Photolysis of N-phenylglycines sensitized by polycyclic aromatic hydrocarbons -: Effects of sensitizers and substituent groups and application to photopolymerization

The effects of sensitizers and substituent groups on the rate of sensitized photodecomposition of N-phenylglycine (NPG) were investigated under irradiation using light of 366 nm. It was found that pyrene was the most effective polycyclic aromatic hydrocarbon as a sensitizer for the NPG photodecomposition. Introduction of an electron-donating group into the aromatic ring of NPG resulted in the enhancement of the pyrene-sensitized photodecomposition rate. Especially, the photodecomposition rate of N-(2,4-dimethylphenyl)glycine was larger than that of parent NPG by a factor of 4.6. The results were discussed on the basis of the free-energy change for the electron transfer from NPG or its derivatives to the excited sensitizer. Furthermore, the pyrene-sensitized photodecomposition of NPGs could be utilized for a photoinitiator for free radical polymerization of acrylate monomers. (C) 2002 Elsevier Science B.V. All rights reserved.