PHOTOTAUTOMERISM OF BETA-CARBOLINE

In this work, we study proton transfer spectroscopy properties of beta-carboline (norharman) chloromethanes/acetic acid mixtures. Solvents used were dichloromethane, chloroform, and carbon tetrachloride. The triple fluorescence from the neutral form and the double fluorescence from the cationic form can be rationalized by systems containing three and two species, respectively, which are kinetically coupled in the excited state S-1. However, this complex system is only observed in chloromethanes/acetic acid mixtures; in chloromethane or acetic acid, only neutral and cationic forms emit, respectively. The complex fluorescence dynamic shown in this work had not been observed previously.