Development of Novel Heterogeneous Ruthenium Catalysts for Environmentally-benign Organic Transformations

高度期望开发对环境友好的、高原子效率的有机转化有效的新型固体催化剂。本文研究了CeO_2或ZrO_2负载的钌催化剂，它们在稳定芳香C-H键的直接芳基化和烷基化、稳定C-C键的断裂和重构的烯丙基转移反应、羧酸与炔的区域和立体选择性加成、不饱和烃的选择性交叉偶联、以及通过氨基醇的缩合环化反应合成吲哚。这些催化剂是可回收的而不损失显著的活性，并且Ru物质浸出到溶液中是可忽略的。光谱学研究表明，E. G. XAFS和FTIR研究表明，在氧化铈表面形成了畸变的Ru=O物种，这些物种将原位转化为低价活性Ru物种。

The development of novel solid catalysts effective for environmentally benign, highly atom-efficient organic transformations is highly desired. In the present study, CeO2-or ZrO2-supported ruthenium catalysts which are quite effective for the direct arylation and alkylation of stable aromatic C-H bond activation, the allyl transfer reactions via the cleavage and reconstruction of stable C-C bonds, the regio-and stereoselective addition of carboxylic acids to alkynes, the selective cross-coupling of unsaturated hydrocarbons, and the synthesis of indole via the dehydrogenative cyclization of an amino alcohol have been developed. These catalysts are recyclable without loss of significant activities, and the leaching of Ru species into solution is negligible. The spectroscopic studies, e. g. XAFS and FTIR studies, have revealed the formation of distorted Ru=O species on the surface of ceria, which would be transformed to low-valent active Ru species in situ.