PHOTOCHEMISTRY IN POLYMERS - PHOTOINDUCED ELECTRON-TRANSFER BETWEEN PHENOSAFRANINE AND TRIETHYLAMINE IN PERFLUOROSULFONATE MEMBRANE

Absorption and emission properties of protonated and unprotonated forms of phenosafranine dye are investigated in the perfluorosulfonate ion-exchange membrane (Nafion) and polymer solution. Only the unprotonated form of phenosafranine is photoactive and undergoes electron transfer with triethylamine upon excitation with visible light. The triplet excited state of phenosafranine and the electron-transfer products in the Nafion film are characterized by laser flash photolysis with 532-nm excitation. In a dry evacuated film the triplet lifetime of phenosafranine is greater than 1.5 ms. During the steady-state photolysis, the semireduced dye undergoes disproportionation to accumulate a colorless two-electron-reduction product. © 1990 American Chemical Society.