THE DIFFERENT RECOGNITION MECHANISM OF CARBAZOLE DERIVATIVES FOR BIOLOGICAL IMPORTANT ANION: THEORY AND EXPERIMENT

Two fluorescent anion sensors bearing phenol, carbazole-NH and -NO2 group were designed and synthesized. They both exhibited highly binding ability for H2PO4- among the anions tested. In the presence of H2PO4-, the fluorescence of the sensors underwent a dramatic enhancement, while the presence of other anions such as F-, AcO-, Cl-, Br-, and I-, had weak or no effect on the fluorescence. The determination limit of two sensors (1 and 2) toward H2PO4- were 3.0x10-7 and 5.0x10-7 molˑL-1, respectively. Theoretical investigation indicated it was the highest HOMO to induce the red-shift phenomena of two sensors.