Enantiopure chiroptical probes for circular dichroism and absorbance based detection of nerve gas simulants

Abstract

A series of oxovanadium(V) compounds 1–4 were prepared and explored as stereodynamic chiroptical probes to detect a simulant of sarin known as diethyl chlorophosphate (DCP) without any interference from the competing analytes. Simultaneous CD cum UV/vis based bimodal instant recognition of DCP using optically active probes is unprecedented. Upon fabricating the vanadium compound with a polymer has yielded a chiroptical membrane, which showed a change in its dichroic as well as colorimetric signals on interaction with DCP vapour at 1 ppm. EPR and UV/vis studies revealed an irreversible change of the CD-active V(V) to the CD-silent ternary V(V) species in presence of DCP via a transient V(IV) species. Nucleophilic attack of the alkoxo oxygen of 1–4 to the electrophilic P atom of DCP resulted in the formation of ternary V(V) compounds as confirmed by ⁵¹V/³¹P NMR.