A near-infrared phosphorescent iridium(iii) complex for fast and selective detection of phosgene

Abstract

Phosgene, a colorless and highly toxic gas, serves as a critical raw material in various industrial production processes. Its accidental leakage poses a significant risk to public safety. Therefore, developing a method for the rapid and sensitive monitoring of phosgene is of considerable practical significance. A ‘‘turn-off’’ near-infrared iridium(III) complex phosphorescent probe FNO3 was synthesized for real-time luminescence detection of phosgene. After reacting with phosgene, the oxime groups in FNO3 were converted to cyanide groups, resulting in the formation of a weaker luminescent product, FNO3-CN. The results of emission titration spectroscopy tests demonstrated a strong linear relationship between the logarithm of the emission intensity of FNO3 and the concentration of phosgene. The detection limit was as low as 0.18 μM, indicating that FNO3 is capable of quantitatively detecting low-concentration phosgene (as low as 4 ppm). Probe FNO3 exhibited high sensitivity, rapid response (<5 s) and good selectivity towards phosgene. Finally, test strips were prepared by immobilizing FNO3 on filter paper and were successfully applied for the colorimetric detection of phosgene.