Fabrication of 5-R-isophthalic acid-modulated cadmium-organic coordination polymers and selectivity for the efficient detection of multiple analytes

Excessive emission of inorganic ions and organic molecules can pose a potential threat to human health and the environment. Therefore, finding a way to detect contaminants is crucial. Coordination polymers (CPs) are of great practical importance as effective chemical sensors. Secondary auxiliary ligands with different functional groups were synthesized (by a hydrothermal method) and characterized: {[Cd-2(3-dpyp)(1,3-BDC)(2)]H2O}(n) (1), {[Cd(3-dpyp)(0.5)(1,3-BDC)(H2O)(2)]H2O}(n) (2), {[Cd-2(3-dpyp)(5-MIP)(2)(H2O)(3)]2H(2)O}(n) (3) and {[Cd(3-dpyp)(5-HIP)]1.5H(2)O}(n) (4), where 3-dpyp = N,N '-di(3-pyridinecarboxamide)-1,3-propane, 1,3-H2BDC = 1,3-benzenedicarboxylic acid, 5-H2MIP = 5-methylisophthalic acid and 5-H2HIP = 5-hydroxyisophthalic acid. Single-crystal X-ray diffraction (SCXRD) analysis showed that the four Cd-CPs exhibited fascinating two/three-dimensional structures. Moreover, Cd-CP-1-4 showed excellent stability in the pH range of 1-14 and in different organic solvents. Powder X-ray diffraction analysis and thermogravimetric analysis indicated that the Cd-CPs possessed high chemical and thermal stabilities. Furthermore, with the aim of "using waste to treat waste", fluorescence properties showed that Cd-CP-1-4 could be used as multi-response sensors for Fe3+, MnO4- and nitrobenzene with high sensitivity, selectivity and efficiency.