Synthesis,Structures And Properties Of Transition Metal Coordination Polymers Derived From Bisimidazolyl Benzothiadiazole Ligands

Porous coordination polymers are widely used in the fields of fluorescence,catalysis,adsorption,magnetism,and nonlinear optics because of their novel and variable topological structure and different size channels,which has opened a new direction for the research of inorganic material chemistry and attracted much attention from chemical researchers.In this thesis,2,1,3-benzothiadiazole?BTD?with the rigid?-conjugated structure is used as the primitive to synthesize a novel organic fluorescent ligand 4,7-bis?1H-imidazol-1-yl?-2,1,3-benzothiadiazole?BIBT?.On this basis,eleven new transition metal coordination polymers with different dimensional structures were successfully constructed.X-ray single-crystal diffraction,infrared spectroscopy,and X-ray powder diffraction were used to characterize the structures of transition coordination polymers.The fluorescence and magnetic properties of the partial coordination polymers were studied.In addition,general rules of the construction of related materials and the regulation of structures and properties were summarized.The main contents are summarized as follows:1.Based on the organic fluorescent ligand BIBT,three V-shape aromatic carboxylate ligands,and Zn?II?,Cd?II?and Co?II?salts,six new transition metal coordination polymers have been constructed.Their crystal structure as well as fluorescence and magnetic properties were studied in detail.Fluorescence measurements show that the ligand BIBT has a fluorescence quenching effect on Cu²⁺,and coordination polymer 4 could have fluorescence quenching effects on Fe³⁺,Cr³⁺and Al³⁺simultaneously with high selectivity and sensitivity,strong anti-interference,and low detection limit.Thus,4 can be used as a multifunctional fluorescence sensing material for Fe³⁺,Cr³⁺and Al³⁺.Magnetic investigation suggests that weak ferromagnetic and antiferromagnetic couplings between the adjacent Co^IIions in the Co₂ clusters exist in 3 and 6.2.By using rigid auxiliary ligands such as 5-hydroxyisophthalic acid?H₂HIPA?,5-nitroisophthalic acid?H₂NIPA?and 1,3,5-benzenetricarboxylic acid?H₃BTC?,five porous coordination polymers were successfully constructed via adjusting the ratio of reaction raw material under the same solvent conditions.The results of the fluorescence property study indicate that coordination polymer 10 could simultaneously sense Fe³⁺,Cr³⁺and Al³⁺ions through the fluorescence enhancement effect with high selectivity and sensitivity,which is the first turn-on MOF fluorescent sensor for Fe³⁺,Cr³⁺,and Al³⁺simultaneously.Coordination polymer 11 senses the solvent acetylacetone through red fluorescence shift.