SIN COMPOUNDS 156 PREPARATION AND PROPERTIES OF CYCLIC SILYLAMIDES OF BERYLLIUM - CRYSTAL AND MOLECULAR-STRUCTURE OF DIMERIC DIAZA-SIDILA-BERYLLA-CYCLOHEXANE

Four novel cyclic beryllium silylamides (I-IV; R = CH3) were obtained by reaction of BeMe2 with the appropriate aminosilanes. In solution and in the solid state they form dimers and probably higher associated oligomers, which, {A figure is presented} according to their 1H NMR spectra, interconvert depending on temperature and solvent. Crystallic II dimerizes via a centrosymmetric BeNBe′N′ four-membered ring, the BeN and BeN′ distances being 1.714(3) and 1.683(3) Å. The CN and SiN bonds of the tetracoordinate N atom (1.502(3) and 1.752(3) Å) are longer than those formed by the tricoordinate N atom (1.473(3) and 1.722(2) Å); the BeN (tricoordinate N) distance is 1.550(4) Å. © 1979.