Phosphonium-Bridged Alkali and Alkaline-Earth Metallocene Complexes¹

Abstract

Chiral metallocene complexes with a dialkylphosphonium bridge and different main-group metal (Li, K, Ba) centers have been synthesized from phosphonium-bridged bis(cyclopentadienyl) ligands in their mono- and diprotonated forms. NMR studies in solution and crystal structures of the kalocene Me2P(2-Me-4-tBu-C5H2)2K and of the barocene Me2P(2-Me-4-tBu-C5H2)2Ba(THF)3+BPh4- show that these metallocenes are obtained in form of their racemic diastereomers.