The Properties And Applications Of Functionalized Metal-organic Frameworks

Metal-organic frameworks(MOFs)are compounds consisting of metal ions or clusters coordinated to organic ligands to form network skeletons,and they have been extensively studied because of their potential applications in gas adsorption,separation,catalysis,detection and magnetism.MOFs have a wide variety of structures.In recent years,the flexible MOFs and the luminescent properties of MOFs have been received considerable attention.In this thesis,the work is mainly focused on these two aspects.On the basis of structural design,the flexible MOFs were sythesized under hydrothermal condition.The crystal structures of these compounds were determined by single crystal X-ray diffraction.These compounds were further characterized by powder X-ray diffraction,IR spectroscopy and thermogravimetric analysis.The conversion process between the flexibility and rigidity of MOFs were investigated.In the meantime,the continuous process of photon energy transfer in supramolecular structure of MOFs was also be researched.In the first chapter,the research development was introduced briefly.The significance and main work content of this thesis were also introduced in this chapter.In the second chapter,the phase transition process of MOFs was regulated by structural design.Meanwhile,the rigid and flexible properties of the structure were controlled by means of hydrogen bonds.Under the research and analysis of the flexible skeleton,the MOFs which were reversible in the three discontinuous states were obtained.Most noteworthy is that the pore size of the flexible MOFs can be adjusted initiatively through changing solvent environment,and dye with tiny difference in the size can be adsorbed step by step.In the third chapter,the downconversion(DC)process was introduced into MOFs by doping rare earth metal ions to achieve the synergy of DC and down-shifting(DS)procedures.The results showed that the narrow absorption spectra and low absorption intensity were effectively improved through the DS process.The luminous efficiency of the materials was increased under the DC process.In the fourth chapter,the main achievements of this thesis were summarized.The future research on MOFs has also been proposed.