T. Fjeldberg, R. Andersen
Apr 1, 1985
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Influential Citations
24
Citations
Journal
Journal of Molecular Structure
Abstract
Abstract Gaseous tris (bis(trimethylsilyl)amido)scandium, Sc{N(SiMe3)2}3, has been studied by electron diffraction at a nozzle temperature of ca 450 K. The diffraction data are consistent with monomeric molecules of approximately D3- symmetry: the ScN, skeleton is essentially planar (∠NScN = 119.5(1.5)°), and the twist of the NSi2 groups relative to the ScN2 plane is 55(2)°. Other key parameters, including bond lengths (ra) and valence angles are: r(ScN) = 2.02(3) A, r(SiN) = 1.715(8) A, r(SiC) = 1.881(4) A; ∠ScNSi = 116.0(1.0)°, ∠SiNSi = 128.0(2.0)°, ∠NSiC = 110.7(1.0)° and ∠SiCH = 112.3(1.8)°. The SiMe3 groups are twisted 12(3)° away from the positions typified by one SiC bond of each such group being anti to the adjacent SiN bond, and the methyl groups themselves may be twisted about 20° away from their staggered reference positions. The crystal structure, solved by Ghotra et al, is a variance with the gas-phase structure as it reveals a pyramidal ScN3 skeleton; this probably illustrate the effects of crystalpacking forces in the solid phase.