Synthesis Of MOFs Materials With Azobenzene Derivatives As Switches And Their Reversible Adsorption Study

Metal-Organic Frameworks?MOFs? material selectively adsorp gas, can be potentially used in gas storage and separation. MOFs are a type of promising adsorbents in applications of gas separation and purification due to their high surface area and large accessible pore volume. In particular, they have been considered as sorbents for gas capture. In a practical application, MOFs show many advantages to act as gas adsorbent, but show many advantages to which are in face of many problems and challenges.Azobenzene derivatives with light isomerization characteristics, makes the azobenzene and its derivatives become a kind of very important photoelectronic materials. Under the condition of illumination, azobenzene derivatives make the transition form a stable plane trans structure into a three-dimensional structure of cis,in another wavelength of light or heating conditions, azobenzene derivatives by cis structure back to trans isomerization. Base on this photoinduced change in molecular shape, azobenzenes find many practical applications in MOFs as optical switch.In this paper, three kind of azobenzene derivatives are chosen as optical switch,which include 2, 5- dicarboxyl-4 '-hydroxyl azobenzene?PCAZ??3, 5- dicarboxyl-4 '-hydroxyl azobenzene?MCAZ?and 2-carboxyl-5-nitro-4 '-hydroxyl azobenzene?CNAZ?. At the b3 lyp / 6-31 g * basis set level, adopt the method of density functional theory, study the structure and the photoisomerization pathway for this three kind of azobenzene derivatives. The PCAZ, the MCAZ and the CNAZ be Synthesized in diazo coupling reaction. The synthesis of the porous coordination materials with an organic linker having azobenzene as a switch group. The forming mechanism of such materials were revealed by IR spectroscopy,1HNMR spectra and so on. In this thesis, six parts of work are described as following.?1? At the b3 lyp / 6-31 g * basis set level, adopt the method of density functional theory, the photoisomerization pathway for the PCAZ are a rotation of the CNNC dihedral angle, the photoisomerization pathway exist on the MCAZ also the rotation of the CNNC dihedral angle and the inversion of CNN angle are the photoisomerization pathway for the CNAZ.?2?The PCAZ, the MCAZ and the CNAZ be Synthesized in diazo coupling reaction. The yield of the azobenzene derivatives almost 60%⁷5%.?3? The solvothermal method was used to synthesize the coordinationcomplexes containing optical switch.?4?Before UV exposure, the CO₂ uptake of a pristine sample of coordination complexes 1 at room temperature after activation was 10.65 cm3/ g at 1 bar, and the uptake decreased to 5.23 cm3/ g after 24 h of UV irradiation, and then the sample was wrapped with aluminum foil to prevent visible light exposure and kept under 60 °C for 24 h, when CO₂ adsorption was measured again at the same temperature the uptake of a sample was 10.30 cm3/ g, corresponding to an overall decrease of 3.5% in CO₂ uptake when compared to the pristine sample. Before UV exposure, the CO₂ uptake of a pristine sample of coordination complexes 2 at room temperature after activation was 6.91 cm3/ g at 1 bar, and the uptake decreased to 4.19 cm3/ g after 24 h of UV irradiation, and then the sample was wrapped with aluminum foil to prevent visible light exposure and kept under 60 °C for 24 h, when CO₂ adsorption was measured again at the same temperature the uptake of a sample was 6.22 cm3/ g,corresponding to an overall decrease of 10.0% in CO₂ uptake when compared to the pristine sample. The CO₂ uptake of a pristine sample of coordination complexes 2 at room temperature after activation was 4.16 cm3/ g at 1 bar, and the uptake decreased to 2.16 cm3/ g after 24 h of UV irradiation, and then the sample was wrapped with aluminum foil to prevent visible light exposure and kept under 60 °C for 24 h, when CO₂ adsorption was measured again at the same temperature the uptake of a sample was 2.27 cm3/ g, corresponding to an overall decrease of 45.0% in CO₂ uptake when compared to the pristine sample.?5?N2 capacities of coordination complexes 1 at 77 K were tested. The results indicate that the adsorption isotherm of complexes 1 to N2 is the I type of isotherm and its adsorption capacity 734.1cm3/ g at 1 bar. N2 capacities of coordination complexes 2 at 77 K were tested. The results indicate that the adsorption isotherm of complexes 1 to N2 also the I type of isotherm and its adsorption capacity612.7 cm3/ g at 1 bar.N2 capacities of coordination complexes 1 at 77 K were tested.The results indicate that the adsorption isotherm of complexes 1 to N2 is the I type of isotherm and its adsorption capacity 402.9cm3/ g at 1 bar.In this paper, the theory of quantum chemistry calculation research are combining with synthesis preparation, structure characterization and performance testing of experimental research. choosen excellent azobenzene derivatives as a molecular switch, Synthesise three kinds of stable structure of porous materials with optical switch, reveals its e reversible isomerization reaction with CO₂ adsorption, forresearch and development of new reusable CO₂ adsorbent to provide experimental basis and theoretical guidance. Providing experimental basis and theoretical guidance for the research and development of CO₂ adsorbent.