Dimerization of α-methylstyrene via a photoexcited charge transfer complex

Abstract

The yields of α-methylstyrene dimers and polymer produced upon photoexcitation under rigorously dry conditions of the charge transfer complex formed from the monomer and an electron acceptor, pyromellitic dianhydride, in dichloromethane solution have been determined. The processes of formation are discussed in terms of the different kinds of reactive species, the excited charge transfer complex, the ion pair, and the free ion, which contribute to product formation depending on the polarity of the solution. The dimers were found to be produced form the excited charge transfer complex and the ion pair but not from the free ion, which exclusively produced polymer. On the other hand, polymerization is initiated both by the ion pair and the free ion.