Synthesis, Crystal Structure And Properties Of Multifunctional Metal-organic Framework Materials Based On Nitrogen-rich Organic Ligand

Coordination polymers（CPs）are composed of metal ions,clusters,and org anic linkers.These are widely used in the fields of adsorption,separation,drug delivery,sensing,luminescence,capacitors and catalysis.In this paper,4,5-di（1H-tetrazol-5-yl）-2H-1,2,3-triazole（H₂L）nitrogen-rich organic compounds as ligands,with various inorganic metal salts as metal centers,we synthesized a variety of coordination polymers.After detecting their essential characteristics,their respective applications in various directions were studied.The basic content and results of the research are summarized as follows:（1）A novel compound based on the N-rich ligand-{[Cu L（H₂O）]·H₂O}_nwas successfully synthesized by a simple solvent thermal reaction.Compound 1 displays a three-dimensional supramolecular structure constructed from the two-dimensional layers,and has been further characterized by powder X-ray diffraction,elemental analysis,and thermogravimetric analysis.The electrochemical properties of compound 1 have been studied in detail.On the one hand,the GCE modified by compound 1 can be effectively used to simultaneously detect the two heavy-metal ions Cd²⁺and Pb²⁺.The LODs are 15 n M for Pb²⁺and 0.16μM for Cd²⁺.On the other hand,compound 1,as an anode material for LIBs,shows excellent reversible capacity,cycle stability,and rate performance.（2）Two Pb（II）coordination polymers based on nitrogen-rich organic ligands were synthesized at different solvents and temperatures:compound 2（{[Pb（HL）（H₂O）]·I}_n）and compound 3（{[Pb（HL）（H₂O）]·Br}_n）.The crystal structures of these two compounds are similar but slightly different,the same is that they belong to the same crystal system and group,and are both three-dimensional supramolecular structure connected by C-H···πinteraction;the difference is that their contents of free anions are different,and the differences may mainly come from their different reaction conditions.The test results of the luminescence study show that compounds 2and compound 3 have a broadband yellow light emission behavior,and that their photoluminescence is tunable,and their broadband luminescence characteristics have applicable potential in using them as yellow phosphors to make white light devices.（3）Select similar infinite metal salts with the same cation to synthesize a new coordination polymer compound 4（{[Pb（HL）₂（H₂O）₂]·H₂O}_n）under hydrothermal conditions.Compound 4 is a three-dimensional supramolecular structure formed through C-H···πinteraction after expanding into the plane to form a network.The luminescence performance of compound 4 was characterized by FT-IR spectroscopy and UV-Vis spectrogram.Experiments and data illustrate that compound 4 has blue light emission properties caused by electron transitions of nitrogen-rich organic ligand,and this work provides a new idea for studying the luminescence properties of novel complexes based on nitrogen-rich organic ligand.（4）The nitrogen-rich organic ligand H₂L synthesizes a colorless coordination compound 5（{[Zn HL]·DMA}_n）,after basic characterization by powder x-ray diffraction and SEM,explored the associated fluorescence-sensing properties of compound 5.Fluorescence sensing experiments showed that compound 5 can rapidly and sensitively detect Cr₂O₇^2-anions by fluorescence quenching effects,with a detection limit of 0.81μM.Besides,compound 5 still has excellent anti-interference ability in the presence of various interfering anions.