Substituent and solvent effects on the dipole moments and photophysical properties of two azo sulfonamide dyes

Absorption and emission spectra of two azo sulfonamide dyes with different substituent, and size of lateral groups have been studied in different solvents. The solvatochromic method was used to investigate the dipole moments of these dyes in ground and excited states. In order to understand the effect of specific and non-specific interactions on the spectral behavior of these dyes and to conceive nature and extend of solvent–solute interactions, the dyes spectral features were analyzed by the linear solvation energy relationships concept.