ORGANOTRIALKOXYALUMINATES AND ORGANOTRIFLUOROALUMINATES - CRYSTAL-STRUCTURES OF LI[(ME(3)SI)(3)CALX(3)]CENTER-DOT-OC4H8 (X=(T)BUO, F)

Reactions of the organotrihydroaluminate Li-[(Me(3)Si)(3)CAlH3]. 2THF, (THF = tetrahydrofuran) with the protic reagents (t)BuOH or HF in tol uene yield the novel compounds Li[(Me(3)Si)(3)CAlX(3)]. THF, X = (t)Bu O or F, which crystallize as a monomer and a tetramer, respectively. M ultinuclear NMR measurements on the latter show that the tetrameric st ructure is broken down in THF but preserved in benzene; the [(Me(3)Si) (3)CAlF3] fragments rotate on the NMR time scale about the body diagon al of the Al4Li4 cube.