Chemical Nuclear Polarization during the Photoreduction of Anthraquinones

The mechanism and products of the photoreaction of 2-isopropyl-9,10-anthraquinone ( 1 ) with ethanol have been established. An analysis of the signals of chemical nuclear polarization (CNP) showed that during the formation of CNP, only the mechanism of singlet-triplet transitions in radical pairs takes place without the participation of a triplet mechanism. In the study of the phase of multiplet and integral effects, the elementary acts of photoreaction were determined, and the structure of the anthrasemiquinone radical participating in the reaction was established.