STRUCTURES AND DYNAMICAL BEHAVIOR OF 2 BI S[LITHIO(TRIMETHYLSILYL)AMINO]SILANES

NMR-spectroscopic studies on solutions as well as X-ray structural inv estigations of the solids reveal that both Me2Si[N(Li)SiMe3]2 (1) and (Me3Si)2N-SiH[Me3SiN(Li)]2 (2) are dimeric molecular compounds in both phases. Moreover, in spite of their different reactivity and constitu tion, the Li, N, and Si atoms of both dimers from similar ''basketshap ed'' molecular cages in the solid state. H-1-, Li-6/7-, and C-13-NMR s pectra in toluene show temperature dependence which is ascribed to int ramolecular bond fluctuations within the molecular cages causing an eq uilibration of the two enantiomers of both compounds which cocrystalli ze in the solid state. The different activation energies for the motio ns of 1 and 2, which are deduced by inspection of the spectra, can be explained by participation of the hydride hydrogen in the intramolecul ar process in 2.