Cobalt complexes of Biginelli derivatives as fluorescent probes for selective estimation and degradation of organophosphates in aqueous medium.

The unregulated use of organophosphates (OPs) as pesticides and toxic chemical warfare agents demands their continuous monitoring from a human health perspective. This study describes a fluorescence turn-on sensing assay for the selective quantification of OPs in aqueous medium. Metal complexes of two different Biginelli derivatives were processed in water through a reprecipitation technique. The engineered self-assembly of the pyridyl-2-cobalt complex (L1·Co(II)) was employed to selectively detect malathion while the pyridyl-4-cobalt complex (L2·Co(II)) could estimate azamethiphos fluorimetrically up to a detection limit of 9.2 nM and 11 nM, respectively. Furthermore, the pesticide degradation ability of OPs was assessed using a 31P-NMR technique. This new paradigm expands the versatility of Biginelli derivatives as promising sensing platforms via metal complexation which may further be explored for estimation of analytes.