Structure and spectral-luminescent properties of polymethine dyes

The review considers the influence of the length of the polymethine chain, the structures of the hetero-radicals, the nature of substituents, electronic asymmetry, interactions of chromophores, structures of ion-pairs, photochemical reactions with proton transfer, and concentration, on the spectral-luminescent properties of polymethine dyes. The characteristic features of these properties in low-polarity media, including polymeric matrices, are discussed. Solvatochromism and solvatofluorochromism of polymethines are considered. Major factors influencing changes in the spectral-luminescent properties of cyanines, in relation to their structure and the nature of the medium, are revealed. Possible applications of polymethines to the solution of various problems connected with the transformation of light energy are discussed. The bibliography includes 231 references.