Synthesis and X-ray structures of tetralithium derivatives of tert-butylcalix[4]arene containing unique Li–O cores based on a square-pyramidal geometry

Abstract

Tetralithiation of tert-butylcalix[4]arene in the presence of hmpa (hexamethylphosphoramide) results in the isolation of either a monomeric complex in which LiOH is incorporated into an Li ₅ O ₅ core based on an isolated square pyramid of Li atoms, or a dimeric LiOH-free species containing an Li ₈ O ₈ core in which the same structural motif is maintained by edge-sharing of two square pyramids of Li atoms.