【作者】 蒋维东；

【导师】 陈华；

【作者基本信息】 四川大学 ， 有机化学， 2007， 博士

【摘要】 金属配合物特别是由金属配合物与表面活性剂形成的金属胶束作为一类模拟水解酶被广泛地应用在酯的催化水解领域。本论文系统地研究了冠醚化的单(双)Schiff碱配合物与双子表面活性剂和双长链表面活性剂形成的金属胶束对α-吡啶甲酸对硝基苯基酯(PNPP)和二(对硝基苯酚基)磷酸酯(BNPP)水解的促进作用。同时，也考察了冠醚化的单(双)Schiff碱配合物结构对羧酸酯和磷酸酯水解速率的影响。并首次将胶束概念引入到HPNP(RNA的模型底物)的水解剪切反应中，并获得了一些有趣的信息。本文合成了一系列对称的、非对称的单(或双)Schiff碱金属配合物，并分别考察了它们与双子表面活性剂和传统的表面活性剂形成的金属胶束对羧酸酯PNPP和磷酸二酯BNPP水解的催化性能。研究结果表明，被Schiff碱金属配合物与双子表面活性剂形成的新型金属胶束催化的PNPP和BNPP的水解速度均比传统的表面活性剂胶束中更快，这可能与双子表面活性剂本身独特的结构有关。另外，两种非对称Salen-Mn(Ⅲ)和Salen-Co(Ⅱ)配合物与双长链表面活性剂DHAB形成的金属胶束催化BNPP的水解也达到7个数量级的速率增加。实验表明，双子和双长链表面活性剂胶束都是比较理想的反应介质，这为人工模拟水解酶的开发和利用提供了有用的信息。本论文对配合物本身的结构与其催化性能之间的关系进行了深入的讨论。研究发现，配体中取代基的吸(或排)电子性对中心金属Lewis酸性的影响除与其吸(或排)电子性本身的强弱有关之外，与取代基所键连位点离中心金属的距离远近也有着密切关系，这与经典的诱导效应规律是一致的。另外，催化剂的活性也受到催化剂活性中心的开放程度的制约。同时也观察到，即使为相同的挂接取代基团(冠醚或吗啉)，在不同骨架的配合物中其对催化剂活性的影响可能相差甚远，甚至涉及到影响因素的主次转换。考察了不同的中心金属对催化剂活性的影响，发现金属离子的荷径比是影响催化剂性能的重要因素之一。首次将胶束概念引入到RNA模型底物HPNP的水解剪切反应体系中。本文初步研究了一种咪唑衍生物为配体的锌(Ⅱ)配合物分别在双子表面活性剂16-2-16胶束和CTAB胶束中催化HPNP水解的反应性。结果表明，双子表面活性剂16-2-16胶束中HPNP水解速率比在CTAB胶束中高出1.5倍。同时还发现，在催化剂和底物HPNP的水溶性都十分优良的均相水体系中加入阳离子表面活性剂，可大大提高HPNP水解的速率。并尝试提出了“胶束-HPNP-催化剂”的“三明治吸附模式”，并运用此“三明治吸附模式”合理地解释了本实验中有趣的实验结果。突破了表面活性剂通常作为添加剂提高两相反应传质速度以加快催化反应速度的经典理论，拓展了表面活性剂的应用范围。更多还原

【Abstract】 Metal complexes, especially metallomicelles formed by metal complex and micelles are widely employed as artificial hydrolases to catalyze the hydrolytic cleavage of carboxylic acid esters and phosphate esters. The cleavage of p-nitrophenyl picolinate (PNPP) and bis(p-nitrophenyl) phosphate (BNPP) catalyzed by metalomicelles, which is formed by crowned Schiff base metal complexes and Gemini (or double long-chain) surfactant micelles, has been studied systematically in this dissertation. Moreover, the effects of structure of complex on the hydrolytic rate of carboxylic acid esters and phosphate esters have been studied. Especially, micelle-catalyzed hydrolysis of HPNP (a RNA model) has firstly been investigated and some interesting information has been gained.A series of symmetrical (or unsymmetrical) single (or double) Schiff base metal complexes have been synthesized. And, their catalytic activities for the hydrolysis of PNPP and BNPP in Gemini surfactant micelles and conventional CTAB micelles have been investigated, respectively. The results show that the hydrolytic rates of PNPP and BNPP in Gemini micelles are greater than that in CTAB micelles, which may be due to the unique structure of Gemini surfactant. In addition, a seven-orders of magnitude rate acceleration has been observed in the hydrolysis of BNPP catalyzed by the two metallomicelles formed by the double long-chain surfactant DHAB and the unsymmetrical Salen-Mn(III) (or Salen-Co(II)). Observations imply that both Gemini and double long-chain surfactant micelle are the ideal reaction media, which provides useful information for the design of effective artificial hydrolases.The relationship between the catalytic activity and structure of complexes has been deeply discussed in the dissertation. The experimental results reveal that the key effect of the substitutes of ligand on the Lewis acidity of central metal is not only depend on the intrinsic electron-withdrawing (or -donating) property of substitute but also on the linked site of substitutes, which is accordance with the classic inductive effect theory. In addition, the catalytic activity of catalyst is also correlative to the coordinating sphere of the active site. Interestingly, the effects of the same pendant group inside different complexes with different backbones on the catalytic activity of catalysts may be apparently different, so far as to involve the transformation of the major and minor influencing-factors. Moreover, the effect of the center metal on the reactivity of catalyst has been evaluated, and it is found that the ratio of charge and radius of the metal is one of the important factors.The micellar system has firstly been introduced to the hydrolytic cleavage of HPNP as a RNA model substrate. Initially, the hydrolytic cleavage of HPNP induced by an imidazole derivative Zn(II) complex has been investigated in Gemini 16-2-16 micellar solution and traditional CTAB micelles, respectively. The results obtained show that the rate of HPNP catalytic cleavage in Gemini 16-2-16 micelles exhibited about 2.5-fold kinetic advantage compared to that in CTAB system. Furthermore, it is found that the addition of cationic surfactants in the homogenous system containing catalyst and HPNP with good water-solubility dramatically accelerated the hydrolytic cleavage of HPNP. A "sandwich absorptive mode (micelle-HPNP-catalyst)" is proposed to explain the interesting results. In general, to accelerate the mass transfer process in a heterogeneous reaction, surfactants are added to the catalytic system, in which the substrate and catalyst distributed in different pseudo-phases. Thus, our study extends the usage of cationic surfactants.更多还原