Fluorescence behavior of chromones containing several protolytic centers 3-Thiazolylchromones: Emission band assignment and pH dependent effects.

Fluorescence properties of 3-thiazolylchromones (TC) were studied in the wide H(0)/pH range -10 to 12. It was found that the number of the excited TC protolytic forms exceeds their quantity in the ground state. The formation of the new emitting species was explained as the result of the dramatic changes in the acid-base characteristics of three protolytic centers of TC molecules under the electronic excitation.