Strategic Design of Anthracene-Decorated Highly Luminescent Coordination Polymers for Selective and Rapid Detection of TNP: An Explosive Nitro Derivative and Mutagenic Pollutant

Explosive nitroaromatic compounds (epNACs) are a class of molecules responsible for massive loss of life in the form of terror attacks and health hazards. Discerning detection of 2,4,6-trinitrophenol (TNP) like mutagenic pollutant and epNACs using robust luminescent coordination polymers (CPs) has been always a potential research field for the sake of environmental health and homeland security. In this regard, one-dimensional (1D) CPs, {[Zn(adc)(avp)2(H2O)]·(H2O)3}n (1) and {[Cd(adc)(avp)2(H2O)]·(H2O)·(CH3OH)}n (2) {H2adc = acetylenedicarboxylic acid and avp = 4-[2-(9-anthryl)vinyl]pyridine} have been synthesized using H2adc and avp ligands into aqueous solution of the nitrate salts of corresponding metal ion. Both of the polymeric compounds show extensive hydrogen bonding and π···π stacking interactions to form three-dimensional (3D) structures. The presence of geometrically suitable proximal anthracene moieties (extended π-conjugation) in both the compounds provides feasible interacting sites for incoming analytes that also explains their prompt sensing property. Interestingly, both the fluorescent sensing probes exhibit highly efficient ratiometric and selective sensing ability toward TNP with fast response over other comparative epNACs. A detailed investigation on the mechanistic pathways for the quenching response has been obtained by density functional theory calculation. The results show higher sensitivity of 2 with a limit of detection (LOD) of 0.45 μM as compared to 1 (LOD ∼ 0.51 μM). To the best of our knowledge, such hitherto unknown CPs acting as highly fluorescent sensors are not known in the literature. Here, strategically decorated anthracene moieties are congenial to geometrically accessible interacting sites for rapid and selective detection of an explosive nitro derivative as well as mutagenic pollutant TNP with higher sensitivity.