A preliminary quantum‐chemical study of the mechanisms for the reactions of perchlorofluoroethanes with nucleophiles initiated by chlorophilic attacks

A preliminary theoretical study of the mechanisms for the reactions of the perchlorofluoroethanes CF 2 ClCCl 3 ( 1 ), CF 2 ClCCl 2 F ( 2 ) and CF 3 CCl 3 ( 3 ), with nucleophiles has been carried out by the MNDO method, following the experimentally suggested process shown in Scheme 1. The unlikely chlorophilic attack in the first step of Scheme 1 has been shown to be feasible for 1 , 2 and 3 by analysis of the MO interactions. The second step has been found to be affected by the anionic hyperconjugation which stabilizes the anions CF 2 ClCCl   2 −( 4 ), CF 2 ClCClF − ( 5 ) and CF 3 CCl   2 −( 6 ) and would make reactions (2) (the second step) unfeasible in gas phase, but in solution reaction (2) may still easily occur for 4 and 5 .