Anion-molecular interaction through CH₃ groups: modelab initio studies

Abstract

3-21G, 6–31G and 6–31+G calculations have been performed on Cl⁻...H₃CCl and LiCl...H₃CCl complexes with two different configurations each. Optimized geometries, stabilization energies, CH force constants and harmonic vibrational frequencies for CH₃Cl and its complexes are reported. Comparison of the calculated frequency shifts of CH-stretching bands of CH₃Cl, on complexation, with experimental results of related systems indicate that the interaction of Cl⁻ with CH₃ group takes place in a linear manner with the CH bond. A lower frequency shift for LiCl...H₃CX with reference to the Cl⁻...H₃CX complexes is explained on the basis of the reduction of the basicity of Cl⁻ ion in the presence of counter ion in the former complex considered.