共查询到16条相似文献,搜索用时 86 毫秒
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Calix[6] arene—bismetalloporphyrins as Enzyme Models for P450 V.Catalytic Performance in Epoxidation of Styrene 总被引:1,自引:0,他引:1
In this paper the catalytic performance of the calix[6]arene-bismetalloporphyrins in the epoxidation of styrene was studied.The influence of phase transfer catalyst,pH value,buffer agent,substrate concentration,substituent on the benzene ring of porphyrin,and the central metal ion,etc.,on the reaction rates were investigated meticulously.The results showed that the calix[6] arene-bismetalloporphyrins had a much higher catalytic activity than that of the corresponding metalloporphyrins. 相似文献
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细胞色素P—450模拟酶的快速混合停流时间分辨吸收谱研究 总被引:1,自引:1,他引:1
采用快速事停流技术,在实际反应条件下,考察了不同铁卟啉配合物Fe(Por.)Cl(Por.-TPP、TMOPP和TFPP)与单氧给体PhIO构建的模拟酶体系中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,Fe(Por.)Cl均生成了四价铁氧卟啉配合物,但Fe(TPP)Cl和Fe(TMOPP)Cl存在严重的氧化分解,而Fe(TFPP)Cl则基本未发生氧化分解,且在底物DPBD存在下 相似文献
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报道了锌-钴双金属氰化络合物(double metal cyanide complex,DMCC)催化CS2与氧化环己烯(CHO)直接共聚生成脂环族聚硫代碳酸酯的反应.傅立叶红外光谱(FTIR)及拉曼(Raman)光谱结果表明该共聚物端基为-OH和-SH结构;核磁共振(1H和13C-NMR)结果表明共聚物主链含碳酸酯-O(CO)O-链节和4种硫代碳酸酯-O(CO)S-、-S(CO)S-、-O(CS)S-和-S(CS)S-链节结构;气相色谱-质谱(GC-MS)联用结果表明产物中含有环硫环己烷及3种环状硫代碳酸酯.聚合物链结构和产物种类表明CS2/CHO共聚反应存在氧-硫原子交换反应过程. 相似文献
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Jean-Pierre Morel 《Supramolecular chemistry》2013,25(3):199-206
The formation of supramolecular complexes in water involves interactions of various types which are not always easy to identify, especially when complicated species are involved. A complete thermodynamic characterization of the binding process, which includes the enthalpies and entropies of complexation, is obviously one of the key elements in identifying the stabilizing factors and in understanding how the host and guest assemble. In order to thermodynamically characterize typical interactions of various types, we have thus undertaken a microcalorimetric study of the complexation of p-sulfonatocalixarenes with simple guests bearing different functional groups. Association constants, free energies, enthalpies and entropies for the complexation of the p-sulfonatocalix[4]arene with normal alcohols, alkylammonium, carboxylate and guanidinium ions in water, at pH 7.5 and 298.15?K, are reported. The properties for the binding of lysine and arginine, which bear similar functional groups, are also given. The comparison of the thermodynamic behaviour of these different guests allows the driving factors to be identified. This may constitute a starting point for the understanding of the recognition of more complicated guests. 相似文献
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Dimitrios P. Nikolelis Garyfallia Raftopoulou Nikos Psaroudakis Georgia‐Paraskevi Nikoleli 《Electroanalysis》2008,20(14):1574-1580
This work describes the preparation of a selective receptor for the rapid, selective and sensitive electrochemical flow injection analysis of carbofuran in foods using air stable lipid films supported on a methacrylate polymer on a glass fiber filter with incorporated artificial receptor. The selective receptor was synthesized by transformation of the ? OH groups of resorcin[4]arene receptor into phosphoryl groups. These lipid films were supported on a methylacrylate polymer (i.e., methacrylic acid was the functional monomer for the polymerization, ethylene glycol dimethacrylate was used as the crosslinker and 2,2′‐azobis‐2‐methylpropionitrile as an initiator). A minisensor device was constructed for the electrochemical flow injection analysis of toxicants based on air stabilized lipid films supported on a polymer. The device can sense the analyte in a drop (50 μL) of sample. Carbofuran was injected into flowing streams of a carrier electrolyte solution. A host‐guest complex formation between the calix[4]arene phosphoryl receptor and carbofuran takes place through hydrogen bonding. This enhances the preconcentration of carbofuran at the lipid membrane surface which in turn causes dynamic alterations of the electrostatic fields and phase structure of membranes; as a result ion current transients were obtained and the magnitude of these signals was correlated to the substrate concentration. The response times were ca. 80 s and carbofuran was determined at concentration levels of nM. The effect of potent interferences included a wide range of compounds and other insecticides. The effect of interference of proteins and lipids was also examined. The reproducibility of the method was checked by recovery experiments in fruit and vegetable samples with satisfactory results. 相似文献
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合成了一种新的钌配合物Ru(PA)2Cl,以叔丁基氢化过氧化物为氧源,考察了它对甲苯,乙苯和环己烷的催化氧化反应。发现它对环己烷和乙苯有良好的催化活性。在适当的反应条件下,催化环己烷氧化成环己醇和环己酮,基于产物的催化转化数达1021。 相似文献
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Dr. Kazuto Suzuki Dr. Joshua Kyle Stanfield Dr. Keita Omura Dr. Yuma Shisaka Dr. Shinya Ariyasu Chie Kasai Dr. Yuichiro Aiba Dr. Hiroshi Sugimoto Prof. Dr. Osami Shoji 《Angewandte Chemie (International ed. in English)》2023,62(13):e202215706
Catching the structure of cytochrome P450 enzymes in flagrante is crucial for the development of P450 biocatalysts, as most structures collected are found trapped in a precatalytic conformation. At the heart of P450 catalysis lies Cpd I, a short-lived, highly reactive intermediate, whose recalcitrant nature has thwarted most attempts at capturing catalytically relevant poses of P450s. We report the crystal structure of P450BM3 mimicking the state in the precise moment preceding epoxidation, which is in perfect agreement with the experimentally observed stereoselectivity. This structure was attained by incorporation of the stable Cpd I mimic oxomolybdenum mesoporphyrin IX into P450BM3 in the presence of styrene. The orientation of styrene to the Mo-oxo species in the crystal structures sheds light onto the dynamics involved in the rotation of styrene to present its vinyl group to Cpd I. This method serves as a powerful tool for predicting and modelling the stereoselectivity of P450 reactions. 相似文献
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采用高效液相色谱法研究了水溶性的对二甲氨甲基杯[ 8 ]芳烃(以下简称杯胺)与二苯胺磺酸钠的相互作用。以水溶性杯胺作流动相添加剂,考察了二苯胺磺酸钠在ODS柱上的色谱保留行为。实验发现,随着杯胺浓度的增大,二苯胺磺酸钠的保留时间逐渐延长,这是由于杯胺与溶质二苯胺磺酸钠形成了包结物的缘故。一方面二苯胺磺酸钠易电离,在ODS柱上保留弱;另一方面,由于杯胺对二苯胺磺酸钠的包结作用,降低了其极性,疏水性增强导致保留时间增加。其包结常数测定为1. 17×104 L/mol,包结比为1∶1,这与荧光法测定值2. 0×104 L/mol一致。同时考察了流动相的添加剂浓度、pH值等因素对二苯胺磺酸钠的保留行为的影响。实验表明,杯胺与二苯胺磺酸钠之间主要存在疏水作用和静电作用。 相似文献