Colorimetric Sensor for Detection of Tabun Mimic Diethyl Cyanophosphonate

Herein, a colorimetric chemosensor (probe 7) was designed and synthesized for sensing diethyl cyanophosphonate (DCNP), a Tabun nerve agent simulant. The sensitive, selective, fast response and photostable probe 7 in dimethylsulfoxide (DMSO) responded to DCNP at low concentrations with visual naked eye color change from pink to pale yellow and displayed unresponsive behaviour against various interferences except for copper ions, which can be differentiated by adding ethylene diamine where the yellow color persisted in the case of DCNP but turned to pink in the case of copper ions. Additionally, the yellow aqueous solution of probe 7 at pH 10 and 12 turned colorless against the response of DCNP. The limit of detection (LOD) of probe 7 was found to be 50 nmol/L in an aqueous basic solution at pH 10 for the detection of DCNP. The formation of the cyclized product was elucidated by ¹H and ³¹P NMR nuclear magnetic resonance (¹H NMR, ³¹P NMR), Fourier transform infrared spectroscopy (FTIR), and high-resolution mass spectrometry (HRMS) analysis. The filter paper and silica plate loaded with probe 7 were fabricated for real-time and on-site detection of DCNP.