【作者】 曾伟；

【导师】 秦圣英；

【作者基本信息】 四川大学 ， 有机化学， 2003， 博士

【摘要】 仿加氧酶研究不仅对揭示生物体内氧的可逆键合、活化和氧化反应机制具有重要的理论意义，而且在化学分离氧和温和条件下实现氧化反应的高效高选择性等方面也表现出广阔的应用前景。许多研究表明，键连的冠醚、尤其是氮杂冠醚能参与某些功能分子的协合作用，但迄今为止，键连冠醚的Schiff碱衍生物极少，更未见有关氮杂冠醚Schiff碱金属络合物的氧合、催化氧化和仿单加氧酶功能的研究。为此，本文设计合成了一系列新型的以水杨醛亚胺和苦胺基作侧臂的N-支套索冠醚，深入系统地研究了它们的过渡金属配合物中冠醚环及其键连方式、键连部位、冠环大小、离配位中心的距离、环中杂原子、配合的碱金属离子，配体芳环上取代基对其二氧亲合性和仿生催化氧化性能的影响，以及对碱金属盐和有机胺的选择变色作用等，并探寻其中的某些规律性，获得了一系列具有重要理论意义和应用前景的创新结果，为今后仿酶新模型的设计合成提供了许多有益的信息。 借助于氮杂冠醚环中仲氨基及苯并冠醚芳环的反应活性和Schiff碱的易修饰性，将二者构建成两大系列共17个新型配体HL^sn，H₂L^dm（n=3-17，m=4,6）和相应的34个过渡金属配合物ML₂^sn和ML^dm，M=Co（Ⅱ）or Mn（Ⅲ）Cl，n和m同上，并以IR、¹HNMR、MS和元素分析进行确认。HL^s4，HL^s15和CoL₂^s4晶体的X-Ray分析表明：受氮杂冠环中氮原子的三棱锥构象控制，氮杂冠环比全氧冠环更靠近配位中心，使能更有效地调控配位中心周围的微环境，从而达到了预期的设计目的。 系统地考查了配体结构对Schiff碱Co（Ⅱ）配合物氧合性能的影响，在-5℃-25℃范围内测定了它们在二甘醇二甲醚溶液中的氧合常数Ko₂和热力学参数ΔH⁰、ΔS⁰，并通过UV-Vis跟踪，进一步证实了它们良好的载氧活性。结果表曾伟四川大学博士学位论文2003年明:1.相对于非冠醚类似物而言，co（II） schiff碱模型物中键连的冠醚环能大大提高氧合速度和最大氧合容量，其K。:一般能提高^l个数量级，且冠环的键连方式、杂原子、数量对氧合性能都具有明显影响;2.键连的冠环及其配合的碱金属离子均能增强载氧活性（K。:值增加²0%）;3.与全氧冠环相比，氮杂冠环因更能靠近活性中心而使配合物的二氧亲合性显著提高。 应用冠醚化锰（II 1） Schiff碱模拟P一450细胞色素单加氧酶催化功能，以分子氧（02）为氧源，在近似生理条件下实现了对苯乙烯的催化氧化。系统考查了冠醚环及其直径大小、结构类型、键连方式、键连部位和与活性中心的距离对配合物催化氧化性能的影响。新奇的是，键连的冠醚环能改变苯乙烯的催化氧化反应历程:冠醚化Mn（III）schiff碱能催化氧化苯乙烯为苯甲醛，选择性100%，TOF可达36:而非冠醚类似物的主要催化氧化产物为苯基环氧乙烷，其选择性>80%，TOF可达25;另外，依据键连冠环的固有特性，添加直径合适的碱金属离子，能使苯乙烯转化率和ToF值增加一倍多。反应动力学研究进一步表明，这些催化氧化反应都具有酶促反应特征。 作为对二甲苯均相氧化反应的催化剂，进一步考查了Mn（III）S chiff碱的结构及添加碱（碱土）金属盐等对催化氧化性能的影响。结果表明:1.键连的冠醚环均能显著提高催化活性，并大大缩短反应诱导期5一10h，使ToF从21⁶0提高到152一222，约增加了5一7倍;冠环的键连方式和部位以及与活性中心的距离对催化活性影响明显;2.添加与冠醚环直径相匹配的碱金属离子能显著提高催化活性;3.锰（III）配合物的催化活性与配体相同的钻（II）配合物的二氧亲合性存在一定的关联性和某些相似的规律性。通常，氧合常数K。:较大的配合物的反应诱导期较短;4.依据结果提出了可能的反应机理。 设计合成了三个具有分子隙缝的、以苦胺基为侧臂的N-支套索冠醚，利用其生色基和 UV一VIS吸收光谱，简便地研究T，冠环大小、键连基团对碱金属盐和有机胺选择变色作用的影响。结果表明:在多种碱金属盐中，只有N-（4一苦胺基苯基）氮杂一12一冠一4对其中的LICol;才具有最佳选择变色作用（△蝙ax二一118Iun），同山，它还能以三点氢键作用和静电作用为主要推动力，对甲胺(c H3N场勺也具有良好的识别能力。更多还原

