1-Dimethylamino-1-silacyclohexane: Synthesis, molecular structure and conformational behavior by gas-phase electron diffraction, Raman spectroscopy and detailed quantum chemical calculations

Abstract 1-(N,N-dimethylamino)-1-silacyclohexane 1 was synthesized. Contributions of the conformers of 1, Eq- trans : Eq- gauche : Ax- trans , were found to be 55(15):15(15):30(15) mol.% in gas phase at 288 K from gas electron diffraction. The enthalpy Δ H  = 0.29(15) kcal/mol for Ax-to-Eq transition was measured by temperature dependent Raman spectroscopy of liquid 1 and its solutions. Geometry, conformational properties and intramolecular conversion were explored by theoretical calculations. The nitrogen bond configurations for 1 was found to be close to planar, with a sum of the bond angles of ca. 350-355° that is quite different from those analogs in which the N atom is connected to a carbon atom rather than to a silicon atom.