A phosphorescent Ir(III) complex with formamide for the luminescence determination of low-level water content in organic solvents

A phosphorescent water probe based on an Ir(III) complex with 5-formamide-1,10-phenanthroline as an N^N ligand has been designed and synthesized. Its phosphorescence emission can be quenched by the addition of a fluoride anion through a deprotonation process occurring in –NH and it can be recovered by adding a trace amount of water to the detecting solution. Based on this performance, the phosphorescent probe has been utilized to determine the water content in organic solvents, which shows low limit of detection (LOD) and limit of quantitation (LOQ). Furthermore, taking advantage of the long emission lifetime of the phosphorescence signal, a time-resolved photoluminescence experiment was performed for detecting the water content, which could effectively eliminate the fluorescence background and improve the sensitivity and the signal-to-noise ratio of detection in complex systems.