Catalytic Activation and Oxidation of C-H and C-C Bonds by Soluble Metal Complexes

这项由无机生物无机和金属有机化学计划支持的项目将支持宾夕法尼亚州立大学A.Sen教授对过渡金属、均相催化的继续研究。森教授将对两个新的催化系统进行深入研究，这两个系统有望实现有机分子的选择性、金属催化和氧化功能化。第一个体系是某些官能化有机化合物中铂(II)催化的远端C-H键的羟基化反应。第二种是以分子氧为氧化剂，用Rh催化的烷烃，包括甲烷和乙烷的C-H键和C-C键的羟基化和羟羰基化反应。催化剂前体不含可氧化配体，因此有可能不会发生催化剂降解。在这两种情况下都要解决的是有机金属中间体的结构和反应活性，C-H(C-C)活化步骤的性质，以及观察到的选择性的机理来源。这项研究涉及基于过渡金属的均相催化剂的开发，这种催化剂可能允许饱和碳氢化合物的选择性官能化。如果可以使用，均相催化反应通常比多相反应提供更高的选择性。然而，工业上只使用后一种类型的催化剂来促进饱和碳氢化合物的反应，因为已知的均相催化剂即使发生反应，通常也不具有足够的活性。这项研究所基于的初步发现表明，均相催化剂最终可能用于此类分子的选择性官能化。如果催化活性足够强，很可能会产生商业上可行的过程。

This project supported by the Inorganic Bioinorganic and Organometallic Chemistry Program will support the continuation of studies of transition metal, homogeneous catalysis by Professor A. Sen of the Pennsylvania State University. Professor Sen will perform in-depth investigations of two new catalytic systems that offer promise for selective, metal catalyzed, oxidative functionalization of organic molecules. The first of these systems is the platinum(II) mediated hydroxylation of remote C-H bonds in certain functionalized organic compounds. The second is the rhodium catalyzed hydroxylation and hydroxycarbonylation of C-H and C-C bonds of alkanes, including methane and ethane, using molecular oxygen as the oxidant. The catalyst precursors contain no oxidizable ligands so that there is the possibility that catalyst degradation will not occur. To be addressed in both cases are the structure and reactivity of the organometallic intermediates, the nature of the C-H (C-C) activation step, and the mechanistic origins of the observed selectivities. This research is concerned with the development of homogeneous catalysts based upon transition metals that may allow for the selective functionalization of saturated hydrocarbons. Homogeneously catalyzed reactions typically offer much greater selectivity than heterogeneous reactions, when they can be used. However, only the latter types of catalysts are used industrially to promote reactions of saturated hydrocarbons because known homogeneous catalysts normally are not sufficiently reactive, if they even react. The initial discoveries upon which this research is based suggest that homogeneous catalysts may ultimately be used for the selective functionalization of such molecules. If the catalytic activities are great enough, there is a high probability that commercially viable processes will result.