| Metal-organic coordination polymers(MOFs or CPs)are a kind of inorganic-organic hybrid materials,which formed by self-assembly of metal centers and organic ligands through various coordination modes.Owing to their diverse components,novel structures and intriguing topologies,recently MOFs or CPs exhibit great potential applications in many fields,such as guest molecule adsorption and separation,photo-luminescence,catalysis,sensing,and biomedicine.Compared with other common neutral materials,frameworks with intrinsic charge properties exhibit special properties that arise from their extra charge sites.However,such reports are still rare.Considering this situation,a series of coordination polymers based on zwitterionic ligands and transition metals have been designed and successfully synthesized.These frameworks all possess charged skeletons,and their structures have been fully characterized,including single crystal X-ray diffraction analysis,X-ray powder diffraction analysis,elemental analysis,etc.Meanwhile,according to the different structures,their fluorescence performance,gas adsorption and separation performance,organic dye adsorption and separation performance have been explored,respectively.And the relationships between particular charge sites and properties have been studied in detail.This paper mainly includes the following aspects:In Chapter 1,the development of the metal-organic coordination polymers is reviewed.The design,synthesis and characterization methods,as well as the applications of coordination polymers are also introduced.The development of ionic-type frameworks is reviewed in detail.In Chapter 2,a series of ionic-type ligands have been synthesized.And then several coordination polymers with same coordination mode were obtained by solvothermal method.All of them have a one-dimensional chain structure and form the three-dimensional(3D)supra-molecular polymer through inter-chain interactions.The luminous properties of complexes in this chapter have been fully studied.Due to the coordination interactions of zwitterionic ligands with metal centers,the charge transfer obtains more channels,which could extend luminous lifetime.Compared with ligands,all the above complexes feature fluorescent and phosphorescent properties simultaneously in room temperature.Among them,since unique structure,one complex presents tunable color,which can be regulated by wavelength and temperature directly.The calculation results indicate that the electron transfer process involved MLCT and LCCT.We hope this study could provide assistance for designing related luminescent materials.In Chapter 3,by solvothermal method,coordination polymers based on ionic-type ligands were synthesized.This series of complexes also have the one-dimensional chain structure,and then formed three-dimensional frame through hydrogen bonding and ?…? interactions.By adjusting the position of the positively charged N+sites,the gas adsorption performance has changed significantly.Moreover,due to the charge-induced interaction between the framework and the guest molecules,the adsorbed gas molecules are very difficult to desorb,and the heats of adsorption are also significantly increased.By X-ray single crystal diffraction analyses,we also confirmed the gas adsorption sites.The results proved that the adsorption sites are very close to the charge sites.Therefore the charge sites play an important role in adjusting the gas adsorption performance.Taking advantage of the different affinity for different polarized gases,the breakthrough experiments were also carried out.The complex exhibits selectivity of mixture gases.Calculation results also proved that charged sites have a significant effect on adjusting gas adsorption sites.In the last chapter,we summarize the work of this paper and forecast the relevant directions. |
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