Bond dissociation energies of CF3-X bonds (X = C, O, N, S, Br): Ab initio molecular orbital calculation and application to evaluation of fire suppression ability

The C-X (X = C, O, N, S, Br) bond dissociation enthalpies (BDEs) of perfluo roalkanes, perfluoroethers, perfluorotrimethylamine, perfluorodimethyl sulf ide, and trifluoromethyl bromide were evaluated by the G2, G2MP2, and G2MS methods. Perfluoroethers had high BDEs of the C-O bond because of the stron g negative hyperconjugation between the CF3 group and lone pair orbitals of oxygen. The BDEs of CF3-X bonds could be used as an index of the fire supp ression ability.