SUPPORTED ELECTRON-ACCEPTOR AND ELECTRON-DONOR PHOTOSENSITIZERS FOR THE ACTIVATION OF BENZYLIC C-H OR C-X BONDS TOWARDS DIOXYGEN

Several electron-acceptor and electron-donor derivatives were grafted on silica and used as supported redox photosensitizers. The grafting w as performed by two methods: reaction of halogenated derivatives with aminopropyl silica; or condensation on silica of the compound which ha d been previously transformed into monochlorosilane. The series of pho tosensitizers produced corresponds to a light absorption range from 45 0 to 230 nm for electron acceptors and 700 to 230 nm for electron dono rs. The photosensitizers were used in test reactions to activate C-H a nd C-X bonds towards dioxygen. These reactions were the photosensitize d oxidative activation of 4-methyl anisole and the photosensitized red uctive activation of 4-nitrobenzyl bromide.