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1.
本文报道了一类长链烷氧取代金属卟啉化合物3的合成.研究了由化合物3与表面活性剂:十二烷基三甲基溴化铵所形成的混合胶束体系作为仿细胞色素P-450加氧酶模拟物对苯乙烯环氧化的催化活性.结果表明:在胶束体系中长链烷氧取代金属卟啉的催化效率优于对称四甲苯基金属卟啉,由此证实:混合胶束中,疏水内核提供的模拟酶的疏水微环境,在苯乙烯环氧化反应中起着重要作用.  相似文献   

2.
疏水性金属卟啉的合成及催化性能研究   总被引:8,自引:0,他引:8  
本文合成了一类带疏水性长链的对称卟啉及其金属配合物, 研究了该类金属卟啉在CH2Cl2/H2O两相体系中催化苯乙烯的环氧化反应性能。通过以上研究, 发现催化反应体系中水相PH值对烯烃环氧化反应有很大影响; 改变金属卟啉的疏水性对催化反应影响不大; 具不同中心金属离子的金属卟啉有不同的催化活性, 催化活性顺序为:Mn>Co>Ni>Cu。  相似文献   

3.
本文研究了通过长链烷氧甲基取代三甘醇(2)的环化反应合成一系列长链烷氧甲基-15-冠-5 (3) .在25℃, 35℃,45℃下测定了烷氧甲基冠醚化合物和(2)的表面张力,CMC及γ~C~M~C.结果显示,随着疏水链碳原子数的增加,CMC值减小,疏水链的碳原子数大于8的两亲分子在水溶液中可形成胶束.  相似文献   

4.
长链烷氧基取代金属卟啉/H_2O_2体系催化烯烃环氧化反应研究肖友发,游劲松,余孝其,虞小华,蓝仲薇(四川大学化学系成都610064)关键词长链烷氧基金属卟啉,过氧化氢,烯烃,环氧化反应具有疏水结合部位的金属卟啉,如甾体一金属卟啉[1]、环糊精一金属卟...  相似文献   

5.
用表面张力测定法研究了长链烷氧甲基取代三甘醇及长链烷氧甲基取代冠醚的表面活性.结果表明,当侧链碳原子数大于8的双亲分子,在水溶液中一般均可形成胶束,而且随着碳原子数的增加,双亲分子在水溶液中的临界胶束浓度(CMC)值减小,且每增加两个碳原子,其CMC值减小约10倍.在每一温度下,同系物CMC的对数值与疏水链碳原子数之间呈线性关系,求出了回归方程。探讨了NaCl对上述两种化合物表面活性的影响.  相似文献   

6.
杯[6]芳烃-双锰卟啉催化苯乙烯环氧化反应的动力学   总被引:2,自引:0,他引:2  
研究了杯[6]芳烃-双锰卟啉仿P450酶模型化合物对苯乙烯环氧化反应的催化性能,考察了催化剂浓度、底物浓度、氧源浓度及加入方式等对催化反应的影响,结果表明,由于具有较大疏水孔穴的杯[6]芳烃的引入,使金属卟啉的催化性能得以较大的提高,且反应遵从Michaetis-menten规律,在实验基础上,本文提出了一种可能的反应机理。  相似文献   

7.
金属卟啉催化下环己烷羟基化反应的Hammett关系   总被引:1,自引:1,他引:1  
合成了40个卟啉环上具有不同取代基的单铁、锰卟啉和μ-氧桥连双铁、锰卟啉、研究了这些金属卟啉模拟细胞色素P-450单充氧酶在温和条件下催化环己烷羟基化的反应。首次用线性自由能关系对金属卟啉仿生催化反应和金属卟啉自氧人反应进行相关分析,获得一 些新的结果和规律。在此基础上,对金属卟啉仿生催化反应的可能机理进行了探讨。  相似文献   

8.
采用Monte Carlo模拟方法研究了疏水-亲水-疏水(H-P-H)型ABC三嵌段共聚物在B嵌段的选择性溶剂中的自组装行为. 模拟结果表明, 通过调节A嵌段和C嵌段的疏水性和二者之间的不相容性, 体系中可以形成多种形貌各异的胶束. 根据胶束中疏水核结构的特点, 这些胶束大体上可以被分为多核型胶束和多间隔型胶束两种类型. 通过增强疏水嵌段的疏水性或降低A嵌段和C嵌段间的不相容性, H-P-H型ABC三嵌段共聚物胶束能够发生从多核型胶束向多间隔型胶束的转变. 进一步分析胶束中聚合物的链构象等微观结构信息发现, A嵌段和C嵌段间的排斥作用和疏水作用之间存在竞争关系, 而这种竞争关系是影响体系中形成多核型胶束还是多间隔型胶束的决定性因素.  相似文献   

9.
各种金属卟啉催化环已烷的羟化作用   总被引:6,自引:0,他引:6  
金属卟啉、分子氧、抗坏血酸和底物构成细胞色素P450摸拟体系,实现了在常温常压下环已烷选择氧化为环已醇和环已酮,产品环已醇和环已酮是与金属卟啉周围取代基的类型密切相关,研究了中心金属离子,轴向配体,底物和催化剂的比例,以及pH对反应的影响,最后提出了金属卟啉活化分子氧的反应机理.  相似文献   

10.
研究了杯[6]芳烃-双金属卟啉仿P450酶模型化合物对环己烯环氧化反应的催化性能.考察了温度、氧源浓度、催化剂浓度、底物浓度、卟啉环中位苯基上取代基、溶剂等因素对反应的影响.结果表明,杯[6]芳烃-双金属卟啉的催化性能优于相应的简单金属卟啉单体,且反应遵从Michaelis-Menten规律.这是由于作为疏水结合部位的杯[6]芳烃大环的引入,导致多部位识别协同催化,从而极大地提高了金属卟啉的催化性能.  相似文献   

