COMPARATIVE AB-INITIO CALCULATIONS ON SEVERAL SALTS

Ab initio calculations performed on three anions, substituted by stron g electron withdrawing groups CF3SO2, brought useful information on th e anion geometries and stabilities as well as on the charge delocaliza tion. Thus the carbanion exhibits a planar optimized geometry while, a ccording to HOMO values, the stability vs. oxidation is best for the i mide anion. Moreover the absolute hardness, calculated from the HOMO a nd LUMO energy levels, show that this latter is the hardest base among the three previous anions.