Solvatochromism of 5-(4-substituted arylazo)-4-phenyl-6-methyl-3-cyano-2-pyridones

Abstract

Eight 5-(4-substituted arylazo)-4-phenyl-6-methyl-3-cyano-2-pyridones were synthesized by reaction of benzoylacetone and arendiazonium salt, followed by condensation with cyanoacetamide. Absorption spectra of all azo pyridone dyes were recorded in twelve protic and aprotic solvents in the range of 200-600 nm. A simple Hammett equation was used to study the effect of the substituents on the absorption spectra of these azo dyes. The solute-solvent interactions were clarified on the basis of linear solvation energy relationships concept proposed by Kamlet and Taft. The results showed that the solvent effects on the absorption spectra of the investigated azo dyes were very complex and strongly dependent on the nature of the substituents on the phenylazo group.