Cooperative Catalysis: Large Rate Enhancements with Bimetallic Rhodium Complexes

A large increase in reaction rate was observed for the catalyzed mono- and dihydroalkoxylation of alkynes when structurally constrained bimetallic Rh­(I) catalysts with imidazolyl-imine ligands were compared to their monometallic analogues. The “cooperative” enhancement was vastly improved by restricting the conformational freedom of the bimetallic structure and minimizing the intermetallic Rh···Rh distance.当将带有咪唑亚胺配体的结构受限双金属铑(I)催化剂与其单金属类似物进行对比时，研究观察到催化炔烃的单氢烷氧基化与二氢烷氧基化反应的速率大幅提升。通过限制双金属结构的构象自由度并最小化金属间铑-铑间距，该“协同增强”效应得到了显著改善。