Green-Light-Induced Cationic Ring Opening Polymerization Reactions: Perylene-3,4:9,10-bis(Dicarboximide) as Efficient Photosensitizers

New perylene-3,4:9,10-bis(dicarboximide) (PBI) photoinitiators/photosensitizers derived from perylene-3,4:9,10-tetracarboxylic dianhydride are synthesized and investigated for the formation of free radicals under air and under very soft irradiation (i.e., halogen lamp) or laser diode exposure at 532 nm. Such a PBI in combination with a diphenyl iodonium salt and N-vinylcarbazole or a silane very efficiently promotes the ring-opening polymerization of epoxides and can also generate acrylate/epoxide interpenetrated polymer networks. It partly behaves as a metal-free organic photocatalyst operating in an oxidative catalytic cycle. The different chemical intermediates are characterized by ESR and laser flash photolysis experiments. The mechanisms involved in the initiation step are discussed.