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61.
Hassanin HA El-Shahat MF DeBeer S Smith CA Brasch NE 《Dalton transactions (Cambridge, England : 2003)》2010,39(44):10626-10630
The X-ray structures of three new crystals of nitroxylcobalamin (NOCbl) have been determined. Unlike our earlier reported structure in which NOCbl was partially oxidized (L. Hannibal, C. A. Smith, D. W. Jacobsen and N. E. Brasch, Angew. Chem., Int. Ed. 2007, 46, 5140), the O atom of the nitroxyl ligand is located in a single position with a N=O bond distance of 1.12-1.14 ?, consistent with a double bond. The Co-N-O angle is in the 118.9-120.3 ? range. The α-axial Co-N(dimethylbenzimidazole) (Co-NB3) bond distance is a remarkable 2.32-2.35 ? in length, ~0.1 ? longer than that reported for all other cobalamin structures. The change in the Gibbs free energy for the base-on/base-off equilibrium now correlates extremely well with the Co-NB3 bond distance, as observed for other cobalamins. 相似文献
62.
Under the assumption that the coefficients are regularly varying functions, existence and asymptotic form of strongly decreasing solutions are here studied for a system of two coupled nonlinear second-order equations of Emden–Fowler type, satisfying a subhomogeneity condition. Several examples of application of the main result and a comparison with existing literature complete the paper. 相似文献
63.
64.
Serena Fantasia Björn Bartels Fritz Bliss Fritz Koch Michelangelo Scalone Daniel Spiess Markus Steiner Shaoning Wang Kurt Püntener 《Helvetica chimica acta》2023,106(10):e202300116
The research efforts to attain a suitable process for the timely delivery of Gemlapodect for initial toxicological and phase 1/2 clinical studies are described. The original discovery chemistry route was hampered by considerable safety issues and low overall yield. The safety issues were solved by the introduction of a copper-catalyzed oxidative cyclization while a novel process for the synthesis of the pyrazole building block as well as the implementation of a palladium-catalyzed coupling between the pyrazole amide and the bromo-triazolopyridine scaffolds contributed to improve the route efficiency. Overall, a safe and sustainable process was attained that allowed the production of up to 19.2 kg of drug substance with a reduced number of steps and an increased overall yield. 相似文献
65.
Esposito Serena Setaro Antonio Maddalena Pasqualino Aronne Antonio Pernice Pasquale Laracca Marco 《Journal of Sol-Gel Science and Technology》2011,60(3):388-394
A modified sol–gel method was used to prepare cobalt doped silica thin film with a cobalt content of 10, 20 and 30 mol% (10Co, 20Co and 30Co). The prepared films were annealed at different temperatures in the range 400–1,000 °C, and their structural evolution examined.
The mixed valence cobalt oxide, Co3O4, crystallizes only in the sample with the higher cobalt content, while cobalt silicate is the only crystalline phase detected
in the sample 10Co and 20Co. Both the cobalt content and the temperature of heat treatment resulted to affect the nature of cobalt species dispersed
in the silica matrix. The 30Co was selected for further investigations by FTIR spectroscopy to follow the structural evolution of 30Co film as function of the temperature and UV–Vis to get information on the cobalt valence state. The optical gas-sensing properties
of 30Co films, containing Co3O4 as the major cobalt phase, were studied through the measuring of the film transmittance in dry air and in presence of dry
air containing variable concentrations of polluting gases, CO and NO2. The 30Co samples resulted to be highly sensitive to CO at room temperature. An explanation for the CO sensing characteristics, at
low temperature, was proposed by referring to the physisorption-related mechanics of CO. 相似文献
66.
The accurate determination of E,E-2,4-hexadiendioic acid (t,t-muconic acid), an important urinary biomarker of benzene exposure, is directly performed in human urine by a new two-dimensional liquid chromatographic method. After a first partial separation of urine components by a reversed-phase mechanism and the focalisation of the anionic analytes on a small anion-chromatographic column, a conventional ion-chromatographic analysis with UV detection is carried out. The analytical procedure is fully controlled by the HPLC instrumentation software using an eight-port switch valve. If compared with conventional one-dimensional procedures, the new method produces chromatograms containing a limited number of well resolved peaks and consequently allows better analytical performances: no interfering peaks, absence of bias, repeatability better than 5% in the concentration range 0.09-5 mg dm-3 and a detection limit of 4.0 micrograms dm-3 (alpha = beta = 0.05) for the analysis of real samples. 相似文献
67.
We consider the equation −?2Δu+u=up in a bounded domain Ω⊂R3 with edges. We impose Neumann boundary conditions, assuming 1<p<5, and prove concentration of solutions at suitable points of ∂Ω on the edges. 相似文献
68.
69.
Causo MS Ciccotti G Montemayor D Bonella S Coker DF 《The journal of physical chemistry. B》2005,109(14):6855-6865
We generalize the linearized path integral approach to evaluate quantum time correlation functions for systems best described by a set of nuclear and electronic degrees of freedom, restricting ourselves to the adiabatic approximation. If the operators in the correlation function are nondiagonal in the electronic states, then this adiabatic linearized path integral approximation for the thermal averaged quantum dynamics presents interesting and distinctive features, which we derive and explore in this paper. The capability of these approximations to accurately reproduce the behavior of physical systems is demonstrated by calculating the diffusion constant for an excess electron in a metal-molten salt solution. 相似文献
70.