Schiff碱Co(Ⅱ)配合物在胶束中催化BNPP水解

合成和表征了两种对称的带冠醚环或吗啉环的Schiff碱Co(Ⅱ)配合物,将此配合物和表面活性剂形成的金属胶束,用于模拟水解金属酶催化BNPP水解。通过分析反应体系的特性吸收光谱,提出了BNPP催化水解反应的机理,据此建立了金属胶束催化BNPP水解的动力学数学模型。本文还讨论了配合物结构、反应体系温度以及胶束对催化BNPP水解的影响。     

冠醚化Schiff 碱配合物金属胶束催化BNPP水解动力学

研究了两种新的冠醚化Schiff 碱过渡金属配合物与表面活性剂Brij35(聚氧乙烯(23)十二烷基醚)形成的金属胶束对BNPP（对硝基苯酚磷酸二酯）的催化水解反应. 探讨了催化反应机理, 建立了一种金属胶束催化BNPP水解的动力学数学模型; 计算了模拟酶催化反应的相关参数和表观活化能. 结果表明, 此类金属胶束作为模拟水解金属酶对BNPP水解反应表现出良好的催化活性.     

一种活性磷酸酯的分子内亲核取代反应动力学研究

合成和表征了大环过渡金属配合物NiL(L:高氯酸-5,7,7,12,14,14-六甲基-1,4,8,11-四氮杂环十四烷)。配合物NiL与表面活性剂组成的金属胶束作为模拟水解金属酶用于催化BNPP水解。提出了BNPP催化水解的机理;建立了用于计算动力学常数的动力学模型;计算了相关的动力学和热力学常数。结果表明,这种金属胶束表现出较高的催化活性;BNPP催化水解反应是分子内亲核取代反应;所提出的机理和建立的动力学模型是合理的。     

草酰胺桥联双核铜配合物金属胶束催化BNPP水解的动力学和机理研究

合成了草酰胺桥联双核铜配合物(RCu2(H2O)2(ClO4)2)(A)和(R′Cu2(H2O)2(ClO4)2)(B)。研究了A、B与表面活性剂LSS和CTAB形成的金属胶束催化二(对硝基苯酚)磷酸二酯(BNPP)水解机理,建立了动力学模型。结果表明在25℃、pH=7的条件下,该类金属胶束对BNPP水解有催化作用,BNPP催化水解速率比其自水解速率提高1×106倍,这是由于双核铜配合物中两个铜离子的协同作用、表面活性剂胶束的浓聚效应和pH效应所致。因此含双水的草酰胺桥联双核铜配合物金属胶束是一较好的磷酸二酯水解酶的模拟模型。     

杂氮冠醚化Schiff碱钴(Ⅱ)配合物模拟磷酸二酯水解酶的研究

含杂氮冠醚的Schiff碱过渡金属配合物作为模拟水解酶被用于催化BNPP水解，讨论了两种杂氮冠醚化单Schiff碱钴(Ⅱ)配合物催化BNPP水解的动力学和机理，分析了反应体系的特征光谱变化。提出了配合物催化BNPP水解的动力学数学模型，结果表明，在反应过程中形成中间物种的假设是合理的；随着缓冲溶液pH的增大，两种配合物催化BNPP水解速率提高；两种配合物在催化BNPP水解中表现出好的催化活性。     

带羧基支链的四氮杂环铈配合物催化磷酸酯水解的研究

合成和表征了一种大环配体5,5,7,12,12,14-六甲基-1,4,8,11-四氮杂环十四烷-N/-乙酸(L),研究了金属铈离子和配体组成的体系催化对硝基苯酚磷酸二酯(BNPP)水解的动力学.结果表明:该体系在催化对硝基苯酚磷酸二酯(BNPP)水解方面表现出高的催化活性和稳定性,以及好的水溶性.通过对特征光谱和化学计算的分析表明,催化活性物种是金属铈和配体组成的配合物.基于光谱分析的结果,提出了BNPP催化水解的机理及得到研究结果的证明.     

