The Rational Syntheses,Structures And Characterizations Of Novel Titanium Oxo-clusters

Photocatalytic technology is able to direct use of natural resources in the clean and renewable solar energy for the catalytic oxidation of pollutants,at the same time,the significant advantages of the photocatalytic technology are a high degree of mineralization of pollutants and low selectivity.Therefore,photocatalytic technology can contribute greatly in environmental protection.Photocatalytic has a broad application prospect in the degradation of pollutants and other fields.The utilization of solar-driven photocatalytic processes underlying hydrogen production,water decontamination,organic synthesis and solar cell,by employing semiconductor materials is of great interest since it is a clean,environmentally friendly energy source.Titanium oxide?TiO₂?has been the most promising and popular photocatalyst due to its nontoxicity,chemical inertness,abundance,and high photostability,and high efficiency.Hitherto,it is still great challenge to understand the light carrier separation,transmission and recombination course within the photocatalytic processes,which critically limits the rationally syntheses of more efficient photocatalytic semiconductor materials.The titanium oxo-clusters,as the model of the bulk nanoscale titanium oxides,offer the opportunity to understand theinformation of the bulk nanoscale oxides in terms of both atomic structure and chemical reactivity.In this dissertation,a series of novel titanium oxo-clusters have been synthesized by employed carboxylic acid ligands and Ti?OⁱPr?₄.Their structures,optical properties,degradation of RhB,H₂ evolution from the aqueous solution have also been studied.The studied works are concluded in the following:?1?Five titanium oxo-clusters based monocarboxylic acid organic ligand had synthesized as listing below:Ti₄O₂?OⁱPr?₁₀?Bz?₂ Complexe D-1 Ti₄O₂?OⁱPr?₁₀?1-Nap?₂ Complexe D-2 Ti₄O₂?OⁱPr?₁₀?2-Nap?₂ Complexe D-3 Ti₆O₄?OMe?i₄?Bz?₂ Complexe D-4 Ti₈O₈?OMc?₁₆]-2CH₃CN Complexe D-5?2?Eight titanium oxo-clusters based dicarboxylic acid organic ligand had synthesized as listing below:Ti₆O₂?OⁱPr?₁₆?mal?₂ Complexe S-1 Ti₆O₂?OⁱPr?₁₆?2,6-2Me-3,5-pydca?₂ Complexe S-2 Ti₆O₃?OⁱPr?₁₄?male?₂ Complexe S-3 Ti₆O₃?OⁱPr?₁₄?mal?₂ Complexe S-4 Ti₆O₃?OⁱPr?₁₄?suc?₂ Complexe S-5 Ti₉O₃?OⁱPr?₂₄?chdca?₃ Complexe S-6 Ti₁₂O₄?OⁱPr?₃₂?BDC?₄ Complexe S-7 Ti₈O₅?OMe?₁₈?suc?₂·MeOH-H2_O Complexe S-8?3?Eight heterometal titanium oxo-clusters based monocarboxylic acid organic ligand had synthesized as listing below:Ti₅Cu₄O₆?OMc?₁₆ Complexe Y-1 Ti₅Cu₄O₆?Bz?₁₆·MeCN Complexe Y-2 Ti₅Cu₄O₆?1-Nap?₁₆ Complexe Y-3 Ti₄Zn₄O₆?OMc?₁₂ Complexe Y-4 Ti₁₂Cd₅ O₁₈?Bz?₂₁?OⁱPr??MeCN?Complexe Y-5 Ti₁₂Mn₅ O₁₈?Bz?₂₁?OⁱPr??MeCN?Complexe Y-6 Ti₂Co₄O₂?OMc?₁₀?OOCCH₃?₂?H₂O?2-MeCN Complexe Y-7 Ti₂Co₄ O₂?Bz?₁₀?OOCCH₃?₂?H₂O?₂ Complexe Y-8All of the complexes were determined by X-ray single crystal diffractive technology.The properties of most compounds have been characterized with X-ray powder diffraction,infrared spectroscopy,ultraviolet-visible diffuse reflection spectrum.The structure of all compounds had analysized and summarized in detail.The single crystal structure analysis shows all the complexes exhibits zero dimension.Notable,the two trinuclear titanium oxo-clusters are connected by pairs of dicarboxylic acid ligand in the compound S-1,S-2.The two trinuclear titanium oxo-clusters of compound S-3,S-4,S-5 linked by pairs of dicarboxylic acid ligand and ?2-O bridge.However,there are three trinuclear titanium oxo-clusters in the compound S-6,the three trinuclear titanium oxo-clusters linked each other by 1,4-chdca.At the same time,the four trinuclear titanium oxo-clusters of compound S-7 are connected each other by BDC2-ligand.The photocatalytic degradation of RhB for most compounds have been characterized.In comparison,the degradation effect of the titanium oxo-clusters based monocarboxylic acid organic ligand performed well,namely,the degradation rate of compound D-2,D-3 was 99%when the irradiance time for 24 min.The photochromic behavior ofthe complexes S-2,S-3,S-4,S-5 were analysed by EPR.Simultaneously,we also studied the H₂ evolution for compound Y-1,Y-2,Y-3,Y-4 from the aqueous solution of disodium ethylenediaminetetraacetate under artificial solar light irradiation.