Symmetry-breaking solvent effects on the electronic structure and spectra of a series of triphenylmethane dyes

The solution-phase properties of triphenylmethane (TPM), parafuchsin, crystal violet, ethylviolet, malachite green and Victoria Pure Blue are investigated via two-photon fluorescence emission and picosecond absorption spectroscopy. The torsional potential of TPM derivatives are also studied using quantum mechanical calculations. Overlapping visible absorption bands in parafuchsin, ethyl violet and crystal violet is the result of symmetry breaking. INDO calculations support a symmetry breaking due to the presence of a perturbing polar solvent molecule or counterion at the vicinity of one of the amino group positions.