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1.
近年来,人们对锰配合物的研究引起极大兴趣,这主要归因于锰的配合物有其生物功能.生物体内的过氧氢化酶、过氧歧化酶和放氧复合物,这3种酶的作用都涉及锰(Ⅱ)离子,锰离子参与了生物体内的氧化还原反应,是绿色植物的第二类光合系统的活性中心[1].  相似文献   

2.
采用快速混合停流技术,在实际反应条件下,考察了五氟代锰卟啉配合物Mn~Ⅲ(TFPP)C1与两种单氧给体亚碘酰苯PhIO和过氧苯甲酸m-CPBA构建的细胞色素P-450模拟酶体系催化活性物种的生成及催化烯烃环氧化过程.在氧给体PhIO作用下,Mn~Ⅲ(TFPP)C1生成了高价锰氧卟啉配合物和双核μ-氧锰卟啉配合物,具有高的催化环氧化活性和催化剂稳定性.而在氧给体m-CPBA作用下,Mn~Ⅲ(TFPP)C1则生成了一种较稳定物种,以致催化活性较低。  相似文献   

3.
修饰剂结构对桥氧双核锰2,2'-联吡啶配合物电化学的影响吴丛笑,郑军伟,陆天虹(中国科学院长春应用化学研究所电分析化学开放实验室,长春,130022)关键词桥氧双核锰2,2'-联吡啶配合物,烟酸,异烟酸,2-羧酸吡啶锰酶在生物体系中作为一类重要的氧化...  相似文献   

4.
铜是生物体内重要的微量元素,广泛地存在于动物、植物和微生物体内,并且通常与生物配体形成稳定的混配配合物,在生命过程中(酶的催化、物质的储存和运送以及铜离子的转运等)起着极其重要的作用,因此研究铜生物配体配合物对探索铜在生物体内的作用机制有重要意义[1~3].  相似文献   

5.
配位化学中的直线自由能关系(XIX)   总被引:2,自引:0,他引:2  
前文[1]曾报导了侧基二氧四胺大环配体的合成及表征.与普通配合物相比,大环多胺配合物具有较高的稳定性及惰性和奇特的空间构型,其过渡金属配合物具有特殊的性质和用途,如作酶的模型、氧的载体等.铜(Ⅱ)配合物可作超氧歧化酶(SOD)的模型,超氧离子是人体内的氧代谢产物,它在体内过量积累会引起多种疾病,超氧歧化酶对超氧离子起催化歧化作用,以维持机体的正常运行间,故这种大环多胺Cu(Ⅱ)配合物具有重要的生物功能及广阔的应用前景.本文研究了四种带侧基二氧四胺大环配体-5-取代邻菲罗啉(5-Xphen;L1)铜(Ⅱ)三元配合…  相似文献   

6.
生物体系中含锰金属酶模型配合物的结构研究进展   总被引:2,自引:0,他引:2  
锰作为生命体系中必需的一种微量元素,主要是以锰酶的形式存在,它构成了生物体内许多酶的活性中心。这些活性中心在生物体中扮演着许多重要角色,如氧化还原、电子传递、路易斯酸催化等。基于锰在生命体系中的重要性,文章从结构方面综述了近几年来国内外关于生命体系中含锰金属酶模型配合物结构的研究进展,其中主要阐述了多核,即双核,三核和四核锰模型配合物的结构特征。  相似文献   

7.
在很多生物代谢过程中,微量元素W起着关键作用,W与生物大分子结合形成具有特异功能的钨氧转移酶。1983年从热醋酸菌中提取了第一种钨酶,即甲酸脱氢酶,目前从生物体内提取的钨酶种类已达十二种之多,并发现钨氧转移酶与钼氧转移酶的活性结构因子呈相近性[1]。随着钨酶在生物体内的作用逐步得到重视,及其模拟的功能配合物在探究钨酶的生理活性和催化机理研究中所作的突出贡献,使钨氧转移酶活性结构因子的仿生合成、生理活性以及催化机理研究成为研究热点[2 ̄14]。根据报道显示,单分子的钨氧模拟配合物中W的价态只有WⅣ、WⅥ两种,且形成一个电…  相似文献   

8.
锰在某些生物的氧化还原活性部位起着重要的作用. 绿色植物光系统Ⅱ(PSⅡ)中的氧释放配合物(OEC)、含锰过氧化氢酶(Mn Catalase)、含锰超氧化物歧化酶(MnSOD)、含锰核糖核苷酸还原酶(Mn RR)等活性部位存在着双核或多核锰的配合物[1~3]. 因此, 模拟合成不同氧化态的、不同类型配体和不同核数锰的配合物, 研究其结构和光谱等性质, 对揭示生物体中锰酶的催化氧化还原过程将有重要意义. 混合价Mn(Ⅲ, Ⅳ)配合物的研究对于揭示PSⅡ中两分子H2O氧化为O2的机理具有重要意义[2,4]. 这类配合物的研究已有一些报道[5~10], 邻菲咯啉(Phen)作为配体形成的配合物[(Phen)2Mn\5(μ-O)2Mn(Phen)2](PF6)3*CH3CN的研究虽有报道[11], 但其晶体中两个锰离子配位环境几乎相同. 本文用新方法合成了双核锰配合物(该法容易得到单晶)并进行了表征.  相似文献   

