STUDIES ON SOLVENT DEPENDENCE OF ABSORPTION-BANDS OF SOME SELECTED CYANINE DYES

The solvent dependence of the short-wavelength absorption bands of sel ected cyanine dyes incorporating 1H-pyrazolo[4,3-d]-[1,2,3]oxadiazole moiety was studied in the visible region. The spectra show a complex c harge transfer CT transition and the assignments are based on solvatoc hromic behaviour of this transition. The absorption spectra in buffer solution have been also utilized to select the optimal pH value at whi ch they can be applied as photosensitizers.