Rotational isomerism in ortho-substituted (benzoyloxymethyl)trifluorosilanes containing a pentacoordinated silicon atom

Abstract

1. In the gaseous state and in an organic solvent ortho-substituted (benzoyloxymethyl)-trifluorosilanes 2-X-C6H4COO·CH2SiF3 (X=Cl, OMe) exist as mixtures of rotational isomers with the cis and trans orientation of the substituent X and the carbonyl group. In solution both isomers contain an intramolecular coordination bond. 2. The value of the parameter B, which characterizes the dipole-dipole interaction between the compounds and the medium, is larger for the cis isomer of the methoxy derivative than for the less polar trans isomer. The contribution from the induction and orientation components to the energy of the van der Waals interaction between the investigated molecules and the medium was estimated on the basis of the temperature dependence of the parameter B.