草酰胺桥联双核铜配合物金属胶束催化PNPA水解反应动力学

研究了草酰胺桥联双核铜配合物和不同表面活性剂胶束组成的金属胶束催化PNPA水解的动力学特征。结果表明：金属胶束催化PNPA水解为双分子反应；不同配体结构的配合物的催化活性不同；三种不同类型表面活性剂胶束对催化PNPA水解的影响也不同。     

环四烯四胺-Ce（Ⅲ）金属配合物催化水解双（对硝基苯酚）磷酸酯

研究金属离子在金属酶中的作用机理以及用双核金属配合物模拟酶的催化中心和协同作用的研究倍受关注。镧系金属离子由于其特殊的化学结构对磷酸酯的水解有促进作用，本文研究发现环四烯四胺-Ce(Ⅲ)金属配合物对BNPP有显著的催化水解作用。     

胶束溶液中高氯酸二水(四胺)合钴(Ⅲ)配合物催化磷酸二酯水解的研究

本文合成了疏水性高氯酸二水（四胺）合钴（Ⅲ）配合物，研究了它与非离子表面活性剂Brij35形成的金属2胶束催化二（对硝基苯酚）磷酸二酯水解的动力学及其机理。结果表明此金属胶束对磷酸二酯水解的速率大约提高10^4倍，这主要是由于表面活性剂胶束的pH效应和浓聚效应所致，暗示着顺式二水类配合物形成的金属胶束是一个潜在的磷酸二酯水解剪切的催化剂。     

La(Ⅲ)配合物催化磷酸酯水解动力学研究

实验合成了单核镧和异双核的铜镧配合物，并研究了35℃时在50%二甲亚砜水溶液中催化磷酸二酯（bis(p-nitropheny1 phosphate)(BNPP))水解的动力学。结果表明，这两种配合物均能有效地催化BNPP的水解，得到的pH~速率曲线图呈钟形；但不同的配合物表现出不同的催化活性，单核的La(Ⅲ)配合物比异双核的Cu(Ⅱ)La(Ⅱ)配合物能更有效地催化BNPP的水解，这很可能是由于底物对催化剂的空间需要不同造成的。本文运用相应的动力学模型处理得到了相关的动力学和热学参数。     

阳离子表面活性剂金属胶束作为模拟磷酸酯水解酶的研究

在模拟水解酶的研究中,模拟模型中配体的功能已经受到普遍重视,冠醚是外腔疏水而内腔亲水的物质,因此已被用作模拟水解酶模型中的配体。这些模型可以分为两类,一是金属离子镶嵌在冠醚环中所形成的穴状配合物模型,二是以冠醚基作为支链的冠醚化Schiff碱配合物。穴状配合物模型作为模拟水解酶用于催化磷酸酯的研究已经取得了一定的进展。     

Function of the Metallomicelle from an Aza-Crown Ether Complex with an Acetamide Branch as a Highly Potent Promoter of Phosphate Diester Hydrolytic Cleavage

This study reports the synthesis method of a new aza-crown ether with an acetamide branch ligand, 2-(1,10-dioxa-4,7,13,16-tetraaza-cyclooctadec-4-yl)-acetamide (L), and determines the chemical composition of the cerium complex containing the aza-crown ether ligand by a new fluorescence spectrophotometric method. In the report, the cerium complex and its metallomicellar systems were used as catalysts in the hydrolysis of bis(4-nitrophenyl)phosphate ester (BNPP), and their catalytic activity was studied by the comparative method. The interaction between the metallomicelle and BNPP was proved by the fluorescence spectrum. The catalytic rate of BNPP hydrolysis was measured kinetically using the UV-Vis spectrophotometric method. The results indicated that the metallomicellar system of the anionic surfactant exhibited excellent catalytic function and relatively higher catalytic activity than that of the complex solution, the metallomicelle of nonionic and cationic surfactants, and the micelle provided an effective catalytic environment for the catalytic reaction. The experimental results also showed that the best acidity for the metallomicelle catalysis is pH 8.0, and the mono-hydroxy complex may be the real active species uaed as a catalyst in BNPP catalytic hydrolysis. The reaction mechanism was proposed on the basis of the research results.     

