Mixed Crystalline Lithium Organics and Interconversion in Solution

Scrambling, but not the Humpty Dumpty way! The crystallographically confirmed mixed lithium organic [tBuLi]4·4­[Me2NC6H4Li]4 (1) consists of independent alkyl- and aryllithium tetramers in a 1:4 ratio. It has been employed to study the interconversion in solution. 7Li-DOSY and 7Li-EXSY NMR spectroscopy was utilized to establish the nature of that exchange and to determine related rate constants along the equilibria to give [Me2NC6H4Li]4 (A), [(Me2NC6H4Li)3(tBuLi)] (B), [(Me2NC6H4Li)2(tBuLi)2] (C), [(Me2NC6H4Li)­(tBuLi)3] (D), and [tBuLi]4 (E).