EXCITATION OF CHEMILUMINESCENCE IN A MODEL REACTION OF DIPHENYLMETHANE OXIDATION - EVALUATION OF THE EFFICIENCY AND SEMIEMPIRICAL CALCULATIONS

The absolute yields (Phi) of excitation of the triplet benzophenone, a product of disproportionation of peroxyls in the chemiluminescent ox idation reaction of diphenylmethane, were measured. The Phi value is independent of the temperature and viscosity of the medium, but decrea ses with increase in its polarity: it is 0.003 in CCl4 and 0.0015 in M eCN. Semiempirical MNDO calculations of the structure of intermediates and the energy profile of their decomposition were carried out. A con clusion was made that the excitation of the (3)n pi. state of the ket one occurs during the decomposition of the intermediate tetroxide Ph(2 )CHOOOOCHPh(2) after the transition state, but before isolation of the Ph(2)COOO biradical, which thereafter decomposes to benzophenone and O-2.