Synthesis,Structure And Properties Of Crystalline Titanium-oxo-clusters

Solar energy plays a very important role in the supply of sustainable energy and the treatment of environmental pollutants.Nano-Ti O₂ is considered as a promising photocatalyst for solar energy conversion and environmental treatment due to its low cost,high efficiency and environmental friendly properties.However,this kind of nanoparticle material also has some disadvantages which cannot be ignored,including the structure is not accurate,the particle size is not uniform,the inorganic-organic interface information is not clear,and the surface composition is uncertain.These factors greatly hinder the further study of these important photocatalytic materials,such as the discussion of catalytic mechanism,the determination of charge transfer path,the rational modification of the surface interface and the exploration of structure-activity relationship.As a molecular model compound for the structure and catalytic performance of nano-sized Ti O₂,crystalline titanium-oxo-clusters with definite structure have gradually become the focus of researchers.Their precise atomic structure information,clear ligand-cluster linkage,adjustable cluster size and good solubility all provide the possibility for further study of their functional-oriented structure design and ultimately optimization of their catalytic applications.In this paper,a series of crystalline titanium-oxo-cluster materials were designed and synthesized by controlling the reaction conditions,and their related properties were explored.This paper mainly contains the following three parts:1:Synthesis,structure and properties of Crystalline titanium-oxo-clusters based on aliphatic ring monocarboxylic acid ligandsUsing cyclopropane,cyclobutane,cyclopentane carboxylic acid and tetramethylcyclopropane carboxylic acid as organic ligands,four crystal clusters were obtained by solvothermal method with metal Ti,respectively:[Ti₈O₈（HBWS）₁₆]_n（1）,[Ti₆O₆（O ⁱPr）₆（HDWS）₄]_n（2）,[Ti₆O₆（OⁱPr）₆（HWWS）₆]_n（3）,[Ti₆O₆（OⁱPr）₆（TCPA）₆]_n（4）.The nuclear cluster type of 1 is the Ti₈O₈ round cluster of the classical titanium-oxo-cluster,2,3,and 4 are double hexagonal stacked octahedral structures.After systematically studying the photodegradation performance of the above four clusters,it is found that they have superior photocatalytic degradation performance.Under the irradiation of xenon lamp,Rhodamine B aqueous solution faded completely in about 100 minutes.In addition,the band gap was be calculated of titanium-oxo-clusters.2 Synthesis,structure and properties of Crystalline titanium-oxo-clusters based on aromatic cyclic monocarboxylic acid ligandsThe zero-dimensional titanium-oxo-cluster was synthesized by the single-tooth coordination strategy of benzene ring monocarboxylic acid.Based on benzoic acid derivatives by introducing different functional coordination groups.A series of 10 zero-dimensional titanium-oxo-clusters were successfully synthesized from isopropyl titanate as titanium source:[Ti₃O（OⁱPr）₈（DMBA）₂]_n（5）,[Ti₆O₆（OⁱPr）₆（TBA）₆]_n（6）,[Ti₆O₆（OⁱPr）₆（PBA）₆]_n（7）,[Ti₆O₆（OⁱPr）₆（BCBA）₆]_n（8）,[Ti₆O₆（OⁱPr）₆（TBBA）₆]_n（9）,[Ti₁₀O₁₂（Oi Pr）₁₀（PTA）₆（DMF）₂]_n（10）,[Ti₁₀O₁₂（OⁱPr）₁₀（DTBA）₆（DMF）₂]_n（11）,[Ti₁₀O₁₂（OⁱPr）₁₀（MDBA）₆（DMF）₂]_n（12）,[Ti₁₀O₁₂（OⁱPr）₁₂（TFBA）₆·（DMF）]_n（13）,[Ti₁₀O₁₂（OⁱPr）₁₀（ASA）₆（DMF）₂]_n（14）.There are three types of nuclear clusters among the 10 clusters:one is the Ti₃O tetrahedral structure with oxygen as the vertex,the other is the hexagonal stacked octahedral Ti₆O₆ core cluster mentioned above,and the third is the rheological cuboid Ti₈O₁₀ core cluster.After systematically studying the photodegradation performance of the above four clusters,it is found that they have superior photocatalytic degradation performance.Under the irradiation of xenon lamp,Rhodamine B aqueous solution faded completely in about 100 minutes.In addition,the band gap was be calculated of titanium-oxo-clusters.3 Synthesis,structure and properties of rare earth doped series crystalline titanium-oxo-clustersA class of bitetra-pyramidal octahedral titanium-oxygen cluster materials was synthesized using 3,5-ditert-butyl benzoic acid（DTBA）as organic ligand by solvo-thermal method using rare earth acetate:[Ti₄Eu₂O₆（Phen）₂（DTBA）₁₀]_n（15）,[Ti₄Gd₂O₆（Phen）₂（DTBA）₁₀]_n（16）,[Ti₄Tb₂O₆（THF）₂（DTBA）₁₀·（THF）₂]_n（17）,[Ti₄Dy₂O₆（THF）₂（DTBA）₁₀·（CH₃CN）₂（TH F）]_n（18）.Among them,15,16 o-phenphenline and 17,18 tetrahydrofuran（THF）were involved in the coordination,and it was found that they had obvious photocurrent response under visible light irradiation.In addition,the band gap was be calculated of titanium-oxo-clusters.