Time-resolved ESR study of electron transfer process between phenothiazine and maleic anhydride

Abstract

The electron transfer reaction between phenothiazine (PTH) and maleic anhydride (MA) as well as the related chemically induced dynamic electron polarization (CIDEP) effect has been investigated by time-resolved electron spin resonance (TRESR). The CIDEP spectra assigned to the anion radical (MA −) of maleic anhydride reveal that the reaction takes place in the excited triplet state of PTH. The electron transfer rate constant k ET and the spin-lattice relaxation time 3 τ 1 of the excited triplet state of PTH are 3 × 10 8 M −1 s −1 and 10 −7 s, as obtained from our TRESR experiment.