苯并氮杂冠醚-15-冠-5 Schiff碱钴(Ⅱ)配合物在胶束中催化BNPP水解研究

在催化磷酸二酯水解的模拟酶模型中,配合物配体结构扮演了非常重要的角色[1-2]。由于冠醚环具有主客体识别功能,在酶学理论中把它作为模拟酶的第一代生物有机体。镶嵌有过渡金属离子的冠醚配合物对催化磷酸二酯水解具有很好的活性[3];Schiff碱过渡金属离子配合物对催化磷酸二酯水解也具有很好的活性[4]。因此,冠醚Schiff碱过渡金属离子配合物对催化磷酸二酯水解也应具有很好的活性,这已有所报道[5]。但冠醚结构和过渡金属离子相同而取代基不同的配合物作为模拟酶催化磷酸二酯水解还未见报道。本文按文献设计合成了三种冠醚结构相同而取代基…     

Hydrolysis of BNPP Catalyzed by the Crowned Schiff Base Co(II) Complex Containing Benzoaza‐15‐Crown‐5 in Micellar Solution

It has been reported that three aza crowned Schiff base cobalt (II) complexes were synthesized and characterized, and the metallomicelle made up of the cobalt (II) complexes and surfactants(Brij35, CTAB, LSS), as mimic hydrolytic metalloenzyme, was used in catalytic hydrolysis of bis(4‐nitrophenyl) phosphate (BNPP). The analysis of specific absorption spectrums of the hydrolytic reaction systems indicated that key intermediates made up of BNPP and Co (II) complexes are formed in the reaction process of BNPP catalytic hydrolysis. The mechanism of BNPP catalytic hydrolysis proposed is based on the analytic result of specific absorption spectra. Based on the mechanism proposed, a kinetic mathematical model for the calculation of the kinetic parameter of BNPP catalytic hydrolysis has been established. The acid effect of reaction system, structure effect of the complexes, effect of temperature and effect of micelles on the rate of BNPP hydrolysis catalyzed by the complexes have been discussed.     

Hydrolysis of BNPP Catalyzed by the Crowned Schiff Base Co(II) Complexes in Micellar Solution

Two symmetrical double aza‐crowned Schiff base cobalt(II) complexes were synthesized and characterized, and the metallomicelle made up of the cobalt(II) complexes and surfactant, as mimic hydrolytic metalloenzyme, was used in catalytic hydrolysis of bis(4‐nitrophenyl) phosphate (BNPP). The analysis of specific absorption spectrums of the hydrolytic reaction systems indicated that key intermediates made up of BNPP and Co(II) complexes are formed in reaction processes of the BNPP catalytic hydrolysis. In this article, the mechanism of BNPP catalytic hydrolysis has been proposed based on the analytic result of specific absorption spectrum. A kinetic mathematical model, for the calculation of the kinetic parameter of BNPP catalytic hydrolysis has been established based on the mechanism proposed. The acid effect of reaction system, the structural effect of the complexes, the effect of surfactant micelles and the effect of temperature on the rate of BNPP hydrolysis catalyzed by the complexes have been discussed.     

Phosphate Diester Cleavage Promoted by the Metallomicelles of Ce(III) Complexes of Aza-Crown Ether with Different Numbers of Nitrogen Atoms

The design of artificial hydrolase has attracted extensive attention due to their scientific significance and potential application in the field of gene medicine and molecular biology. This work reports the catalytic activation of two aza-crown ether Ce(III) complexes and their metallomicelles as artificial hydrolase in bis(4-nitrophenyl) phosphate ester (BNPP) hydrolysis. The chemical composition of two complexes was determined by the fluorescence spectra and the mole ratio method for electronic absorption spectra. The bonding effect of BNPP and solubilizing effect of the complexes were proved by a method of fluorescence spectroscopy. The catalytic activity of different catalytic systems in BNPP hydrolysis was measured with UV-vis spectrophotometric method. These catalytic systems showed high catalytic activity for promoting BNPP hydrolysis at the almost physiological conditions. BNPP hydrolysis rate in these catalytic system is about 10⁷- to 10⁹-fold faster than that of the BNPP spontaneous hydrolysis in aqueous solution at the same conditions. The metallomicelle systems exhibited higher catalytic activity compared with the complex solution systems in BNPP hydrolysis, and hexadecyltrimethyl ammonium bromide micelle provides a useful catalytic environment for reaction. The acid effect of the catalytic system is ascribed to the formation of metal-bound hydroxide serving as a better kind of nucleophile.