Fluorescence sensor based on highly stable Cd(Zn)-coordination polymers for efficient detection of Cr2O72-/Nitrobenzene and recognition mechanism

Two new coordination polymers (CPs), namely, [Zn(GCA)(BDE)]·(H2O) (1) and [Cd(GCA)(TIB)]·(H2O) (2), were designed and synthesized by using H2GCA (Glutaric acid), TIB (1,3,5-tris(1-imidazolyl)benzene), BDE (1-(4-imidazole-1-ylphenyl)imidazole), with Zn2+ or Cd2+ ions under solvothermal or hydrothermal conditions. The two CPs were characterized via infrared spectroscopy, UV–vis spectroscopy, single-crystal diffraction, elemental analysis, thermogravimetric analysis, powder X-ray diffraction, and fluorescence properties. The 3D supramolecular compounds CPs 1–2 is formed by weak interaction hydrogen bonding or π … π stacking. Fluorescence detection results of CPs 1–2 show that they can act as excellent sensors of Cr2O72− and nitrobenzene with a low limit of detection, a high quenching rate and a high quenching constant. The results can be applied to the determination of Cr2O72− and nitrobenzene in water-ethanol system.