Quantitative evaluation of solvation and packing effects on the visible absorption of anthraquinone derivatives

The solvatochromism of five anthraquinone compounds was evaluated at the TD-B3LYP level using the 6-31G(d,p) basis set whilst packing effects were investigated via an approach that combined semi-empirical and ab initio methods, namely ZINDO/TD-B3LYP/6-31G(d,p). This enabled calculation of the colourant's λmax with an average accuracy of 0.14 eV. The packing effects induced large changes in the UV/VIS spectra of the anthraquinones; large bathochromic and hyperchromic displacements were observed.