Photophysical properties of alloxazine derivatives with extended aromaticity - Potential redox-sensitive fluorescent probe.

The spectral and photophysical properties of two four-ring alloxazine derivatives, naphtho[2,3-g]pteridine-2,4(1H,3H)-dione (1a) and 1,3-dimethylnaphtho[2,3-g]pteridine-2,4(1H,3H)-dione, (1b) were studied. The propensity of 1a for excited-state proton transfer reactions in the presence of acetic acid as a catalyst was also studied, showing no signature of the reaction occurring. In addition, quenching of 1a fluorescence by acetic acid was investigated.