Construction And Catalytic Performance Of Hexanuclear Rare-earth Oxygen Cluster Organic Framework Based On 1,2-di(5-isophthalato)ethylene Ligands

Using hexanuclear rare earth metal clusters and reducing ligands to form a polymetallic active site lanthanide metal-organic frame material,it can not only show the unique structure,but also possess the luminescent,conductive and magnetic properties of lanthanide ions.Building a mechanism frame of multi-core lanthanide metal oxygen cluster MOF with excellent performance and diverse structure and to exploring its application in the fields of catalysis,conductivity,magnetism,gas adsorption and separation,which is of great significance for the rich diversity of multifunctional molecular materials.In this thesis,five hexanuclear rare earth oxygen cluster MOF were synthesized by 1,2-two（5-isphthalate）ethylene ligands.Through the basic characterization and specific analysis of its structure,and explore its function.The main study conclusions are summarized as follows:1.A series of isomorphic hexanuclear rare earth oxygen cluster MOFs:{Ln₆（μ₃-OH）₈（H₂O）₆（SBTC）₃[（CH₃）₂NH₂)]₂·DMF}_n[(Ln=Eu（1）,Dy（2）,Gd（3）,Tb（4）,Yb（5）].According to the single crystal structure,the MOF 1-5 is crystallized in the tripartite crystalline R 3 c space group and the rare earth ions are all coordinated by nine.Topological analysis shows that the hexanuclear rare oxygen cluster MOFs 1-5 has the same structure,which both are 4,12-connected.The conductive test results showed that the conductivity of hexanuclear oxygen clusters MOFs 1,2,4 could reach 1.80×10^-3S cm^-1,1.829×10^-5S cm^-1and 1.926×10^-4S cm^-1.Compared with other reported MOFs,they have excellent electrical conductivity and can be used as potential conductive materials.MOFs 2,3and 4 were tested for antiferromagnetic coupling of MOFs 2 and 4.The-ΔS_mof the hexanuclear rare earth oxygen cluster MOF 3 reaches 31.90 J kg^-1K^-1at 5 T and 2 K.The magneto-thermal effect is obvious,and it can be used as a potential magnetic refrigeration material.2.The photocatalytic CO₂reduction reaction of he hexanuclear rare oxygen cluster MOFs 1 was investigated by the controlled variable method.That photocatalytic reduction of CO₂in acetonitrile and aqueous solvent with triethanolamine as a sacrificial agent gave CO and H₂with CO and H₂yields of 663.00μmol·g^-1h^-1and 41.18μmol·g^-1h^-1,Respectively,with a selectivity of 94.2%.After five cycles of catalysis,the structure of Eu-MOF did not change significantly and the CO yields reached 558.52μmol·g^-1h^-1.In summary,Eu-MOF are a good catalyst for the photocatalytic reduction of CO₂.