Impact of Na- and K-C π-Interactions on the Structure and Binding of M_3(sol)_n(BINOLate)_3Ln Catalysts

摘要

Shibasaki's heterobimetallic complexes M_3(THF)_n(BINOLate)_3Ln [M = Li, Na, K; Ln = lanthanide(III)] are among the most successful asymmetric Lewis acid catalysts. Why does M_3(THF)_nBINOLate)_3Ln readily bind substrates when M = Li but not when M = Na or K? Structural studies herein indicate Na- and K-C cation-π interactions and alkali metal radius may be more important than even lanthanide radius. Also reported is a novel polymeric [K_3(THF)_2(BINOLate)_3Yb]_n structure that provides the first evidence of interactions between M_3(THF)_n(BINOLate)_3Ln complexes.