11.
The model compounds of androgenic steroid-bismetallopor-phyrins 3a-3d and androgenic monometalloporphyrins 2a-2d have been synthesized. Catalytic study in two-phase condition on epoxidation of styrene under the catalysis of model catalysts shows (hat the catalytic performances of steriod-bismet-alloporphyrin is superior to steroid- metalloporphyrin and the corresponding simple metalloporphyrin. The excellent catalytic property of steriod-bismetallopotphyrin can be rationalized as the hydrophobic action of steroid framework and the cooperative action of two metalloporphyrins in catalysis.  相似文献   

12.
本文综述了近几年来手性金属卟啉配合物在主客体化学、立体催化及光电化学领域的性能研究成果。分析了在主客体化学中手性卟啉作为分子识别反应主体所具有的结构特征;介绍了模拟生物大分子的功能时手性卟啉所反映出的识别机制;评述了手性卟啉对苯乙烯及其衍生物的环丙烷化、羟基化及氨化等催化反应中所展示出的对映选择性和催化稳定性;概括了手性卟啉配合物在模拟植物光合成反应和制作新型光学材料方面所具有的光电性能。最后总结了手性卟啉研究成果的应用范围,并展望了手性卟啉在催化氧化方面的研究和发展方向。  相似文献   

13.
Construction of artificial oxygen carriers by use of iron or cobalt complexes bound to synthetic polymers was attempted. Radical copolymerization of porphyrin vinyl monomers with styrene gave the metalloporphyrins covalently bonded to a polymer chain at low concentration. For these metalloporphyrin polymers, irreversible oxidation via dimerization was prevented in aprotic solvents and reversible oxygenation was observed. The chemical environment around the oxygen-binding site was presumed to play an important role on the stability of oxygenated complex as in the case of the tetraamide groups on the porphyrin plane. When ethylenebis(salicylideniminato)cobalt chelate coordinated to a polymer-ligand, it formed a stable oxygenated complex at room temperature. Rotational motion of the chelate was decreased markedly by the polymer chain to enhance the coordinate bond between the metal ion and the bound oxygen molecule. Furthermore, the iron porphyrin with bulky substituents was oxygenated even in homogeneous aqueous solutions by combining it with the rigid, hydrophobic domain of a water-soluble block copolymer.  相似文献   

14.
Encapsulation of chiral ruthenium porphyrin [RuII(D4-Por*)CO] in modified mesoporous silica supports such as MCM-41 and MCM-48 achieves active catalysts for asymmetric epoxidation of alkenes by 2,6-dichloropyridine N-oxide and intramolecular cyclopropanation, which is the first example of chiral metalloporphyrin supported on ordered molecular sieves.  相似文献   

15.
Self‐organized organic nanoparticles (ONP) are adaptive to the environmental reaction conditions. ONP of fluorous alkyl iron(III) porphyrin catalytically oxidize cyclohexene to the allylic oxidation products. In contrast, the solvated metalloporphyrin yields both allylic oxidation and epoxidation products. The ONP system facilitates a greener reaction because about 89% reaction medium is water, molecular oxygen is used in place of synthetic oxidants, and the ambient reaction conditions used require less energy. The enhanced catalytic activity of these ONP is unexpected because the metalloporphyrins in the nanoaggregates are in the close proximity and the TON should diminish by self‐oxidative degradation. The fluorous alkyl chain stabilizes the ONP toward self‐oxidative degradation.  相似文献   

16.
Metalloporphyrins and crown ether groups were simultaneously supported on chloromethylated polystyrene resin to produce a series of polymer-supported catalysts. The synthesis of these catalysts has been studied. The influence of pH, concentrations of NaOCl and phase transfer catalysts on the epoxidation of styrene catalyzed by these catalysts has also been investigated. The experimental results show that manganese(III) porphyrin bound to chloromethylated polystyrene which bears crown ether groups is effective catalysts for the epoxidation of styrene by sodium hypochlorite. The introduction of crown ether groups increases the catalytic efficiency of supported metalloporphyrins. The kinetics of epoxidation catalyzed by supported manganese(III) porphyrins obeys Michaelis-Menten equation—the characteristic of enzyme-driven reaction.  相似文献   

17.
The reaction of optically active Halterman porphyrin with sulfuric acid (95%) provided the expected water-soluble para-tetrasulfonated porphyrin in 82% yield. The metalloporphyrin complexes were prepared by metal insertion (iron) or direct sulfonation of the chiral ruthenium porphyrin. The asymmetric addition of diazoacetate to styrene to give optically active trans cyclopropyl ester (ee up to 86%) was carried out in water by using chiral iron or ruthenium porphyrins with a possible reuse due to the high solubility and stability in aqueous solution.  相似文献   

18.
离子液体体系中离子型锰卟啉对苯乙烯的催化氧化   总被引:2,自引:0,他引:2  
以单氧给体乙酰碘苯[PhI(OAc)2]为氧源, 在无需轴向配体和有机溶剂的参与下, 离子型锰卟啉[MnⅢ(BF4)T(N-Me-4-Py)P][BF4]4和离子液体 [BMIM]BF4组成的多元离子液体体系, 在温和的反应条件下对苯乙烯的催化氧化表现出较高的活性(87%)和环氧苯乙烷选择性(90%), 并且有较好的底物普适性. 构筑的锰卟啉多元离子液体体系可以一定程度上抑制卟啉聚合和氧化降解等反应.  相似文献   

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