The conformational behavior and structure of monosubstituted-1,3,5-trisilacyclohexanes: 1-N,N-dimethylamino-1,3,5-trisilacyclohexane

Abstract 1-dimethylamino-1,3,5-trisilacyclohexane was synthesized and its structure and conformational properties have been determined by gas electron diffraction (GED) and quantum chemical (QC) calculations. The molecule may exist in 3 or 4 forms differing from each other by the substituents' position. QC results shows that the equatorial conformers are more stable than axial forms with ratio Eq:Ax=(75-58):(25-42)% (depending on method and basis set). From the GED data, the molar fractions of the conformers were found to be g-Eq:tr-Eq:tr-Ax=40(4):31(8):29(9)% at 272(3) K. In the liquid phase, as follows from IR measurements, the molecule may also exist in equatorial and axial forms.