Pseudorotation as a mechanism for intramolecular electron density transfer. Fragmentation of the octafluoronaphthalene radical anion

Adiabatic potential energy surface (PES) of the octafluoronaphthalene radical anion (RA) has been investigated with the B3LYP/6–31 + G* calculations for the gas phase and polar media. In spite of the low symmetry of the RA its PES has been found to be the surface of pseudorotation. The pseudorotation is a way of intramolecular electron density transfer and so played the key role in regioselectivity of the RA fragmentation through the fluoride ion elimination. Transition states for α and β CF bond cleavage in the polar solvent were located. The noticeably lower energy barrier for the β CF bond cleavage explains the observed regioselectivity of the octafluoronaphthalene reductive defluorination.