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511.
Synthesis and characterisation of molecularly imprinted catalytic microgels for carbonate hydrolysis
Pamela Pasetto 《Analytica chimica acta》2005,542(1):66-75
Novel molecularly imprinted microgels incorporating arginine and tyrosine side chains as functional monomers have been designed and synthesised with percentages of cross-linker ranging from 70 to 90%. Full chemico-physical characterisation including Mr, coil density and size particle determination concluded that all polymer preparations obtained can be classified as microgels. Molecular imprinting using a phosphate template was used to generate catalytic microgels for the hydrolysis of p-nitrophenyl carbonates. Kinetic characterisation of the catalytic activity of the different preparations indicated that values of critical monomer concentration (CM) and percentage of cross-linker play an important role in determining the catalytic efficiency of the different preparations. Microgels containing 70% cross-linker were the only ones following the Michaelis-Menten saturation model and kinetic parameters were obtained using 4 mg/ml of M397: Vmax = 1.34 × 10−6 M s−1 (S.E. 1.28 × 10−7) and KM = 2.38 × 10−3 M (S.E. 3.1 × 10−4). 相似文献
512.
Abhijit Mitra Pamela J. Seaton Kraig A. Wheeler 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(9):o581-o582
The title new diquinaldine derivative, C27H24N4, forms molecular assemblies organized by intermolecular quinoline π–π stacking [3.356 (3) and 3.440 (3) Å] and both inter‐ and intramolecular N—H⋯N hydrogen bonds [3.039 (3)–3.104 (3) Å and 129 (2)–172 (2)°]. The combination of such interactions provides readily definable contacts that propagate along each crystallographic axis. 相似文献
513.
Riggs-Gelasco PJ Price JC Guyer RB Brehm JH Barr EW Bollinger JM Krebs C 《Journal of the American Chemical Society》2004,126(26):8108-8109
The Fe(II)- and alpha-ketoglutarate-dependent dioxygenases catalyze hydroxylation reactions of considerable biomedical and environmental significance. Recently, the first oxidized iron intermediate in the reaction of a member of this family, taurine:alpha-ketoglutarate dioxygenase (TauD), was detected and shown to be a high-spin Fe(IV) complex. In this study we have used X-ray absorption spectroscopy to demonstrate the presence of a short (1.62 A) interaction between the iron and one of its ligands in the Fe(IV) intermediate but not in the Fe(II) starting complex. The detection of this interaction strongly corroborates the hypothesis that the intermediate contains an Fe=O structural motif. 相似文献
514.
Biau-Hung Chang Pamela C. Coil Mary J. Brown Kenneth W. Barnett 《Journal of organometallic chemistry》1984,270(1):c23-c25
The compound hydrido cyclopentadienyliron dicarbonyl has been shown by infrared and proton NMR to be present in substantial quantities during hydroformylation of propene and 1-pentene in the presence of [(η5-C5H5)Fe(CO)2]2. This and related observations strongly suggest that the hydride is an important link in the catalytic cycle as is HCo(CO)4 in Co2(CO)8-catalyzed olefin hydroformylation. 相似文献
515.
The structure and properties of electrodeposited poly(vinylferrocene) (PVF) films on platinum electrodes (PVF/Pt) were examined by electron microscopy, X-ray photoelectron spectroscopy, various electrochemical techniques and measurements of the film resistance. The data were consistent with a mechanism in which the polymer films are permeable to dis-solved reactants. A theoretical treatment of this situation for chronoamperometry is presented. The oxidation and reduction of a variety of dissolved reactants with redox potentials far removed from that of the PVF/PVF+ system at PVF/Pt occurred by diffusion of the electroactive species through the polymer film and subsequent reaction at the platinum surface. 相似文献
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Zhongyu Wu Zhichao Lin Pamela Mackill Cong Wei John Noonan James Cherniack Deborah Gillis-Landrum 《Journal of Radioanalytical and Nuclear Chemistry》2009,282(3):971-977
Measurement capability and data comparability are essential for emergency response when analytical data from cooperative laboratories
are used for risk assessment and post incident decision making. In this study, the current capability of food emergency response
laboratories for the analysis of 210Po in water was evaluated using a proficiency test scheme in compliance with ISO-43 and ILAC G13 guidelines, which comprises
a test sample preparation and verification protocol and an insightful statistical data evaluation. The results of performance
evaluations on relative bias, value trueness, precision, false positive detection, minimum detection limit, and limit of quantification,
are presented. 相似文献
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