Solvatochromism and preferential solvation of 2,6-dichloro-4-nitroaniline in pure and binary aqueous mixtures

In this study, the solvatochromic behavior of 2,6-dichloro para-nitroaniline (DCPNA) was investigated in a wide range of pure solvents, and binary solvent mixtures of water with ethanol, dimethyl sulfoxide, and dimethyl formamide at 298.15 K. The absorption spectrum of DCPNA in the ultraviolet–visible range exhibits a characteristic peak that shifts with changes in the solvent along the absorption wavelength. The influential factors and their roles in solvatochromism were determined through KAT-LSER analysis in pure solvents. Solvatochromism in binary solvent mixtures showed a completely non-linear trend with respect to the composition of the solution. The recently introduced preferential solvation model was utilized to model the absorbed light wavenumber in aqueous solvent mixtures. This model elucidates the separate effects of preferential solvation of DCPNA and the non-ideal behavior of aqueous solvent mixtures in the non-linearity of solvatochromism.