Photophysical Responses of Benzimidazolic and Benzoxazolic HydroxyCoumarin Dyes

We synthesized four novel benzoxazolic and benzimidazolic derivatives of 6-hydroxycoumarin and their photophysical properties were studied. The products with brilliant yellow color shades declared green fluorescence. The emission peaks of the products appeared 456–474 nm. The important characteristic for fluorescent compounds, the Stokes shift νA-νF, oscillator strength f, and fluorescence quantum yield ΦF were measured. Furthermore, their photophysical and electronic properties have been investigated at the theoretical level using density functional theory. Dyeing of nylon fabrics was carried out by the synthesized fluorescent dyes as well. They generally flatten off at dye concentrations of 2-3 owf.