Bond dissociation energies of antioxidants

A simple experimental method for the determination of the acidic H-A bond dissociation energy (BDE) derived from a thermodynamic cycle, has been reviewed. This method is based on measurements of the equilibrium acidities of the molecules and the oxidation potentials of their conjugate anions in dimethyl sulfoxide (DMSO) solution. The BDEs of the O-H bonds in various phenols, the N-H bonds in various anilines and the S-H bonds in various thiophenols have been determined by this method. These results provide quantitative information about the hydrogen atom transfer effectiveness of the antioxidants used in industry and found in biological systems. The BDEs determined by this simple experimental method are accurate to +/- 8.5 kJ/mol. (C) 1997 Elsevier Science Limited.