Proton- and metal cation-enhanced excited state intramolecular proton transfers of 2-(2-hydroxyfluorophenyl)benzoxazole having imidazole moiety

Protonation and ligation of a metal cation to the imidazole nitrogen atom of 2-(3,5,6-trifluoro-2-hydroxy-4-imidazolylphenyl)benzoxazole (1) enhance the green emission around 500 nm, which is ascribed to the ESIPT process.