9.
细胞色素P-450在生物体内温和条件下活化分子氧,选择地催化氧化很不活泼的碳氢化合物。铬(Ⅲ)卟啉配合物在温和条件下以亚碘酰苯或过氧羧酸等为氧化剂可选择性地催化氧化碳氢化合物,是细胞色素P-450的很好的模型化合物,但目前得到的铬(Ⅲ)卟啉配合物为数尚少。本文在三氯甲烷中用氧化-还原法从一氯四苯基卟啉合铬(Ⅲ)(配合物Ⅰ)合成了迭氮基吡啶四苯基卟啉合铬(Ⅱ)(配合物Ⅱ),培养了配合物Ⅱ的单晶,x-射线四圆衍射法测定了其晶体和分子结构。这是第一个得到的三价铬四苯基卟啉的分子结构。  相似文献   

10.
锰的配位化学由于其生物功能,而愈来愈引起人们的广泛兴趣。在某些生物酶中,锰的配位环境多为咪唑的氮和羧基及水分子的氧原子配位[1,2]。由于Schif碱以氮原子和氧原子配位,与生物环境接近,在模型配合物研究方面,以多齿Schif碱为配体的锰的配合物,特...  相似文献   

11.
12.
We review our research on the synthesis and study of the physical and biological properties of furyl- and thienylgermatranes and -silatranes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 725–732, June, 1992.  相似文献   

13.
The use of the insect cell/baculovirus expression system for producing recombinant proteins of bacterial, plant, insect, and mammalian origin has become widespread. The popularity of this eukaryotic expression system is due to many factors, including (1) potentially high protein expression levels, (2) ease and speed of genetic engineering, (3) ability to accommodate large DNA inserts, (4) protein processing similar to higher eukaryotic cells (e.g., mammalian cells), and (5) ease of insect cell growth (e.g., suspension growth). The following review of the literature discusses two engineering aspects of recombinant protein synthesis by insect cell cultures: bioreactor scale-up and insect cell line selection. Following this review patent abstracts and additional literature pertaining to expression of recombinant proteins in insect cell culture are listed.  相似文献   

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16.
The aromaticity and antiaromaticity of the ground state (S 0), lowest triplet state (T 1), and first singlet excited state (S 1) of benzene, and the ground states (S 0), lowest triplet states (T 1), and the first and second singlet excited states (S 1 and S 2) of square and rectangular cyclobutadiene are assessed using various magnetic criteria including nucleus-independent chemical shifts (NICS), proton shieldings, and magnetic susceptibilities calculated using complete-active-space self-consistent field (CASSCF) wave functions constructed from gauge-including atomic orbitals (GIAOs). These magnetic criteria strongly suggest that, in contrast to the well-known aromaticity of the S 0 state of benzene, the T 1 and S 1 states of this molecule are antiaromatic. In square cyclobutadiene, which is shown to be considerably more antiaromatic than rectangular cyclobutadiene, the magnetic properties of the T 1 and S 1 states allow these to be classified as aromatic. According to the computed magnetic criteria, the T 1 state of rectangular cyclobutadiene is still aromatic, but the S 1 state is antiaromatic, just as the S 2 state of square cyclobutadiene; the S 2 state of rectangular cyclobutadiene is nonaromatic. The results demonstrate that the well-known "triplet aromaticity" of cyclic conjugated hydrocarbons represents a particular case of a broader concept of excited-state aromaticity and antiaromaticity. It is shown that while electronic excitation may lead to increased nuclear shieldings in certain low-lying electronic states, in general its main effect can be expected to be nuclear deshielding, which can be substantial for heavier nuclei.  相似文献   

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18.
多环芳二酐型聚酯亚胺膜的透气性能李悦生,丁孟贤,徐纪平(浙江大学高分子科学与工程研究所,杭州,310027)(中国科学院长春应用化学研究所)关键词聚醚酰亚胺,聚酯酰亚胺,膜,透气性通常的聚酰亚胺加工性能较差,在芳环二酐的苯环间引入醚键等柔性基团后,其...  相似文献   

19.
A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg?1, the maximum residue level of European Union for quizalofop-p-ethyl).  相似文献   

20.
The P-anilino-P-chalcogeno(imino)diazasilaphosphetidines [Me(2)Si(mu-N(t)Bu)(2)P=E(NHPh)] (E = O (3), S (4), Se (5), N-p-tolyl (6)) were synthesized by oxidizing the P-anilinodiazasilaphosphetidine [Me(2)Si(N(t)Bu)(2)P(NHPh)] (2) with cumene hydroperoxide, sulfur, selenium, and p-tolyl azide, respectively. The lithium salt of 4 reacted with thallium monochloride to produce ([Me(2)Si(mu-N(t)Bu)(2)P=S(NPh)-kappaN-kappaS]Tl)(7), which features a two-coordinate thallium atom. Treatment of 4-6 with AlMe(3) gave the monoligand dimethylaluminum complexes ([Me(2)Si(mu-N(t)Bu)(2)P=E(NPh)-kappaN-kappaE]AlMe(2)) (E = S (8), Se (9), N-p-tolyl (10)), respectively. In these complexes the aluminum atom is tetrahedrally coordinated by one chelating ligand and two methyl groups, as a single-crystal X-ray analysis of 8 showed. A 2 equiv amount of 4-6 reacted with diethylzinc to produce the homoleptic diligand complexes ([Me(2)Si(mu-N(t)Bu)(2)P=E(NPh)-kappaN-kappaE](2)Zn)(E = S (11), Se (12), N-p-tolyl (13)). A crystal-structure analysis of 11 revealed a linear tetraspirocycle with a tetrahedrally coordinated, central zinc atom.  相似文献   

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