Photochemistry and Applications of Cyanine Borate IR Dyes

Photoreduction of cyanine borate ir dye gave the corresponding meso-substituted leuco cyanine. One electron transfer from borate to the cyanine molecule in excited state, followed by recombination of the dye radical with the alkyl or phenyl radical, produced from n-butyl triphenylborate as a counter anion, gave the leuco dye. This photoreaction process can be applied as a photopolymerization of monomers induced by ir irradiation, and a photodecolorizable tonner for electrophotography.