Multiple Metal-Carbon Bonds, Metallacycles, and Catalytic Reactions Involving Olefins and Acetylenes

点击翻译按钮获取中文摘要

With support from the Inorganic, Bioinorganic and Organo- metallic Chemistry Program, Professor Richard Schrock of MIT will continue his research on the chemistry of compounds that contain metal-nitrogen and metal-carbon multiple bonds with emphasis on their use as metathesis catalysts for function- alized olefins. The metals of most interest are molybdenum and rhenium. Kinetic and mechanistic studies to determine the effects of coordinated ligands on catalyst activity will play a central role in the catalyst development. The chemistry of recently discovered polyimido osmium complexes and compounds that contain rhenium-rhenium double bonds will be explored as part of this project; in both of these new classes of compounds the metal atoms have only two d-electrons. Finally, studies directed toward the development of metal-carbon multiple bond chemistry of ruthenium in the +6 oxidation state will be initiated. %%% Olefin metathesis, which refers to pairwise scrambling of substituents in compounds that contain carbon-carbon double bonds, is an extremely versatile reaction with great tech- nological significance. The single biggest drawback to even greater use of this reaction is the failure of known catalysts to promote the reaction when there are groups other than hydrogen or alkyl attached to the carbon atoms of the double bond. A primary objective of this project is to develop practical catalysts for metathesis of such olefins. Other aspects of the work are directed to the synthesis of new compounds with unusual structures and/or in which the metal atoms have unusual oxidation states.