Chemically induced dynamic electron polarization. Part 8.—Simultaneous operations of the radical-pair and photoexcited triplet mechanisms in the photolysis of substituted benzoquinone, naphthoquinone and anthraquinone

Abstract

CIDEP in the photoreduction of various quinones by 2,6-di-t-butylphenol in solution was observed. The dependence of polarization on individual hyperfine lines as well as on g factor difference was systematically studied. Experimental facts point to the coexistence of both the radical pair and the phototriplet mechanisms in these quinone systems with the phototriplet mechanism being the major contributor to the observed CIDEP. The isotope effect in the photoreduction supported the phototriplet mechanism.