1, 10-phenanthroline derivative as colorimetric and ratiometric fluorescence probe for Zn2+ and Cd2+

A colorimetric and ratiometric fluorescent probe 2-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline (probe 1), was designed and synthesized for sensitive and selective detection of Zn2+ and Cd2+ ions in methanol, test paper and actual water samples. When probe 1 was excited at 350 nm in methanol solution, in the presence of alkali metal ions, alkali-earth metal ions and a variety of transition metal ions, it showed sensitive fluorescence selectivity to Zn2+ and Cd2+ ions. With the addition of Zn2+, the color of the solution changed from purple to cyan with the naked eye, and with the addition of Cd2+, the color of the solution changed from purple to blue. The fluorescence intensity of probe 1 showed a good linear relationship with Zn2+ and Cd2+ concentrations, and the detection limits were 0.04 mu M and 0.11 mu M, respectively. The binding mode of probe 1 and Cd2+ was dis-cussed according to the 1-Cd single X-ray crystal structure. In addition, the results of strip test and real water sample test showed that probe 1 has potential application in environmental metal ion recognition and detection.