Structural Diversity of Lithium Neopentoxide Compounds

The reaction of LiN(SiMe3)2 with 1 equiv of HOCH2CMe3 (HONep) in toluene led to the formation of [Li(μ3-ONep)]8 (1). The complex adopts a novel dual-edge fused hexagon−square prismatic structure with a C2v axis of
rotation that relates the top and bottom eight-membered rings. Substituting the noncoordinating solvent toluene
for a Lewis basic solvent (THF or py) led to the isolation of compounds of the general formula [Li(μ3-ONep)]4(solv)3, where solv = THF (2) or py (3). The cube structures of 2 and 3 have one Li which is not solvated
because of steric crowding of the ONep ligands. Multinuclear solid-state (6Li, 7Li, and 13C) MAS and solution-state (1H, 7Li, and 13C) NMR studies were undertaken to verify the identity of the bulk powder and to determine
the solution behavior of these compounds.