The optical properties of triphenylmethane dye molecules and chromogens

Industrial dye monomers, including malachite green, crystal violet, brilliant green, and methyl violet, were isolated by extraction with the use of heptane. UV light absorption bands characteristic of pure molecules were determined. The molecules of the dyes studied, which were ion pairs (formed by dye cations and oxalate or chlorine anions), did not absorb light in the visible range; that is, they were not chromogens. The conclusion was drawn that chromogen particles responsible for chromaticity were supramolecular dimers of nonchromogenic triphenylmethane series molecules. This conclusion was substantiated by trends in spectral transformations with the participation of immonium hydroxides obtained from dyes and side products of the synthesis of industrial dyes with quinoid molecular structures.