An ab initio study of the absorption spectra of indirubin, isoindigo, and related derivatives

The UV/visible spectra of a series of indirubin, isoindigo, and other indigo/thioindigo related dyes are evaluated in various solvent environments by using the time-dependent density functional theory in conjunction with the polarizable continuum model. It is stated that even for molecules of the same family, significant differences in the excitation processes are noted.