Enantiomerization of Environmentally Significant Overcrowded Polychlorinated Biphenyls (PCBs)

The rotational barriers of overcrowded PCBs are predicted by ab initio methods including electron correlation, thus settling the controversy between theory and experiment. For 2,2′,3,3′,4,6′-hexachlorobiphenyl ( PCB 132 ), an enantiomerization barrier of 185 kJ/mol is calculated by B3LYP/6-31G*, in excellent agreement with the experimental data. Chirality 9:350–353, 1997. © 1997 Wiley-Liss, Inc.