Metal-/carboxylate-directed four d10 piperazine-amide-based coordination polymers for the fluorescent detection of nitrophenol and nitroaniline in various water environments

Four piperazine-amide-bridged d10 metal-organic coordination polymers, namely, [Zn(L)0.5(1,3-BDC)center dot H2O]center dot H2O (1), [Cd(L)(1,3-BDC)] (2), [Zn(L)0.5(5-MIP) center dot H2O]& sdot;H2O (3), [Cd(L)(5-MIP)] (4) were synthesized by the L ligand [N, N'-bis[(3-pyridin)acrylophenone] piperazine (L)] and two carboxylic acids with Zn/Cd(II) chloride under hydrothermal conditions. The title complexes were characterized by IR spectroscopy, powder X-ray diffraction and single-crystal X-ray diffraction. Complex 1 is a 1D ladder-like structure. Complex 2 is a 3D NaCl type framework. Complexes 3 and 4 are 63 and 44 connected 2D structures. The different structural details of the title complexes directed by caroxylates and the central metals were compared. The complexes 1-4 can be used as excellent fluorescent sensors toward nitrophenol (NOP) and nitroaniline (NA) with a low limit of detection and a high quenching constant, and have good anti-interference and recyclable characteristics. The feasibility of actual sample detection was verified by tap water, river water and wastewater samples. Taking complex 3 as an example, the mechanism was also explored by fluorescence lifetime experiment and the UV-visible absorption spectroscopy. The 3-modified visual detection cloth and test paper were also prepared by solid phase deposition method.