Collect. Czech. Chem. Commun. 1982, 47, 3199-3205

MNDO conformations of chloromethyloxirane and solvent effect

Igor Tvaroška

Chemical Institute, Slovak Academy of Sciences, 842 38 Bratislava


Structure of chloromethyloxirane during rotation around the C-C single bond connecting oxirane ring and chloromethyl group has been studied theoretically in twelve solvents. Molecular characteristics and energy of the isolated molecule have been calculated by the semi-empirical MNDO method of molecular orbitals. The MNDO calculation predicts the existence of only two synclinal conformers G-1 and G-2, more stable being the less polar G-2, μ = 2.39 . 10-30 mC. However, the calculation carried out for dilute solutions including the solvation energy by the method of continuum reveals the presence of the third, antiperiplanar conformer T, μ = 9.26 . 10-30 mC. Populations of the individual conformers depend considerably on solvent, the most stable in ethanol being G-1, μ = 11.06 . 10-30 mC. The results obtained are compared with experimental data and also discussed from the point of view of the gauche effect.