SOLVATION EFFECTS ON DIRADICALS AND ZWITTERIONS - TETRAMETHYLENES ANDTRIMETHYLENES

A solution model previously implemented in the semiempirical molecular orbital method SINDO1 is applied to the study of trimethylenes and te tramethylenes in different solvents. It is shown that diradical trimet hylenes and tetramethylenes are polarized by the solvent. This influen ce of the solvent can also lead to a zwitterionic state in cases where a diradical is predicted without the solvent. Solution effects are th e reason for the discrepancy between the experimentally observed polym erization mechanisms of substituted tetramethylenes and gas phase calc ulations. For a prediction of the correct state, a geometry optimizati on in solution is important.