Multifunctional Fluorescent Probes for Chemical Warfare Agents Phosgene and Sarin Simulant: Heteroatom...

Multifunctional fluorescent probes targeting chemical warfare agents have been highly valued due to high-detection efficiency and cost-effectiveness, but sluggish development and inadequate performance remain imminent. Exploiting innovative design strategies is the most effective program to achieve performance breakthroughs. Here, we propose heteroatom engineering, substituting the sulfur (S) atom with the strongly electron-donating nitrogen (N) atom, and develop the multifunctional fluorescent probes MeBIMPCz and MeBIM3PCz targeting phosgene and diethyl chlorophosphate (DCP, the mimic of Sarin). Computational calculations reveal that the heteroatom substitution markedly decreases the electrostatic potential (ESP) and average localized ionization energy (ALIE), enabling substantial boosting of the reactivity. Hereby, the probes enable highly sensitive detection of phosgene and DCP up to nanomolar-liquid/ppm-vapor (LODs: 1.95 nM-liquid/0.24 ppm-vapor for phosgene; 28.71 nM-liquid/25.54 ppb-vapor for DCP). And the limit of detection for DCP is improved by up to two orders of magnitude, and the response time for phosgene is shortened fourfold (from 20 min to 5 min), with superior specificity and anti-interference performance. Furthermore, the test strips integrated with a smartphone not only fulfill qualitative and semi-quantitative detection but also perform well in multiple realistic scenario simulations (accidental leakage during industrial accidents, hazardous residue from terrorist attacks and chemical screening in security inspections) and long-term monitoring assays (up to 15 days). This work provides a promising molecule design strategy to realize multifunctional probes through heteroatom engineering.