SYNTHESIS AND CHARACTERIZATION OF ALKALI-METAL BIS(DIMETHYLSILYL)AMIDES - INFINITE ALL-PLANAR LADDERING IN THE UNSOLVATED SODINM DERIVATIVE

The synthesis of the bis(dimethylsilyl)amide complexes [MN(SiHMe2)(2)] (M = Li (1), Na (2), K (3)) was accomplished in high yield (>95%) by various standard procedures. Additionally, a novel trans-silylaminatio n reaction has been applied to synthesize the sodium derivative 2. The alkali metal amide complexes which are readily soluble in aliphatic h ydrocarbons were characterised by means of IR and H-1, C-13 and Si-29 NMR spectroscopy. A single crystal X-ray diffraction study of the sodi um derivative 2 revealed the formation of an infinite, all-planar ladd er structure. Compound 2 crystallizes from n-hexane at -35 degrees C i n the orthorhombic space group Pnma with a = 5.4439(2) Angstrom, b = 1 5.7268(9) Angstrom, c = 10.9751(6) Angstrom, V = 939.63(8) Angstrom(3) and Z = 4. Least squares refinement of the model based on 873 reflect ions converged to a final omega R-2 = 0.1124. (C) 1998 Elsevier Scienc e Ltd. All rights reserved.