Highly selective and sensitive fluorescent probes for nitrofurazone and Hg2+ by two Zn (II)-based coordination polymers

The self-assembly of the pi-conjugated 1,4-di(1H-imidazol-1-yl)benzene (dib) and 4,4 '-di(1H-imidazol-1-yl)-1,1 '-biphenyl (dibp) ligands together with 4 '-(3,4- dicarboxylphenyloxy)-4-biphenylcarboxylic acid (H3L) reacts with metal Zn (II) salts to construct two new coordination polymers (CPs), namely [Zn (dib)(HL)(H2O)] (1) and [Zn (dibp)(HL)] (2). Fluorescence measurements reveal that 1 and 2 could display a highly sensitive fluorescence response toward Hg2+ and nitrofurazone (NFZ). Fluorescence investigations suggest that 1 and 2 are promising multi-responsive sensing materials for detecting Hg2+ and NFZ through fluorescence quenching (turn-off). The limits of detection toward Hg2+ ions are 0.221 mu M and 0.124 mu M, while the limits of detection toward NFZ are 0.757 mu M and 0.960 for 1 and 2, respectively. Interestingly, these Hg2+ and NFZ selective sensing processes can even be completed by the reusable CPs detected by the naked eyes. Hirshfeld surfaces and fingerprint plots are extensively used to investigate intermolecular interactions, which play a crucial role in creating diverse supramolecular designs that can be compared.