Spin trapping studies of photochemical reactions

Abstract

Spin trapping is a very useful technique to study the photochemistry of chemical photosensitizers that undergo electron or hydrogen-transfer (Type I) reactions upon UV or visible irradiation. The Type I photochemistry of chlorpromazine [2-chloro-N-(3-dimethylaminopropyl)-phenothiazine], 3,3‘ 4’ 5-tetrachlorosalicylanilide and 3, 4 ’, 5-tribromosalicylanilide has been investigated using 2-methyl-2-nitrosopropane (MNP) and 5, 5-dimethyl-1-pyrroline-N-oxide (DMPO) as spin traps. All compounds underwent dehalogenation upon UV-irradiation and the resultant aryl radicals were trapped and identified. © 1990 De Gruyter