Light Fast Monoazo Dyes with an Inbuilt Photostabilizing Unit: Synthesis and Computational Studies

A series of monoazo disperse dyes with a photostablilizing o-hydroxycarbonyl moiety was incorporated resulted in the enhancement of the light fastness properties on polyester and nylon substrates as compared to the dyes that do not possess the photostablilizing moiety. The geometries of the azo and the hydrazone tautomeric forms of all dyes were optimized at B3LYP/6-311+G(d) and electrophilicity index was calculated for propensity of the moiety to absorb electrons. The values of absorption and stability trend of the dyes were in good agreement with the trend of experimental light fastness values. These disperse dyes possess excellent wash fastness and moderate to good sublimation fastness on hydrophobic substrates.