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81.
The conversion of adamantane exclusively to 1-adamantyl trifluoroacetate in a refluxing trifluoroacetic acid solution of palladium acetate at 1 atm of air or nitrogen was confirmed. The conversion can be made quantitative. The 1-adamantyl trifluoroacetate was hydrolysed to yield 1-adamantanol in 90% isolated yield. The adamantane functionalization is accompanied by concomitant formation of a palladium mirror. 相似文献
82.
Electrochemical and spectroelectrochemical properties of five cobalt(III) acetate complexes [CoIII3(mu3-O)(CH3CO2)5(OR)(py)3][PF6] are described, where py=pyridine and R=OCCH3 (A), H (B), CH3 (C), CH2CH=CH2 (D), and CH2C6H5 (E). Each is reduced irreversibly as observed by cyclic voltammetry at room temperature and at -40 degrees C in acetonitrile at scan rates up to 20 V s(-1), but oxidized reversibly to a mixed-valence Co(III)2Co(IV) species at approximately 1.23 V vs the ferrocenium/ferrocene couple. Controlled potential coulometry confirmed a one-electron-oxidation process. Spectroelectrochemical oxidation of A at 5 degrees C showed isosbestic points in the electronic absorption spectrum that showed the oxidized complex to be stable in solution for at least 1 h. 相似文献
83.
14‐Vertex Heteroboranes with 14 Skeletal Electron Pairs: An Experimental and Computational Study 下载免费PDF全文
Dr. Alasdair P. M. Robertson Nicholas A. Beattie Dr. Greig Scott Dr. Wing Y. Man John J. Jones Prof. Stuart A. Macgregor Dr. Georgina M. Rosair Prof. Alan J. Welch 《Angewandte Chemie (International ed. in English)》2016,55(30):8706-8710
Three isomers of [(Cp*Ru)2C2B10H12], the first examples of 14‐vertex heteroboranes containing 14‐skeletal electron pairs, have been synthesized by the direct electrophilic insertion of a {Cp*Ru+} fragment into the anion [4‐Cp*‐4,1,6‐RuC2B10H12]?. All three compounds have the same unique polyhedral structure having an approximate Cs symmetry and featuring a four‐atom trapezoidal face. X‐ray diffraction studies could confidently identify only one of the two cage C atoms in each structure. The other C atom position has been established by a combination of i) best fitting of computed and experimental 11B and 1H NMR chemical shifts, and ii) consideration of the lowest computed energy for series of isomers studied by DFT calculations. In all three isomers, one cage C atom occupies a degree‐4 vertex on the short parallel edge of the trapezium. 相似文献
84.
Beattie SD Humphries T Weaver L McGrady GS 《Chemical communications (Cambridge, England)》2008,(37):4448-4450
An in situ thermal desorption study of solvated aluminum hydride (alane) by transmission electron microscopy and selected area diffraction has permitted characterisation of the structural and morphological changes during desorption of solvent and hydrogen in real-time; this powerful technique for studying hydrogen storage materials complements several others already employed. 相似文献
85.
The time dependence of the dynamic mobility and the ultrasonic attenuation of octane and decane oil-in-water emulsions stabilized by sodium dodecyl sulfate (SDS) was measured. The emulsions grew to larger droplets due to Ostwald ripening. The growth rate measured by attenuation depends on the surfactant concentration and the polydispersity of the emulsion. At surfactant concentrations below the critical micelle concentration (cmc) of SDS, the growth was linear with time and the rate was dependent on the polydispersity of the drops; the rate was several times faster than that predicted on the basis of a diffusion growth mechanism. Above the cmc, however, as the droplets grew in size there was a point at which the rate of growth increased, which corresponds to the droplet size at which depletion forces due to the surfactant micelles become significant. Under these conditions both the electroacoustic dynamic mobility and the acoustic attenuation spectra displayed characteristics of flocs: a large decrease in the phase lag at higher frequencies in the dynamic mobility spectrum and a decrease in the attenuation coefficient at low-megahertz frequencies with an increase at higher frequencies. This depletion flocculation enhancement in ripening rates in the presence of SDS micelles provides another, alternative, and self-consistent mechanism for the effect of surfactant micelles on Ostwald ripening. 相似文献
86.
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88.
Synthesis of 2-C-fluoromethyl-myo-inositol from DL-l-O-benzyl-2-oxiranyl-3, 4, 5, 6-tetra-O-benzyl-myo-inositol is described. 相似文献
89.
Urgast DS Ellingsen DG Berlinger B Eilertsen E Friisk G Skaug V Thomassen Y Beattie JH Kwun IS Feldmann J 《Analytical and bioanalytical chemistry》2012,404(1):89-99
In recent years, bismuth has been promoted as a "green element" and is used as a substitute for the toxic lead in ammunition and other applications. However, the bioavailability and toxicity of bismuth is still not very well described. Following a hunting accident with bismuth-containing shots, a bioavailability study of bismuth from metal pellets inoculated into rat limb muscles was carried out. Bismuth could be found in urine and blood of the animals. Bio-imaging using laser ablation ICP-MS of thin sections of the tissue around the metal implant was carried out to find out more about the distribution of the metal diffusing into the tissue. Two laser ablation systems with different ablation cell designs were compared regarding their analytical performance. Low concentrations of bismuth showing a non-symmetrical pattern were detected in the tissue surrounding the metal implant. This was partly an artefact from cutting the thin sections but also bio-mobilisation of the metals of the implant could be seen. An accumulation of zinc around the implant was interpreted as a marker of inflammation. Challenges regarding sample preparation for laser ablation and bio-imaging of samples of diverse composition became apparent during the analysis. 相似文献
90.
Urgast DS Ou O Gordon MJ Raab A Nixon GF Kwun IS Beattie JH Feldmann J 《Analytical and bioanalytical chemistry》2012,402(1):287-297
The kinetics of zinc absorption, metabolism and excretion is extensively studied by nutritionists. Stable isotopes of zinc
can be used to identify body zinc compartments that have different turnover kinetics. Since the compartments might belong
to physiological subsections of different organs, there is a need for microsampling analysis to determine isotope ratios of
the trace element zinc in tissue samples. Here, we study the feasibility to use laser ablation coupled to quadrupole ICP-MS
for the determination of zinc tracers given to rats at different time points with the aim to generate isotope ratio bioimages
of heart tissue. A double tracer (70Zn and 67Zn) experiment with rats was designed to label the exchangeable zinc pool as well as the stable zinc pool. The isotope ratios
determined by laser ablation ICP-MS were evaluated by additional measurements of tissue digests. Accumulated tracers which
made up more than 0.1% of total zinc could be identified in the tissues of the treated rats. It was established that at least
50 measurements from the microsampling were necessary to distinguish between controls and a tracer treated rat resulting in
reduced resolution of the bioimage. With the parameters used, features in the tissue thin sections of at least 250 μm2 in size are necessary to detect the incorporation of a tracer. When different time points have to be measured, higher precisions
are required and therefore a larger area needs to be ablated (1 mm2). Using the bioimages and pool measurements from one physiological feature, it was possible to show that the aorta cell walls
incorporate the zinc tracer at the different time points. 相似文献