Phosphorus-containing nerve gases

    Development of nerve gases during the latter half of the twentieth century became coupled not just with their actual use, but with the threat of potential use during war. Two examples are Sarin and Soman, which function by enzyme inhibition in the nervous system; inhalation of ≈1mg is fatal.

Policies of many countries are now for chemical weapon disarmament, and programmes for the destruction of stockpiled nerve gases have been enforced. A problem for those involved in developing destruction processes is to ensure that end-products are harmless. Sarin, for example, may be destroyed by hydrolysis:

and the use of aqueous NaOH results in the formation of effectively harmless sodium salts. Rapid detection of chemical warfare agents is essential.

   One method that has been investigated makes use of the release of HF from the hydrolysis of the fluorophosphonate agent. The reaction is catalysed by a Cu(II) complex containing the Me₂NCH₂CH₂NMe₂ ligand:

    The reaction is carried out over a thin film of porous silicon (which contains the Cu(II) catalyst), the surface of which has been oxidized. As HF is produced from the hydrolysis of the fluorophosphonate, it reacts with the surface SiO₂, producing gaseous SiF₄:

   Porous silicon is luminescent, and the above reaction results in changes in the emission spectrum of the porous silicon and provides a method of detecting the R₂P(O)F agent.