The investigation of consecutive micellised radical pairs by the method of stimulated nuclear polarization

Abstract

The main features of stimulated nuclear polarization (SNP) formation in consecutive micellised radical pairs (RP) have been studied both experimentally and theoretically. The photolyses of dibenzyl ketone (DBK), α-methyldibenzyl ketone (MDBK), and 2,2′,4,4′-tetramethyldimethyl acetone dicarboxylate (PEST) in aqueous solutions of alkylsulfate micelles have been used as model photoreactions. The rate constants of relaxation and RP escape from micelles have been obtained. SNP spectra of consecutive micellised RPs have been compared to the spectra of consecutive biradicals with similar structure of radical centers and chain length equal to the inner diameter of the micelle. It has been shown that the significant difference in the SNP spectra of micellised RPs and biradicals is determined by the difference in their molecular dynamics and rate of reencounters.