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41.
42.
Corey T. Love Wojtek Dmowski Karen E. Swider-Lyons 《Journal of solid state chemistry》2011,184(9):2412-2419
We use electrochemistry, high-energy X-ray diffraction (XRD) with pair-distribution function analysis (PDF), and density functional theory (DFT) to study the instabilities of Li2CuO2 at varying state of charge. Rietveld refinement of XRD patterns revealed phase evolution from pure Li2CuO2 body-centered orthorhombic (Immm) space group to multiphase compositions after cycling. The PDF showed CuO4 square chains with varying packing during electrochemical cycling. Peaks in the G(r) at the Cu-O distance for delithiated, LiCuO2, showed CuO4 square chains with reduced ionic radius for Cu in the 3+ state. At full depth of discharge to 1.5 V, CuO was observed in fractions greater than the initial impurity level which strongly affects the reversibility of the lithiation reactions contributing to capacity loss. DFT calculations showed electron removal from Cu and O during delithiation of Li2CuO2. 相似文献
43.
Diimine and diamine ligands that are unable to coordinate to a single metal favour the formation of unusual, high-nuclearity Zn chlorometallate and palladium chloride complexes. 相似文献
44.
A Ni-catalyzed, chemoselective cross-coupling reaction of polyfluoroarenes under mild reaction conditions is reported. A variety of fluorine-containing biaryls are synthesized in good-to-excellent yields. A wide range of substitution patterns and functional groups are tolerated. 相似文献
45.
Cell–cell communication is often achieved via granular exocytosis, as in neurons during synaptic transmission or neuroendocrine
cells during blood hormone control. Owing to its critical role in membrane properties and SNARE function, cholesterol is expected
to play an important role in the highly conserved process of exocytosis. In this work, membrane cholesterol concentration
is systematically varied in primary culture mouse chromaffin cells, and the change in secretion behavior of distinct vesicle
pools as well as pool recovery following stimulation is measured using carbon-fiber microelectrode amperometry. Amperometric
traces obtained from activation of the younger readily releasable and slowly releasable pool (RRP/SRP) vesicles at depleted
cholesterol levels showed fewer sustained fusion pore features (6.1 ± 1.1% of spikes compared with 11.2 ± 1.0% for control),
revealing that cholesterol content influences fusion pore formation and stability during exocytosis. Moreover, subsequent
stimulation of RRP/SRP vesicles showed that cellular cholesterol level influences both the quantal recovery and kinetics of
the later release events. Finally, diverging effects of cholesterol on RRP and the older reserve pool vesicle release suggest
two different mechanisms for the release of these two vesicular pools. 相似文献
46.
Hydrolysis of a Pacman-shaped binuclear magnesium complex of a polypyrrolic Schiff base macrocycle results in the formation of a new magnesium hydroxide cubane that is encapsulated by the macrocyclic framework through both coordinative and hydrogen-bonding interactions. 相似文献
47.
The synthesis of the new cofacial binuclear zinc complex [Zn(2)(L)] of a Schiff-base pyrrole macrocycle is reported. It was discovered that the binuclear microenvironment between the two metals of [Zn(2)(L)] is suited for the encapsulation of anions, leading to the formation of [K(THF)(6)][Zn(2)(μ-Cl)(L)]·2THF and [Bu(n)(4)N][Zn(2)(μ-OH)(L)] which were characterized by X-ray crystallography. Unusually obtuse Zn-X-Zn angles (X = Cl: 150.54(9)° and OH: 157.4(3)°) illustrate the weak character of these interactions and the importance of the cleft preorganization to stabilize the host. In the absence of added anion, aggregation of [Zn(2)(L)] was inferred and investigated by successive dilutions and by the addition of coordinating solvents to [Zn(2)(L)] solutions using NMR spectroscopy as well as isothermal microcalorimetry (ITC). On anion addition, evidence for deaggregation of [Zn(2)(L)], combined with the formation of the 1:1 host-guest complex, was observed by NMR spectroscopy and ITC titrations. Furthermore, [Zn(2)(L)] binds to Cl(-) selectively in THF as deduced from the ITC analyses, while other halides induce only deaggregation. These conclusions were reinforced by density functional theory (DFT) calculations, which indicated that the binding energies of OH(-) and Cl(-) were significantly greater than for the other halides. 相似文献
48.
J.C. Califano A. Uribe J.L. Chang C.L. Becker J.J. Napier V. Kishore D. Zhou G. Love K. Gernhardt J.C. Tolle 《Tetrahedron》2005,61(37):8821-8829
Oligomers of arginine, such as octa-d-arginine amide, are excellent transporters for active drugs through cell membranes and tissue. The synthesis of octa-d-arginine amide, as the nonahydrochloride salt, was approached via a solution phase synthetic route involving the preparation of an octa-d-ornithine intermediate, which was then converted into the desired octa-d-arginine compound through a guanidinylation step. The multi-step synthesis was carried out at pilot scale, resulting in the preparation of 700 g of the target molecule. No chromatographic purification was needed at any step of the process. 相似文献
49.
50.
Data at Einp = 61 and 135 MeV for neutron-hole transitions are used to study the proton-neutron part of the assumed NN force. Collective core-polarization strengths (AL) from the present fits at 135 MeV are consistent with those extracted from the (e, e') reaction for two L = 2 transitions and one L = 4 transition. This is not the case at 61 MeV where the AL values needed to fit the (p, p') data are much smaller for transitions to the hole states. A fully microscopic DWBA fit is successful for the L = 3 transition to the doublet at 2.64 MeV of excitation at Ep = 61 MeV, but fails at 135 MeV; a fully microscopic DWIA calculation provides a reasonable fit to the data at 135 MeV. 相似文献