Photolysis and quantum-chemical calculations of the nalidixic acid radical states

The nalidixic acid transient spectra were analyzed and the scheme of photo-conversion of the acid was suggested. At a large delay of laser pulses the transient absorption spectra contain the bands due to the dissociation of the products of the cation- and anion-radical photodecomposition in the micro- and millisecond range. By quantum-chemical calculations we revealed that at the transition to the ion-radical state a proton migration occurs subsequent to the movement of the center of gravity of the negative charge. The phototransformation of nalidixic was found to proceed with a TICT-effect.