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水对二氧化碳插入TpRu（PPh₃）（CH₃CN）H生成甲酸根配合物的影响（英文）

Water Effect on CO₂ Insertion into Ruthenium Hydride Bond of TpRu（PPh₃）（CH₃CN）H to Form Formate Complexes

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【Author】 YIN Chuanqi1, WU Li1, FU Xiaobin1, XU Zhitao2, NG Siuman3(1. Department of Pharmacy, Wuhan Institute of Chemical Technology, Wuhan 430073, China; 2. Department of Chemistry, The Hong Kong University of Science & Technology, Hong Kong, China; 3. Department of Applied Biology & Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China)

【机构】武汉化工学院制药系；香港科技大学化学系；香港理工大学应用生物及化学科技学系湖北武汉430073；湖北武汉430073；香港；香港；

【摘要】分别研究了在干燥THF及H2O/THF条件下CO2与TpRu(PPh3)(CH3CN)H(Tp=Hy-drotris(pyrazolyl)borate)的反应,发现水对CO2插入TpRu(PPh3)(CH3CN)H的反应具有显著促进作用.原位高压NMR研究显示,在水存在下,CO2插入Ru-H键形成水合甲酸根配合物TpRu(PPh3)(CH3CN)(η1-OCHO)·H2O,其中甲酸根配体与溶剂中水分子形成分子间氢键.B3LYP水平的理论计算表明,CO2插入TpRu(PPh3)(CH3CN)H中Ru-H键的能垒由于水的存在而显著降低;在过渡态,CO2分子中碳原子的亲电性由于其氧原子与水分子形成氢键而得到增强.TpRu(PPh3)(CH3CN)(η1-OCHO)·H2O很快转化为另一甲酸根配合物TpRu(PPh3)(H2O)(η1-OCHO),并与之达成平衡.后者由于甲酸根配体与水分子配体间形成分子内氢键而稳定.更多还原

【Abstract】 A promoting effect of water on CO2 insertion into TpRu(PPh3)(CH3CN)H (Tp = Hydrotris(pyrazolyl)borate) is observed. In situ highpressure NMR monitoring shows that CO2 readily inserts into Ru-H to form the hydrated metal formate TpRu(PPh3)(CH3CN)(η1OCHO)·H2O, in which the formate ligand is intermolecularly Hbonded to a water molecule. Theoretical calculations carried out at the B3LYP level show that reaction barrier of the CO2 insertion is significantly reduced in the presence of water. In the transition state of the process, electrophilicity of the carbon center of CO2 is enhanced by the formation of Hbonds between its oxygen atoms and H2O. The hydrated formate species TpRu(PPh3)(CH3CN)(η1OCHO)·H2O comes into equilibrium rapidly with another metal formate species TpRu(PPh3)(H2O)(η1OCHO), in which the coordinated H2O is intramolecularly Hbonded with the formate ligand.更多还原