S-Block Metal-Oganic Coordination Polymer Materials:Syntheses, Structures, And Fluorescence Properties

The main objective of this thesis is to design and investigate novel crystalline fluorescence metal-organic coordination polymers （MOCPs）, which have been synthesized by employing s-block metal ions and rigid, flexible and mixed ligand with fluorescence property in hydrothermal （solvothermal） method. A series of novel and stable fluorescence MOCPs with active sites were obtained and characterized by single crystal X-ray diffractions analysis, fluorescence properties analysis, elemental analysis, powder X-ray diffraction analysis, fourier transform infred spectroscopy analysis, thermogravimetric analysis, gas sorption analysis, UV-Vis absorption spectra analysis. The space configurations, synthesis conditions and structure-properties relationship of s-MOCPs were discussed, and their fluorescence properties, sensor detection and fluorescence regulation were further studied. The main innovative work as follows:Sr²⁺/Ba²⁺ metal ions and rigid, blue-light emission ligand H₃BTPCA were were selected to assemble two novel fluorescence s-MOCPs:Sr（H₃BTPCA）（H₂O） （1） and Ba（H₃BTPCA）（DMF） （2） （DMF= N,N-dimethylformamide） under mild solvothermal condition. The active sites in s-MOCPs frameworks can interact with external metal ions to cause the change of their fluorescence properties, which can be used for sensing metal ions, and studied for modulating fluorescence color and white-light emission by introducing lanthanide metal ions. Fluorescence properties and the sensing mechanism of the two MOCPs were discussed deeply. The study provided a valuable reference for controllable synthesis of low-cost and potential fluorescent materials. Sr（H₃BTPCA）（H₂O） （1） Ba（H₃BTPCA）（DMF） （2）Based on our previous effort, alkaline earth metal ion Sr²⁺and flexible ligand H4ABTC was employed to synthesize stable sensing material:Sr（H₂ABTC）（DMF）（H₂O） （3）. And a homemade fluorescent sensor indicator-box was applied, when compound interact with amine gases, their fluorescence emissions can be significantly enhanced and red shifted, leading the fluorescence colors changed. The compound can recognize target gases with convenient, fast, undisturbed and repeatable fluorescence changes, and the sensing mechanism was studied, including closed loop effect and conjugation enhancement effect. The study has a promising application in biomedicine, food quality, environment monitoring and other fields. Sr（H₂ABTC）（DMF）（H₂O） （3）Nonluminous and low-cost Sr²⁺ and mixed ligands including H₂bqdc and phen were selected to construct a s-MOCPs with propeller molecular conformation:Sr （H₃BTPCA） （H₂O） （4）. The rare structure of compound 4 can avoid close π…π stacking effect, thus reduce the radiation energy loss, so that the fluorescence emission of compound 4 was significantly enhanced compared with separate ligand. Single crystal diffraction analysis showed that there were lewis base active site N atoms in the channel of the crystalline structure, leading good fluorescence properties of the compound 4 to detect organic pollutant 3-AT （amitrole） and toxic heavy metal ions Cd²⁺. Moreover,3-AT can be conveniently detected by an ultraviolet lamp and test strips, the heavy metal ion Cd²⁺can be recognized by fluorescence sensing with a low detection limit and good reusability, showing promising application of the sensing material. Sr （H₃BTPCA） （H₂O） （4）On the basis research of our group, nonluminous alkali metal ion Cs⁺and ligand H₃BTPCA were employed to obtain an ionic s-MOCP:（NH₄）₃[Cs₃（BTPCA）₂（DMF）₃] （5）, which was characterized by strong blue-light emission ligand and free NH4+ cations to make efforts on the developing of fluorescence emission regulation and white-light emission materials. Without multiple fabrication process, it showed clear color turning by postsynthesis via single ion exchange with green-light emission Tb³⁺ and red-light emission Eu³⁺, also, remarkable white-light emission property after dual ion exchange with Tb³⁺ and Eu³⁺ was realized. Furthermore, the white-light emission can be easier obtained by exchange single Eu³⁺ at a adjusted excitation wavelength. The feasible example of luminescence alkaline earth metal framework has provided a referable method for the rational design and synthesis of novel luminescence s-MOCPs to expand the range of luminescence functional materials. （NH₄）₃[Cs₃（BTPCA）₂（DMF）₃] （5）...