Isolation and structural characterization of unsolvated lithium aryls

Abstract

The synthesis and characterization of three examples of unsolvated lithium aryls are described. The compounds (Li(Trip)} 4 (1, Trip=2,4,6-i-Pr 3 C 6 H 2 ), (Li(2,6-Mes 2 C 6 H 3 )} 2 (2, Mes= 2,4,6-Me 3 C 6 H 2 ), (Li(n-Bu)) 2 (LiMes * ) 2 (3), and (Li(n-Bu)} 2 (LiMes * ) 2 -Mes * Br(3-Mes * Br, Mes * =2,4,6-t-Bu 3 C 6 H 2 ) were synthesized by a metal-halogen exchange reaction between n-butyllithium and the appropriate aryl bromide (1 and 3) or iodide (2). The X-ray crystal structures of 1 and 3 show that they are tetrametallic lithium species involving almost planar arrays of four lithium atoms