title: Involvement of triplet excited states and olefin radical cations in electron-transfer cycloreversion of four-membered ring compounds photosensitized by (thia)pyrylium salts.
abstract: Cycloreversion of 1,2,3,4-tetraphenylcyclobutanes 1a,b and oxetane 2 is achieved using (thia)pyrylium salts as electron-transfer photosensitizers. Radical cation intermediates involved in the electron-transfer process have been detected using laser flash photolysis. The experimental results are consistent with the reaction taking place from the triplet excited state of the sensitizer.
authors.affiliation: Departamento de Química, Instituto de Tecnología Química UPV-CSIC, Universidad Politécnica de Valencia, Camino Vera s/n, Apartado 22012, 46022, Spain. mmiranda@qim.upv.es
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Miranda
authors.forename: M Angeles
authors.initials: MA
authors.lastname: Izquierdo
authors.forename: Francisco
authors.initials: F
authors.lastname: Galindo