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1.
利用三脚架配体-钴(Ⅱ)配合物作为催化剂进行了水解催化4-硝基苯酚醋酸酯(NA)的研究.在pH7.5-9.4范围生成钴(Ⅱ)金属配合物(配体∶钴离子=1∶3),在25℃和不同的pH值条件下(pH7.5-9.4),通过观察4-硝基苯酚的释放速率研究了钴配合物催化4-硝基苯酚醋酸酯的水解反应动力学.结果表明,钴(Ⅱ)配合物可以作为有效的亲核试剂催化NA酯水解,水解速率v=(koMbsL[ML] kOH[OH-] k0)[NA],二级水解速率常数为0.197 mol-1.dm3.s-1.  相似文献   

2.
研究了2,9-二(n-5,’8’-二氮杂壬烷基)-1,10-邻菲罗啉合铜(Ⅱ)配合物作为水解酶模拟物催化4-硝基苯酚醋酸酯(NA)水解反应动力学.在pH为7.4~9.2范围内配体与铜(Ⅱ)形成了1∶1(配体∶铜离子)配合物.结果表明,催化水解速率对NA及配合物浓度皆呈一级反应,其水解速率方程为v=koTbs[NA]=(koMbsL[ML]T kOH-[OH-] k0 i)[NA],二级反应速率常数kMLH-1在一定范围内随pH值的增加而增加;kMLH-1的最大值和kOH分别为0.131,18.22 mol-1.dm3.s-1,k0为NA的溶剂水解常数,k0=1.26×10-6s-1((25.0±0.1)℃,I=0.10 mol/L KNO3,0.020 mol/L Tris缓冲溶液);kMLH-1值显示该配合物催化活性较高,表明Cu(Ⅱ)配合物中的Cu…OH-是有效的亲核试剂,对底物NA酯的水解有较好的催化作用.同时,依据实验结果提出了催化反应的机理.  相似文献   

3.
用分光光度法研究了一种长链取代吡啶类配体(L)及其铜(Ⅱ)和锌(Ⅱ)的配合物在25℃及pH6.5-8.5的条件下,在CTAB胶束缓冲溶液中催化PNPP和PNPA水解的反应。结果表明,活化的配体羟基可以作为反应过程中有效的亲核物种,锌(Ⅱ)配合物比铜(Ⅱ)配合物能更有效地催化PNPP的水解,这种情况可以解释为锌(Ⅱ)配合物中活化的配体羟基具有更强的亲核进攻能力。作者推导了包括配体、金属离子和底物在内的金属配合物催化PNPP水解的三元复合物动力学模型,提出了金属配合物催化PNPA水解的双分子催化动力学模型,并得到了相应的热力学及动力学参数,实验结果也证明了这些模型的合理性。  相似文献   

4.
为研究三爪结构配体稀土配合物的组成、可能的配位状态及与DNA的作用方式,合成了新型三爪结构配体——三[(5-亚甲基-8-羟基喹啉)氨基乙基]胺及其5种稀土配合物.用元素分析、摩尔电导率、IR光谱和TG-DTA方法分析了该类化合物的组成和结构;通过UV光谱和荧光光谱研究了配合物与CT DNA的作用方式.结果表明,该系列配合物的组成为[REL(NO3)2]NO3.4 H2O(RE=Eu,Tb,Nd,La,Ce),其中2个硝酸根以双齿形式与金属离子配位,总配位数为10;配合物与CT DNA之间存在着插入作用.  相似文献   

5.
采用溶剂热合成方法,合成了一个新颖的一维锌(Ⅱ)配位聚合物[Zn(absa)(pcih)](CH3OH)(1)(Habsa=4-氨基酸苯磺酸,Hpcih=2-吡啶甲醛异烟酰腙),并研究了配体Hpcih及锌(Ⅱ)配合物的生物抑菌能力以及促进玉米幼苗生长的生物活性作用.结果表明,Hpcih及[Zn(absa)(pcih)](CH3OH)在较低浓度时对金黄色葡萄球菌、大肠杆菌和枯草杆芽孢杆菌有较强的抑菌效果,并且对植物玉米幼苗具有一定的促生长作用.  相似文献   

6.
双核Zn(Ⅱ)配合物的合成与量子化学计算   总被引:2,自引:1,他引:2  
合成了二(2-苯并咪唑亚甲基)胺(N3)和其副产物[2,5-二(苯并咪唑亚甲基)环二肽](BBD)的混合配体与Zn(Ⅱ)的双核超氧化物歧化酶模型化合物。对化合物[N3ZnBBDZnN3(DMF)2].4(ClO4).2(DMF)(C70H90N22O24Cl4Zn2,A)进行了元素分析,紫外和红外表征;利用测得的晶体结构坐标,用Guassian98程序在HF/LANL2DZ基组对桥连双锌配合物进行了量子化学计算,得到原子轨道贡献和原子净电荷布居信息。  相似文献   

7.
以二茂铁乙酸钠为配体,4,4’-bpy为辅助桥联配体,合成了一个新的一维链状配位聚合物[Pb(η^2-OOCCH2Fe)2(4,4'-bpy)]n(Fc=二茂铁),并用X-射线单晶结构分析法测定了其晶体结构。对标题配合物以及二茂铁乙酸钠配体的荧光性质研究结果表明:该配合物的荧光性能主要取决于配体的性质。  相似文献   

8.
合成了[N-(2-脱氧-β-D-吡喃葡糖-2-水杨醛胺)]M(Ⅱ)单核金属配合物(M=Cu,Zn,Co,Ni),使用分光光度法研究了该单核的在CTAB胶束溶液中催化PNPP水解反应动力学,用单核配合物金属胶束的三元复合动力学模型对实验结果进行了讨论。实验结果表明:这类配合物在CTAB胶束溶液中形成金属胶束后,催化水解的能力明显增强,在中性或偏碱性环境中对PNPP的水解具有很好的催化活性,且金属配合物催化水解的速率常数其大小顺序为Zn(Ⅱ),Cu(Ⅱ),Co(Ⅱ),Ni(Ⅱ)。  相似文献   

9.
以5-氯-水杨醛双缩(1R,2R)-环己二胺(CSA-DMC)为原料制备了手性[Mn(csal-R,R-chxn)]Cl配合物,测定了手性配体CSA-DMC的荧光光谱,研究了手性配合物[Mn(csal-R,R-chxn)]Cl的CD光谱及催化苯乙烯不对称环氧化反应的催化性能.结果表明:手性配体CSA-DMC的荧光发射峰处于517 nm;利用激子裂分方法和d-d跃迁关联法推测了手性席夫碱配合物[Mn(csal-R,R-chxn)]Cl绝对构型为(R)Δλ构型;最适宜反应条件下,催化苯乙烯的不对称环氧化反应的转化率为74.9%,催化剂选择性为67.6%,对映体过量百分率(e.e.)为12.3%  相似文献   

10.
利用初始配合物[Cu(CH3N)2(PPh3)]BF4分别与多吡啶配体反应,成功地合成了2个新颖的Cu(Ⅰ)-多吡啶配位化合物:[Cu(CH3N)2(PPh3)]BF4(1)和[Cu(CH3N)2(PPh3)]BF4(2),并对配合物进行了红外光谱、元素分析、X射线单晶衍射表征,以及紫外光谱、荧光光谱光谱性质的初步研究。  相似文献   

11.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

12.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

13.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

14.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

15.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

16.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

17.
18.
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.  相似文献   

19.
R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).  相似文献   

20.
The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.  相似文献   

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