Spectral-luminescent properties of γ-pyrilocyanines and their heteroanalogs with modified complex anions

Abstract

Spectral-luminescent properties of γ-pyrilocyanines and their heteroanalogs with modified complex anions have been studied. It was shown that the fluorescence quantum yield in the series pyrilo-, thiapyrilo-, and selenopyrilocyanine decreased for mono-and trimethinecyanines as well as through substitution of TlCl 4 − for. This is likely due to the increased probability of singlet-triplet transfers under the influence of heavy atoms.Introduction. Polymethine dyes are unique transformers of visible and IR light [1] and are widely used as photosensitizers [2,3], lasing materials [4,5], photoresists, and new media for information storage. Relationships between the chemical structure of the dye and its spectral-luminescent properties must be established in order to discover effectively dyes that are capable of purposeful transformation of light energy. This requires a comprehensive approach to the study of spectral-luminescent properties, e.g., investigation of electronic absorption spectra, luminescence spectra, luminescence quantum yields, excited state lifetimes, and other properties.The goal of our work was to study features of the spectral-luminescent properties of γ-pyrilocyanines and their heteroanalogs as a function of the structure of the dye anion and cation.Experimental. We investigated pyrilium, thiapyrilium, and selenopyrilium dyes of general formula R + Y -: