PHOTOCHEMISTRY OF BENZIMIDAZOLOCYANINE DYES IN SOLVENTS OF DIFFERENT POLARITY

The effect of ion pair formation on the kinetics of the decay of the p hotoisomers and triplet states of cationic benzimidazolocyanine dyes i s studied by flash photolysis. An increase in the rate constant of the reverse cis-trans isomerization of the photoisomers is observed when ion pairs are formed (in nonpolar solvents). In the case of benzimidaz olocyanine dyes with the I- anion, ion-pair formation causes an increa se in the rate constant of decay of the triplet state. Acceleration of S1 --> S0 internal conversion is discovered for the dyes with I-.