A fluorescent pH probe for an aqueous solution composed of 7-hydroxycoumarin, Schiff base and phenanthro[9,10-d]imidazole moieties (PICO)

Abstract

The pH fluorescent probe 7-hydroxy-4-methyl-8-(((2-(1-phenyl-1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)imino)methyl)-2H-chromen-2-one (PICO) contains a donor-π-acceptor (D-π-A) conjugated system. The 'off-on' probe PICO has a pKa value of 8.01 and its fluorescence intensity is enhanced with increasing pH.