Linear and Cyclic Polysilanes Containing the Bis(trimethylsilyl)amino Group: Synthesis, Reactions, and Spectroscopic Characterization

The reaction of linear (SinCl2n+2; n = 3-5) and cyclic (Si5Cl10) perchloropolysilanes with 1 or 2 equiv of LiN(SiMe3)2 results in the formation of the bis(trimethylsilyl)amino derivatives (Me3Si)2NSi3Cl7 (1), (Me3Si)2NSi4Cl9 (2), (Me3Si)2N(SiCl2)nN(SiMe3)2 (n = 3, 4; n = 4, 5; n = 5, 6), cyclo-(Me3Si)2NSi5Cl9 (7), and cyclo-[(Me3Si)2N]2Si5Cl8 (8). 1-8 easily can be hydrogenated with LiAlH4 to give the corresponding amino and diamino polysilanyl hydrides. The monosubstituted and cyclic compounds 1, 2, 7, and 8 additionally afford Si -Si bond scission products, which cannot be separated in all cases. Chloro- and dichloro derivatives of Si3H8, n-Si4H10, and n-Si5H12 are obtained from the corresponding aminosilanes and dry HCl. All compounds were characterized by standard spectroscopic techniques. For Si-H derivatives the coupled 29Si NMR spectra were analyzed to obtain an unequivocal structural proof.