【作者】 李斐；

【导师】 孙立成； 王梅；

【作者基本信息】 大连理工大学 ， 应用化学， 2006， 博士

【摘要】 非血红素铁加氧酶的研究作为生物无机化学领域一个新兴的热点，吸引了众多的关注。基于非血红素铁加氧酶的仿生催化剂能够利用分子氧或H₂O₂等“绿色”氧化剂在温和条件下高效高选择性催化包括烷烃、烯烃、酚等在内的众多有机底物的氧化，对于开发绿色环保氧化工艺具有重要意义。近年来，生物学技术的发展以及众多模型配合物体系的开发使这个领域不断有新的突破。基于这样的研究背景，本论文对烷烃羟基化非血红素铁加氧酶（如铁博来霉素（FeBLM））和儿茶酚内裂解酶（如原儿茶酚3，4-双加氧酶（3，4-PCD））的活性中心进行了化学模拟，设计合成了一系列非血红素铁功能模型配合物，并重点考察所得铁配合物催化烷烃羟基化的性能和对3，5-二叔丁基邻苯二酚（H₂DBC）内裂解反应的活性。 本文合成了具有灵活配位性质的N₄O配体N-（2-吡啶甲氧基乙基）-N，N-二（2-吡啶甲基）胺（L¹），晶体结构显示L¹可以在单核铁配合物中充当三齿或五齿配体，也可以和Fe（ClO₄）₃形成μ-oxo双核铁配合物。在温和条件下，以H₂O₂为氧化剂，[FeL¹Cl]PF₆（Fe2）为催化剂催化烷烃的羟基化反应，较好的模拟了FeBLM的功能，显示出高于以往N₅配体配位非血红素单核铁配合物的化学选择性（A／K=2.4），表明向配合物引入一个弱配位醚氧原子有利于基于金属氧化物种的反应途径。同样具有高选择性的fac-构型FeL¹Cl₃（Fe3）则显示了高于mer-构型N₃配位铁配合物的催化活性和选择性（A／K=2.3）。催化数据表明，在mCPBA体系中，N₄O和N₄O₂配位铁配合物以非血红素铁加氧酶基于金属的反应机理催化烷烃氧化，显示出高活性和高区域选择性（3°／2°=18.5-34.4）。此外，通过UV-Vis推测N₂O₂配体配合物[FeL²]（ClO₄）₂（Fe6，L²=N，N-二（2-吡啶甲氧基乙基）-N-（2-吡啶甲基）胺）在H₂O₂体系中生成Fe^Ⅲ-OOH过氧中间物种。 本论文将三角锥型N₃O配体配位μ-alkoxo双核Fe（Ⅲ，Ⅲ）配合物[FeL⁸（NO₃）]₂（NO₃）₂(Fe11，HL⁸=N，N-二（2-（吡啶甲基）-N-羟乙基胺）作为3，4-PCD活性中心的功能模型，对其进行了光谱学碱滴定，发现Fe11的烷氧基有效模拟了Tyr447分子内在碱的功能，与底物结合时能接受底物的质子，并从金属中心解离。动力学研究表明体系中只需加入少量的碱（0.8当量哌啶），就可以达到较高的儿茶酚1，2-双加氧酶内裂解活性(k=0.38 M^-1s^-1)。此外，本文将含乙二胺骨架的不对称线型N₃O配体配位铁配合物FeL^6aCl₂(Fe9a，HL^6a=N，N’-二甲基-N-（2-吡啶甲基）-N’-（2-羟基苯甲基）乙二胺)和FeL^6bCl₂(Fe9b，HL^6b=N，N’-二甲基-N-（2-吡啶甲基）-N’-（2-羟基-5-氯-苯甲基）乙二胺)应用到3，4-PCD活性中心结构的模拟当中。由其晶体结构发现配合物的两个易变配位点处于相似的化学环境之中，从而降低了底物加合物的半醌自由基性质，导致对于H₂DBC的内裂解失去活性。更多还原

【Abstract】 The research on non-heme iron oxygenases has emerged as a hot project in bioinorganic field, which has attracted much attention. Under mild conditions, the bio-inspired catalysts based on non-heme iron oxygenases can selectively and efficiently catalyze oxidation reactions of a large range of substrate such as alkanes, alkenes and phenols by using "green" oxidants. It may give a promising way to substitute present oxidation processes. In recent years, the development of biological techniques and biomimetic model systems has led to exciting breakthrough in the field of non-heme iron oxygenases. Encouraged by these achievments, in this thesis, the work focused on mimicking the function of non-heme iron oxygenases, especially those for alkane hydroxylation （iron bleomycin （FeBLM）） and catechol’s intradiol cleavage dioxygenase （protocatechuic 3,4-dioxygenase （3,4-PCD））. A series of iron complexes were synthesized as functional models of non-heme iron oxygenases, their catalytic properties for the hydroxylation of alkanes and activities for the catechol intradiol-cleavage were investigated.A versatile ligand L¹ (N-（2-（pyridylmethoxyethyl）-N,N-bis（2-pyridylmethyl）amine） and its iron complexes were synthesized. The crystal structures of the iron complexes show that that L¹ can act as a tridentate or pentadentate ligand in monoiron complexes and μ-oxo dinuclear iron complex which was obtained from the reaction of L¹ with Fe（ClO₄）₃. Under mild conditions, the catalytic property of complex [FeL¹Cl]PF₆ （Fe2） was explored by using H₂O₂ as oxidant, which exhibited higher chemo-selectivity than previously reported N₅ ligand iron complexes （A/K = 2.4）. The result manifests that the weak coordination of ether oxygen atom from L¹ benefits the metal-based oxidation pathway. Complex FeL¹Cl₃ （Fe3） with a fac-configuration showed a high selectivity in alkane hydroxidation as well as Fe2. The activity and selectivity of Fe3 are higher than the N₃-coordinate analogue with a mer-configuration （A/K = 2.3）. While in mCPBA system, the complexes bearing N4O and N₂O₂ ligands exhibited high activities and high regioselectivities （3°/2° = 18.5-34.4）. An Fe^III-OOH species was detected when the cyclohexane oxidation catalyzed by [FeL²]（ClO₄）₂ （Fe6, L² =N,N-bis（2-pyridylmethoxyethyl）-N-（2-pyridylmethyl）amine） containg an N₂O₂ ligand was monitored by UV-Vis spectrometry.The μ-alkoxo diiron（III,III） complex [FeL⁸（NO₃）]₂（NO₃）² （Fe11, HL⁸ = N,N-bis（2-pyridylmethyl）-N-hydroxylethylamine） containing tripodal N₃O ligand was更多还原