Synthesis, spectroscopic characteristics, dyeing performance and TD-DFT study of quinolone based red emitting acid azo dyes

Eight novel fluorescent heterocyclic acid dyes were prepared by diazotizing various sulphonic acid based amines and coupling with 4-hyrdoxyl-1-methyl-2(1H)-quinolone. Structures of synthesized dyes were well supported by 1H NMR, 13C NMR, Mass spectroscopy, FTIR and elemental analysis. The effect of high molecular weight and heterocyclic moiety were observed to have significant influence on photophysical properties, color values and fastness performances of the dyes. Substitutions on ortho to azo linkage played an important role in enhancing light and wash fastness properties of the dyes. Dyeing characteristics of all the dyes were evaluated on wool, nylon and silk substrates. Evaluation of UV-protection factor (UPF) of the dyed fabrics suggested that these dyes can be used to make UV-protective fabric. DFT calculations were employed to calculate the stability of tautomeric forms of the dyes and find out electrophilicity index of prepared dyes. TD-DFT used to study structural effect on photophysical properties.