Synthesis, structure and solvatochromic properties of 5-(3- and 4-substituted phenylazo)-4,6-diphenyl-3-cyano-2-pyridones

Abstract

A series of some new pyridone arylazo dyes was synthesized from the corresponding diazonium salts and 4,6-diphenyl-3-cyano-2-pyridone using the classical reaction for the synthesis of the azo compounds. The structures of these dyes were confirmed by UV-vis, FTIR and 1H-NMR spectroscopic techniques. The solvatochromism of the dyes was evaluated with respect to visible absorption properties in various solvents. The effects of solvent dipolarity/polarizability and solvent/solute hydrogen bonding interactions were analyzed by means of the linear solvation energy relationship concept proposed by Kamlet and Taft. The 2-pyridone/2-hydroxypiridine tautomeric equilibration was found to depend on the substituents as well as on the solvents.