Photonics of Oxacarbocyanine Dyes in Complexes with Anionic Polyelectrolytes

摘要

The effect of interaction with anionic polymers (DNA, poly(sodium 4-styrenesulfonate), poly(acrylic acid)) was studied on spectral-fluorescent and photochemical properties of a number of oxacarbocyanine dyes: 3,3'-diethyloxacarbocyanine iodide (K1), 3,3'-diethyl-9-methyloxacarbocyanine iodide (K2), 3,3'-dimethyl-9-ethyloxacarbocyanine iodide (K3), 3,3',9-triethyl-6,6'-dimethoxy oxacarbocyanine iodide (K4), and 3,3',9-triethyl-5,5'-dimethyloxacarbo cyanine iodide (K5). A shift of the cis-trans isomer equilibrium toward the formation of the trans-isomsr was observed for meso-substituted oxacarbocyanine dyes in the presence of anionic polymers. The interaction of the dyes with anionic polymers leads to the formation of stable noncovalent complexes with a steep rise of fluorescence (due to binding of the trans-isomsr). Photoisomerization, thermal back isomerization, and spectral and kinetic properties of the triplet state of dyes K1, K3, K5 have been studied by the flash photolysis method in solutions and in complexes with DNA. The formation of complexes with DNA impedes photoisomerization and leads to an increase in the quantum yield of the triplet state of the dyes.