Degradation by hydrolysis of three triphenylmethane dyes: DFT and TD-DFT study

Abstract

DFT reactivity descriptors, the ultraviolet-visible spectra and hydrolysis mechanism of three cationic dyes (Malachite Green (MG), Brilliant Green (BG) and Ethyl Green (EG)) are performed with several exchange-correlation functional (global GGA, hybrids and rangeseparated). Using time-dependent density functional theory the theoretical ultravioletvisible absorption spectra of the three cationic dyes are obtained and obey the trend for the λ max : GGA > hybrid > range-separated functional. Thanks to the transition state theory, the barriers of hydrolysis mechanism of the cation structures dyes were obtained in gas and solution phase. It is shown that, for these systems the barriers are in order: BG + < MG + < EG 2+ in gas and solution phase. In the two phases, the CAM-B3LYP functional gives the highest barriers and the M06 gives the lowest ones.