechanistic studies have been carried out on selected systems. The work has led to a detailed proposal for the mechanism of heterolytic hydrogen activation by these homogeneous dinuclear complexes. The hydrogen activation reactions have been further applied in reactions with heterocycles and other small molecules, and pathways for the cleavage of carbon-nitrogen, carbon-sulfur, and carbon-oxygen bonds have been determined. The studies have established well characterized pathways for these transformations which involve reactions at the sulfido ligands of the complexes. These systems provide potential models for important hydrotreating reactions which occur on heterogeneous metal sulfide catalysts. In a related project fundamental factors which might promote the activation of nitrogen heterocycles in the hydrotreating process have been explored. New transition metal complexes containing pyrrole and indole have been synthesized, and the coordination modes of the cyclic ligands and their resulting reactivity have been characterized. Complexes which activate the rings toward both nucleophilic addition and nucleophilic substitution reactions have been identified, and further reductions of the cyclic ligands have also been observed.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2003 with total page 812 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reactions of Dinuclear Molybdenum Sulfide Complexes with Nitriles and Isonitriles written by Paul Richard Bernatis and published by . This book was released on 1991 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalysis by Di and Polynuclear Metal Cluster Complexes written by Richard D. Adams and published by Wiley-VCH. This book was released on 1998-03-16 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt: A pioneer work on catalysis of organic chemical reactions involving multinuclear metal complexes. Catalysis by Di- and Polynuclear Metal Cluster Complexes surveys the latest developments at the frontier of this exciting field, combining theory with new and original examples of catalytic processes produced by polynuclear metal complexes. An invaluable resource for inorganic and organometallic chemists in industry and R&D, it contains chapters from world experts and scholars on: Concepts and models for characterizing homogeneous reactions catalyzed by transition metal cluster complexes Activation of ruthenium clusters for use in catalysis Catalysis by mixed metal clusters containing gold phosphine groupings Catalysis by sulfido bridged dimolybdenum complexes Dimolybdenum and ditungsten complexes Synthesis of organic compounds catalyzed by transition metal clusters Catalysis with dirhodium (II) complexes Catalytic synthesis of polythioether macrocycles Catalysis of Rh, Rh-Co, and Ir-Co multinuclear complexes and its applications to organic syntheses Bimetallic hydroformylation catalysis Catalysis by colloids Catalysis with palladium clusters Heterometallic clusters for heterogeneous catalysis Supported clusters in catalysis.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1989 with total page 896 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book The Synthesis of Dinuclear Molybdenum Complexes and Catalytic Reactions of Molybdenum Sulfido Complexes with Hydrogen written by Rohini T. Mehta Vohra and published by . This book was released on 1982 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1992 with total page 796 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 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 Chemical Abstracts written by and published by . This book was released on 2002 with total page 2540 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Summaries of FY Research in the Chemical Sciences written by and published by . This book was released on 1992 with total page 518 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Index to American Doctoral Dissertations written by and published by . This book was released on 1989 with total page 1252 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comprehensive Dissertation Index written by and published by . This book was released on 1989 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Faculties Publications and Doctoral Theses in Chemistry and Chemical Engineering at United States Universities written by American Chemical Society. Committee on Professional Training and published by . This book was released on 1991 with total page 1646 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comprehensive Coordination Chemistry II written by J. A. McCleverty and published by Elsevier Science. This book was released on 2004 with total page 900 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive Coordination Chemistry II (CCC II) is the sequel to what has become a classic in the field, Comprehensive Coordination Chemistry, published in 1987. CCC II builds on the first and surveys new developments authoritatively in over 200 newly comissioned chapters, with an emphasis on current trends in biology, materials science and other areas of contemporary scientific interest.
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1989-06 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ACS Directory of Graduate Research 1993 written by American Chemical Society. Committee on Professional Training and published by . This book was released on 1993 with total page 1700 pages. Available in PDF, EPUB and Kindle. Book excerpt:
