| In the past few decades,new functional metal organic framework?MOF?compounds have attracted wide attention in the field of porous materials due to their structural designability,large specific surface area,and functional controllability.As we all know,a serious ploblems of environmental pollution and energy shortage are facing mankind today.It is regarded as one of the best ways to solve these problems about how to effectively use solar energy through photocatalytic technology.Therefore,the design and development of the metal-organic framework materials which are used for photocatalytic technology is a hot spot of research.In this study,the novel visible-light-responsive Ln-MOFs compounds with different structural characteristics was prepared by the coordination sites between an aromatic conjugated organic ligand accompanied by visible light absorption and rare earth ions.The structure of the crystal was characterized by single crystal X-ray diffraction,and its physical and chemical properties were characterized in detail using a variety of characterization methods such as powder X-ray diffraction,infrared,solid ultraviolet,and thermogravimetry.More importantly,we investigated the photocatalytic properties and reaction mechanism of the aerobic oxidation of small molecular organic substrates by the prepared Ln-MOFs compounds.The specific research content is as follows:1.A new three-dimensional metal-organic framework compound 1 was synthesized by solvothermal reaction of conjugated anthracene dicarboxylic acid ligand?ADBEB?with rare earth ion(Nd3+).Its molecular formula is[Nd?ADBEB?1.5?H2O?3]·2DMA.The physicochemical properties tests show that the synthesized compound 1 has good chemical,and exhibits a wide light absorption in the visible light region.Then we explore the photocatalytic aerobic oxidation properties of compound 1 as a visible light photocatalyst for small molecule compounds such as organic amines and organic sulfur.The photocatalytic reaction experiments show that the oxidative dehydrogenation of organic amines and the selective oxygenation of organic sulfur compounds have shown good photocatalytic activity and product selectivity.Thus,imines and sulfoxides which are widely used in synthetic chemistry and pharmaceutical industry are prepared.Studies on the photocatalytic mechanism show that the Nd-MOF catalyst excited by visible light undergoes electron transfer,thereby generating a highly reactive superoxide radical intermediate.At the same time,experiments also show that after photogenerated charge separation,oxidative holes have an important effect on the reaction.This research enriched the types of MOF photocatalysts capable of visible light-driven organic conversion.2.We prepared a novel 3D metal-organic framework compound 2,Dy4?ADBEP?3·2DMF·4H2O,using conjugated anthracene tetracarboxylic acid ligand?ADBEP?and rare earth ion(Dy3+)by solvothermal method.Physicochemical properties of the compound indicate that the compound has good thermal stability and exhibits a wide absorption band based on ligand absorption in the visible light region.Subsequently,we explored the photocatalytic reaction of benzylamine aerobic coupling using compound 2 as a photocatalyst.The experimental results show that compound 2 exhibits good photocatalytic properties in the oxidative coupling reaction of a series of benzylamine substrates. |
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