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A synthetic route with two consecutive coordination chemistry steps on a solid support affords tris-heteroleptic ruthenium(II) polypyridyl complexes with high purity and in good yields. As an application we report the identification of a nanomolar acetylcholinesterase inhibitor from a small ruthenium complex library synthesized on Lanterns. 相似文献
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Bulk superconducting samples of type Tl0.5Pb0.5Sr1.6Ba0.4CaCu2−x
Ru
x
O7−δ, (Tl, Pb)/Sr-1212, with 0.0 ≤ x ≤ 0.525 were prepared by the conventional one-step solid-state reaction technique. The prepared samples were investigated
using X-ray powder diffraction, electrical resistivity and electron paramagnetic resonance (EPR) measurements. Enhancement
of the phase formation, superconducting transition temperature T
c and hole carriers concentration P was observed up to x = 0.075. For x > 0.075, a reverse trend was observed. EPR spectra were measured at different temperatures (120–290 K) for all prepared samples.
The number of spins N participating in the resonance and the paramagnetic susceptibility χ were calculated as a function of both Ru-content and
temperature. N and χ increased as the Ru-content increased. A linear relationship between logN and 1/T was established, from which the activation energy E
a was calculated as a function of the Ru-content. The temperature dependence of χ was fitted according to Curie–Weiss type
of magnetic behavior. Curie constant C, Curie temperature θ, the effective magnetic moment μ and the electronic specific heat γ were estimated as a function of the Ru-content. 相似文献
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Jiang Yuan Jinming Duan Wei Li Christopher P. Saint Dennis Mulcahy 《Chromatographia》2017,80(2):247-257
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Zheng X Mulcahy ME Horinek D Galeotti F Magnera TF Michl J 《Journal of the American Chemical Society》2004,126(14):4540-4542
We describe the preparation of a compound whose molecules consist of two metal sandwich stands carrying tentacles with affinity to metal surfaces and holding an axle that carries a dipolar or a nonpolar rotator. The dipolar rotor exists as three pairs of enantiomers, rapidly interconverting at room temperature. When mounted on a gold surface, each molecule represents a chiral altitudinal rotor, with the rotator axle parallel to the surface. The surface-mounted rotor molecules are characterized by several spectroscopic and imaging techniques. At any one time, in about one-third of the dipolar rotors the rotator is free to turn and the direction of its dipole can be flipped by the electric field applied by an STM tip, as revealed by differential barrier height imaging. Molecular dynamics calculations suggest that electric field normal to the surface causes members of one pair of enantiomers to rotate unidirectionally. 相似文献
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ABSTRACTBayfol (PC-PBT blend ?lm) is a class of polymeric solid-state nuclear track detector which has a lot of applications in several radiation detection ?elds. It is a bisphenol-A polycarbonate PC blended with polybutylene terephthalate PBT. Bayfol/Palladium (PC-PBT/Pd) nanocomposite films have been deposited using the molding technique. It is worth mentioning that this report is almost the first one dealing with the topic of the changes of physical properties of Bayfol/Pd nanocomposite due to laser exposure. Samples from PC-PBT/Pd (5?wt%) nanocomposite were exposed to IR-pulsed laser of 5-W power, capable of producing 2000 pulses per second with pulse duration of 200?ns at 904?nm. The laser fluences were in the range 2–25?J/cm2. The resultant modi?cations in the exposed nanocomposite samples have been studied as a function of fluence using different characterization techniques such as X-ray diffraction (XRD), UV spectroscopy and color difference studies. The results indicate the proper dispersion of Pd nanoparticles in the PC-PBT matrix that causes a strong intermolecular interaction between Pd and PC-PBT, resulted in an increase in refractive index and the amorphous phase. Also, it is found that the laser exposure reduces the optical energy gap that could be attributed to the increase in structural disorder of the exposed PC-PBT/Pd nanocomposites due to crosslinking. Further, the color intensity ΔE, which is the color difference between the exposed samples and the non-exposed one, was increased with increasing the laser fluence, convoyed by a significant increase in the green and yellow color components. 相似文献
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The synthesis of β-carbolines is a mature field, yet new methods are desirable to introduce new functionality onto the core scaffold. We describe the incorporation of an additional fused ring onto the β-carboline via a novel palladium-catalyzed, one-pot Sonogashira coupling/intramolecular [2+2+2] cyclization. This method generates three rings in one flask and produces an annulated β-carboline in 80% yield. A preliminary mechanistic study into the sequence of events is described, which confirms an unprecedented catalytic role for palladium. 相似文献
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羧甲基纤维素钠水凝胶的制备及其生物降解性研究 总被引:9,自引:0,他引:9
用羧甲基纤维素钠(CMC—Na)制得了含水量高达98%的水凝胶,考察了防腐剂、交联剂、无机态氮素、有机态氮素、碳水化合物的加入量以及环境中pH值等因素对生物降解性的影响。结果表明:制备条件不同,水凝胶的生物降解性不同;环境中一定量铵根离子的存在有利于水凝胶的生物降解;在pH=5.2的环境中纤维素酶活性最高,降解程度最大。 相似文献
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Reduction of functional groups with hydrogen gas is one of the most important reactions in organic chemistry, dating to the first hydrogenation of ethene to ethane reported by Von Wilde in 18741. Indeed, alkenes are generally rapidly hydrogenated, in the presence of a catalyst, usually, platinum, Raney nickel, palladium, or rhodium on carbon, to the corresponding alkane via heterogeneous reaction. Most undergraduate, introductory texts introduce this reaction as occurring via a stermspecific syn addition, although this is an oversimplification, due to possible rearrangements on the catalyst surface2. While the chemistry of Vitamin C (L-ascorbic acid), in regards to oxidative degradation, is well studied, its behavior under reductive conditions has been relatively overlooked. The catalytic reduction of ascorbic acid has been reported earlier (24 hours, palladium catalyst, water, 50°) by workers at Pfizer3. 相似文献