Absorption and emission spectra of three hetarylazoquinoline compounds with different substituents
were examined in liquids and liquid crystalline solvents for the first time. The spectral features of the
hetarylazoquinoline dyes were explained according to azo/hydrazone tautomerism in conjunction with
the solvatochromic characteristic of the preferred tautomer. The nature and extent of soluteesolvent
interactions were described using KamleteTaft and Katritzky multiparameter polarity scales. It was
observed that solvatochromic azo/hydrazone tautomerism depend on multiple solute-solvent interactions,
in particular on specific interactions and the solvent ability to transport the hydrogen atom through
the media. In addition, it was concluded that anisotropic hosts prevent shift of the tautomeric equilibrium
toward the hydrazone form.
