Impact of Na- and K-C pi-interactions on the structure and binding of M-3(sol)(n)(BINOLate)(3)Ln catalysts

摘要

Shibasaki's heterobimetallic complexes M-3(THF)(n)(BINOLate)(3)Ln [M = Li, Na, K; Ln = lanthanide(III)] are among the most successful asymmetric Lewis acid catalysts. Why does M-3(THF)(n)(BINOLate)(3)Ln readily bind substrates when M = Li but not when M = Na or K? Structural studies herein indicate Na- and K-C cation-pi interactions and alkali metal radius may be more important than even lanthanide radius. Also reported is a novel polymeric [K-3(THF)(2)(BINOLate)(3)Yb](n) structure that provides the first evidence of interactions between M-3(THF)(n)(BINOLate)(3)Ln complexes.