Electron diffraction study of the molecular structure of n-methylbis(trimethylsilyl)amine in the gas phase

The molecular structure of NMe(SiMe3)2 in the gas phase has been determined by electron diffraction. The molecule has a planar NCSi2 skeleton with the SiNSi angle 129.4(6)°. Other important parameters (ra) are: r(Si–N) 171.9(4), r(Si–C) 187.5(3), r(C–N) 149.8(7) pm; angle CSiC 105.6(4)°. The steric requirements of the bulky SiMe3 groups are accommodated by the wide SiNSi and narrow CSiC angles, rather than by elongation of the Si–N bonds. The heavy-atom skeleton has C2 symmetry, with the SiMe3 groups twisted 35.2(5)° away from the positions in which one Si–C bond on each group eclipses the N–C bond, and this has the effect of minimising interactions between methyl groups on silicon and on nitrogen.