【Abstract】 Investigation of mimetic oxygenase not only has important theoretic significance to reveal reversible bonding and activating oxygen as well as the mechanism of oxidation reaction in organism, but also is promising applicable in chemically separating oxygen and realizing high efficiency and selectivity of catalytic oxidation reaction under a mild condition. Many researches have indicated that synergetic action could be operated between the functional groups and the bonded crown ether, especially for the aza crown ether. Unfortunately, up to now very limited studies on the crowned Schiff basees were reported, needless to say, no studies on the oxygenation, catalytic oxidation and mimetic mono-oxygenase performance of aza crowned Schiff base complexes were carried out. In this paper, A series of novel aza crowned mono and bis-Schiff base ligands and its transition-metal complexes were synthesized, the further study on the influence of the introduced crown ring, its size, bonded fashion, position to Schiff base, distance from the coordination center, hetero-atom of crown ring, its complexation with the added alkalic (or alkalic earth) cation as well as the substitutents in the aromatic ring on the dioxygen affinities and biomimetic catalytic oxidation performance were investigated. Series of useful and creative results have been obtained, which give much helpful information to the design and synthesis of new models of mimetic oxygenase.Two series of novel ligands HLsn, H2Ldm (n= 3-17, m= 4, 6) and its transition-metal complexes were synthesized by the reaction sites of secondary amino group of aza crown ether and aromatic ring of benzo crown ether as well asthe convenient modification of SchifF basea, and characterized by IR, ’HNMR, MS and elemental analysis. The crystallographic data of HLs4, HLs15 and CoL2s4 indicates that the special conformational control of nitrogen atom in aza crown ring makes aza crown ring bonded to Schiff base close nearer to the coordination center, and control more efficiently the coordination environment compared with the benzo crown ring.The effect of ligand structure on the oxygenation performance of Co(II) complexes was investigated systematically. Their equilibrium constants Koj and thermodynamic constants ΔH0 and ΔS0 for oxygenation in the presence of diethyleneglycol dimethy ether as solvent and pyridine as axial ligand over a range of -5 0C to 25 0C were determined. The further UV-Vis spectra on the oxygenation demonstrated that the Co(II) complexes possess excellent dioxygen affinities. The results indicated: 1. The oxygenation equilibrium constants Ko2 of all the crowned Schiff base Co(II) complexes was higher than that of the corresponding uncrowned analogues, and the crown ring boned to Schiff base resulted to higher oxygenation velocity and oxygenation capacity, moreover, the bonded fashion and size and number of crown ring all effected the oxygenation. 2. The crown ring and alkalic ion complexed by the crown ring can conduce to the formation and stability of bond of Co-02. 3. aza crown ring close nearer to the coordination center and result to a higher dioxygen affinities compared to the peroxa crown ring.With the aid of Schiff base Mn(III) complexes as cytochrome P-450 article models, catalytic oxidation of olefm with molecular oxygen (O2) as terminal oxidants was carried out under an approximate physiological condition. The influence of crown ring and its size, structure,’bonding fashion, position and the distance from activity center on the oxidation of styrene were examined. It is surprising that the bonded crown ring changed wholly the reaction path of catalytic oxidation of styrene. Crowned Mn (III) Complexes catalyzed the styrene to benzaldehyde-at 100% selectivity and 36 of TOF, but the uncrowned analogues catalyzed oxidation for styrene-to-phenyl-ethylene-epoxide at > 80% of selectivity and 25 of TOF, moreover, the conv. and TOF of catalytic oxidation for styrene tobenzaldehyde has increased by 100% ~ 240% because of the addition of alkalic更多还原