Dilithiated salen complexes: chiral [(salen)Li2·hmpa]2 and deliberate partial hydrolysis to give [(salen)Li2]3·Li2O·2tmen·H2O [H2salen =N,N′-ethylenebis(salicylideneimine); hmpa = hexamethylphosphoramide; tmen = tetramethylethylenediamine]

Abstract

Chiral [(salen)Li₂·hmpa]₂ has a Li₄O₄ cubane-type core in the solid but low-temperature NMR spectroscopy reveals a racemisation equilibrium in solution; deliberate addition of H₂O to [(salen)Li₂]_n in the presence of tmen produces a species having two Li₄O₄ cubes sharing a common oxygen and containing tmen ligands acting in a hitherto unobserved monofunctional mode.