Molecular heteroassociation in films of thiochrome and tryptophan

Optical absorption spectra were studied for films of tryptophan, thiochrome and their layer-by-layer composites. It was shown that the absorption spectra were rearranged in the composites. Quantum-chemical modeling of the electronic structure and optical transitions of the specified molecules, and their complexes, indicate that the reason for the rearrangement of the optical spectra is the heteroassociation between the molecules of thiochrome and tryptophan, which is accompanied by significant changes in the electronic states of the formed complexes.