Selective Detection of Nerve Agent Simulants by Using Triarylmethanol-Based Chromogenic Chemodosimeters

A family of triarylcarbinols 111 has been synthesised, and the chromogenic behaviour of the members in the presence of nerve-agent simulants diethylcyanophosphonate (DCNP) and diisopropylfluorophosphate (DFP) in acetonitrile and in buffered mixed water/acetonitrile solutions has been investigated. Hydrophobic polyethylene oxide films of these compounds have been prepared. Some of these triarylcarbinols act as OFF/ON chemodosimeters for the nerve agent simulants. The sensing mechanism includes phosphorylation of the hydroxyl group in the triarylcarbinol derivatives, followed by a dephosphatation reaction induced by the electron-donor groups present in the structure. The existence of additional tert-butyldimethylsilyl ether groups in compounds 2 and 3 permits these reagents to act as double probes by allowing selective signalling of DFP. The reactivity between 1 and 46 with DFP and DCNP in acetonitrile or water/acetonitrile solutions under pseudo first-order kinetic conditions was studied to determine rate constants (k) and the half-life times (t1/2) for the corresponding reactions. Films containing compound 2 were used to detect simulants both in solution and in the vapour phase. Finally, a logic device was designed that incorporated compounds 2, 14, and 15 that allowed detection of DFP (a Sarin and Soman simulant) and DCNP (a Tabun simulant), even in the presence of possible interferents such as acids.