Nerve Agent and Pesticide Deactivation with Group 13 Chelates

Binuclear boron halide compounds of the type L[BX₂]₂ (L= Salen(tBu) ligands, X= Cl, Br) can dealkylate a wide range of organophosphate compounds with high conversion at room temperature. Mononuclear boron Schiff base compounds of the type LBX (L= Salen ligands, X=Br, Cl) (Inorg. Chem. 45 (2006) 9213) and aluminum Schiff base compounds of the type Salen(^tBu)AlBr (J. Am. Chem. Soc. 128 (2006) 1147) can also dealkylate organophosphates. In these reactions the resulting product is a compound where the dealkylated phosphate ester is covalently bonded to the group 13 element through a hydrolytically stable M-O-P linkage. Recently, the U.S. Army Edgewood Chemical and Biological Center has demonstrated the dealkylation of actual nerve agents and pesticides with these compounds (New J. Chem. 32 (2008) 783). Thus, the dealkylation reaction may be used to deactivate nerve agents in bulk or decontaminate objects exposed to such agents in the field. The resulting byproducts would be non-toxic, stable solids that could be left in situ or disposed of through routine handing. Studies are in progress to determine whether the dealkylation of phosphate esters can be conducted in the gas phase, opening the possibility of using the group 13 reagents in gas mask filters and airborne nerve agent sensors.