Electronic and Optical Properties of Reactive Orange 16 azo dye

Azo dyes constitute the largest family of synthetic dyes. They are widely used in the textile, dye stuff and pharmaceutical industries. The uncontrolled and undesirable discharge of the azo dyes into the environment may represent a serious ecological problems and health effects. The oxidation of azo dyes (e.g., Photo-oxidation, Oxidation by ozone) leads to its degradation. To determine the reactivity and the active sites of azo dye reactive Orange 16 (RO16), the authors calculated its electronic and optical properties by using DFT and TD-DFT methods at B3LYP/6-311+G(,p) level in solvent (IEF-PCM model). The results showed that RO16 is polar and high soluble compounds in water. The Fukui indices showed that the N11 is the favoured site of nucleophilic attack (e.g., ozone). A good correlation was obtained between the predicted and experimental absorption bands of RO16 (R2=97%).