水对二氧化碳插入TpRu(PPh_3)(CH_3CN)H生成甲酸根配合物的影响(英文)  

Water Effect on CO_2 Insertion into Ruthenium Hydride Bond of TpRu(PPh_3)(CH_3CN)H to Form Formate Complexes

作　　者：尹传奇[1] 吴莉[1] 付晓滨[1] 许志涛 吴少文[3] 

机构地区：[1]武汉化工学院制药系,湖北武汉430073 [2]香港科技大学化学系 [3]香港理工大学应用生物及化学科技学系

出　　处：《分子催化》2003年第1期22-28,共7页Journal of Molecular Catalysis(China)

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.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.

关 键 词：水 TpRu(PPh3)(CH3CN)H 甲酸根配合物 钌配合物 亲电性 氢键 过渡态 能垒 二氧化钛 

分 类 号：O614.821[理学—无机化学]