Trimethyl-aluminium and -gallium derivatives of calix[4]arenes: cone (mono-metallic) or doubly flattened partial cone (tetrametallic) conformations

Abstract

Reaction of calix[4]arene (H₄L) or p-Bu^t-calix[4]arene (H₄L′) with MMe₃(M = Al, Ga) in toluene affords fully deprotonated, alkyl-metal rich complexes [(L or L′)(M-Me)₂(MMe₃)₂] with the calixarene adopting a doubly flattened partial cone conformation; reaction of 1,3-dimethyl ether p-Bu^t-calix[4]arene (H₂L″) with AlMe₃ yields [(L″)AlMe], the metal-bound alkyl group exo to the cavity of the calixarene in a cone conformation.