Structural Diversity of Lithium Neopentoxide Compounds

The reaction of LiN(SiMe(3))(2) with 1 equiv of HOCH(2)CMe(3) (HONep) in toluene led to the formation of [Li(mu3-ONep)](8) (1). The complex adopts a novel dual-edge fused hexagon-square prismatic structure with a C(2v) 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(mu3)-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 ((6)Li, (7)Li, and (13)C) MAS and solution-state ((1)H, (7)Li, and (13)C) NMR studies were undertaken to verify the identity of the bulk powder and to determine the solution behavior of these compounds.