【作者】 王云霞；

【导师】 孙英姬；

【作者基本信息】 大连理工大学 ， 无机化学， 2010， 硕士

【摘要】 本论文围绕当今国际上有关分子氧的活化及利用分子氧的生物氧化等研究热点,以分子水平上阐明Glu102的羧基、His98、金属中心离子、配体的电子效应及空间效应等对酸式还原酮双加氧酶(Acireductone dioxygenase简称ARD)活性中心的结构、反应性、分子氧的活化机理的影响及其构-效关系为目的,开展了如下探索性的工作：(1)设计合成了分子内苯基侧臂上导入羧基,而且羧基的对位导入供电子基甲基和一个吡啶环6-位导入苯基的甲基二吡啶胺(bis(2-pyridylmethyl)amine)两个新的ARD模型配体L8H和L9H,并用IR、质谱、1H NMR及熔点测定等方法进行了表征。(2)用所合成的模型配体以乙酸根作为共配体,设计合成了6个新的相应过渡金属M(II)(M:Ni、Fe、Cu)的ARD二元模型配合物,并用IR、UV-Vis、ESI/MS、X射线衍射等方法进行了表征。解析了2个铜模型配合物3和6的X射线晶体结构,分别具有单核四方锥和双核四方锥配位环境。(3)用UV-Vis追踪的方法研究了所合成的二元模型配合物分别与模型底物S1和S2及分子氧的反应性,并通过比较研究初步探讨了金属中心离子、分子内导入的羧基、配体的电子效应及空间效应对ARD模型配合物的结构、反应性的影响及其构-效关系,得到了一些重要的结论,而这方面的研究尚未见文献报道。(Ⅰ)相同配体、不同金属离子：铁模型配合物的反应性优于镍模型配合物,即Fe>Ni。(Ⅱ)相同金属离子、不同配体：羧基的对位导入给电子基团甲基的L8H模型配合物的反应性不如没有取代基的L1H模型配合物,即LSH<L1H。(Ⅲ)相同金属离子、不同配体：吡啶环上6-位导入取代基的模型配合物的反应性不如未导入取代基的模型配合物,而且取代基越大,其反应性越差,即反应性顺序是：L9H<LH<L1H。这主要是因为吡啶环上6-位取代基的空间位阻所致。(Ⅳ)相同金属、相同配体时：模型配合物对模型底物S2的反应性较S1好,即活性顺序为：S2>S1。(4)NiⅡ模型配合物催化氧化模型底物S2的反应产物中有苯甲酸,而FeⅡ模型配合物的产物中却有α-氧代苯乙酸,这与天然酶Ni(Ⅱ)和Fe(II)-ARD的催化反应产物相一致,很好地模拟了这两种天然酶。有关同时生物模拟Ni(Ⅱ)和Fe(II)-ARD一对天然酶的研究尚未见文献报道。更多还原

【Abstract】 Dioxygen activation and biomimetic oxidation of carbohydrate is one of the most active areas, and have been received considerable attention recently. This work focus on this active area, aiming at getting insights into the catalytic role of Glu102, His98、metal ion effects, electronic effects and steric effects on the structure and reactivity of acireductone dioxygenase (ARD).Two new model ligands bis(2-pyridylmethyl)amine model ligand carrying para-methyl-ortho-benzoic acid derivative as the ligand sidearm L8H and (6-phenyl-2-pyridylmethyl)(2-pyridylmethyl)amine model ligand carrying ortho-benzoic acid derivative as the ligand sidearm L9H have been designed, synthesized, and characterized by IR, UV-Vis, ESI/MS,1H-NMR and melting point measurement.Six novel binary complexes M(II) (M:Ni, Fe, Cu) have been designed, synthesized, and characterized as the structural and functional models for the active site of ARD. Our design of model ligands and complexes focus on both catalytic site and substrate binding site of the enzyme. The structures of complex 3 and 6 have been determined by X-ray diffraction.The reactivity of the model complexes towards model substrates and dioxygen have been investigated by UV-Vis monitoring. Although the structures of the model complexes are similar, the reactivities show notable differences. The caboxylate effects, metal ion effects, electronic effects, and steric effects on the reactivity of the model complexes have been investigated. The conclusions of our research are as follows:(I) With the same ligand, the reactivity of different metal ion model complexes show some differences and in the order:Fe> Ni.(II) With the same metal ion, the reactivity of para-CH3 substituted one is much lower than non-substituted one:L8H< L1H.(III) With the same metal ion, the reactivity of substituted by different bukyl groups are quite different and in the order:L9H< LH< L1H.(IV) With the same metal ion and ligands, the reactivity towards S2 is better than S1: S2> S1.The reaction products of model complexes towards model substrate S2 and dioxygen have been investigated by ESI/MS. The products of Ni(II)-complexes contain benzoic acid, while the products of Fe(II)-complexes containα-oxo-benzeneacetic acid. This results are consistent with the corresponding native Ni(II) and Fe(II)-ARD, just mimic to the catalytic reaction of native Ni(II) and Fe(II)-ARD.更多还原