Zu Struktur und dynamischem Verhalten zweier Bis[lithio(trimethylsilyl)amino]silane

Abstract

NMR-spectroscopic studies on solutions as well as X-ray structural investigations 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 constitution, the Li, N, and Si atoms of both dimers from similar "basketshaped" molecular cages in the solid state. H-1-, Li-6/7-, and C-13-NMR spectra in toluene show temperature dependence which is ascribed to intramolecular bond fluctuations within the molecular cages causing an equilibration of the two enantiomers of both compounds which cocrystallize in the solid state. The different activation energies for the motions of 1 and 2, which are deduced by inspection of the spectra, can be explained by participation of the hydride hydrogen in the intramolecular process in 2.