Structures of Classical Reagents in Chemical Synthesis: (nBuLi)6, (tBuLi)4, and the Metastable (tBuLi · Et2O)2

Abstract

Crystalline nBuLi is also hexameric; this same degree of oligomerization was determined years ago in solutions of hydrocarbons. Six Li atoms form a distorted octahedron, six of whose triangular faces are capped by nBu groups (see structure depicted). The unusual arrangement of the -C atoms indicates interactions with the Li atoms. In contrast, tBuLi forms a Td-symmetric tetramer in the solid state.