The structure of NMe2(SiMe3) has been studied in the crystalline phase at 116 K by X-ray crystallography and in the gas phase at 295 K by electron diffraction. The solid phase structure consists of essentially isolated molecules with a Si-N bond length of 1.719 4(12) Å. The geometry at silicon is nearly tetrahedral and that at nitrogen is slightly non-planar, with angles CNC 111.95(12), SiNC 122.92(10) and 122.91(10)°. The molecule possesses non-crystallographic Cs symmetry and the N-bonded methyl groups are distorted from planarity towards the unique Si-bonded methyl group, which is bent back to give an NSiC angle of 113.93(6)°. The conformation of the Si-methyl groups is such that one CH vector of each is approximately parallel to the NSi direction; for those bonded to nitrogen, one CH bond of each lies close to the CSiN plane. In the vapour the SiNC2 skeleton was found to be planar. Principal parameters (ra) are: r(Si-N) 1.710(5), r(Si-C) 1.868(4), r(C-N) 1.462(4) Å; angles SiNC 121.4(5), NSiC 110.3(7), CNC 117.1(10)°. The molecule is distorted from Cs symmetry by a 9.6(20)° twist of the SiMe3 group and by twists of -12.1(45)° for each of the methyl groups on silicon.
|Number of pages||5|
|Journal||Journal of the Chemical Society, Dalton Transactions|
|Publication status||Published - 1986|
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