An Efficient Probe of Cyclometallated Phosphorescent Iridium Complex for Selective Detection of Cyanide

A cyclometallated phosphorescent iridium-based probe to detect CN- was prepared through a cyanide alcoholize reaction based on the C^N type main ligand and N^N type ancillary ligand (2-phenyl pyridine and 1,10-phenanthroline-5-carboxaldehyde, respectively). The efficient probe exhibited good sensitivity in response to CN- in an CH3CN and H2O (95/5) mixture within a 1.23 μM detection limit. The response of PL is directly in line with the concentration of CN- from 0 to 2.0 equiv. The PL investigation of other reactive anions proved the great selectivity to CN-. Additionally, upon adding 1.0 equiv. of cyanide, the formation of cyanohydrin was correctly elucidated in 1H NMR, FT-IR, and mass spectra studies. The conspicuous results indicate that the iridium complex has the potential possibility of application in other biosystems related to CN-.