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

在无机、生物无机和有机金属化学项目的支持下，麻省理工学院的Richard Schrock教授将继续他对含有金属-氮和金属-碳多键的化合物的化学研究，重点是它们作为功能化烯烃的复分解催化剂。最令人感兴趣的金属是钼和铼。确定配体对催化剂活性影响的动力学和机理研究将在催化剂的开发中发挥核心作用。最近发现的聚亚胺锇配合物和含有铼-铼双键的化合物的化学性质将作为该项目的一部分进行探索；在这两类新化合物中，金属原子都只有两个d电子。最后，将开始研究钌在+6氧化态下的金属-碳多键化学的发展。烯烃复合反应是指含有碳碳双键的化合物中取代基的成对置乱反应，是一种用途极为广泛的反应，具有重要的技术意义。更广泛地使用这种反应的一个最大缺点是，当双键的碳原子上附着氢或烷基以外的基团时，已知的催化剂无法促进反应。该项目的一个主要目标是开发用于此类烯烃复分解的实用催化剂。这项工作的其他方面是针对具有不寻常结构和/或金属原子具有不寻常氧化态的新化合物的合成。

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.