نتایج جستجو برای: rhenium
تعداد نتایج: 1716 فیلتر نتایج به سال:
Abstract: A rhenium complex, [ReBr(CO)3(thf)]2, catalyzed insertion of terminal alkynes into a C–H bond of active methylene sites of 1,3-dicarbonyl compounds. When a catalytic amount of isocyanide or molecular sieves was added to the reaction mixture, the reaction course changed markedly, and insertion of alkynes into a C–C single bond between αand β-positions of cyclic and acyclic β-keto ester...
A mild method for the regioselective coupling of propargyl alcohols and allylsilanes is described. The method employs an air- and moisture-tolerant rhenium-oxo complex ((dppm)ReOCl3) as a catalyst for the formation of sp3-carbon-sp3-carbon bonds without the need for prior activation of the propargyl alcohol as a halide or pseudohalide. The stability of the high oxidation state rhenium complex a...
EXAFS measurements have been carried out on very small osmium and rhenium metal particles supported on MgO. The metal particles were formed via decornposition and subsequent reduction in hydrogen of metal carbonyl clusters.
A loading-unloading-reloading strategy via atomistic simulations is proposed to reveal the strengthening mechanisms of rhenium in nickel-based superalloys at ambient temperature. Simulations reproduce experimentally observed increased flow stress with addition rhenium. Besides usual solid solution strengthening, two novel are uncovered. One that facilitates dislocation nucleation and, thus, inc...
A series of rhenium complexes bearing a pyridine-based PNP-type pincer ligand are synthesized from phosphine as precursors. dinitrogen-bridged dirhenium complex the ligands catalytically converts dinitrogen into ammonia during reaction with KC8 reductant and [HPCy3]BArF4 (Cy=cyclohexyl, ArF=3,5-(CF3)2C6H3) proton source at ?78 °C to afford 8.4 equiv based on atom catalyst. The rhenium-dinitroge...
Rhenium Re –Me alloys where Me = Ni, Fe, or Co were deposited galvanostatically. The plating bath consisted of ammonium perrhenate, nickel or cobalt sulfamate, or iron sulfate, citric acid, and magnesium sulfamate. The effects of bath chemistry and deposition time on faradaic efficiency FE , Re content, and partial deposition currents were determined. Rhenium contents as high as 93 atom % or FE...
Finding a physical approach for increasing the superconducting transition temperature (Tc) is a challenge in the field of material science. Shear strain effects on the superconductivity of rhenium were investigated using magnetic measurements, X-ray diffraction, transmission electron microscopy, and first-principles calculations. A large shear strain reduces the grain size and simultaneously ex...
We report a comprehensive study on the effects of rhenium doping on optical properties and photocarrier dynamics of MoS2 monolayer, few-layer, and bulk samples. Monolayer and few-layer samples of Re-doped (0.6%) and undoped MoS2 were fabricated by mechanical exfoliation, and were studied by Raman spectroscopy, optical absorption, photoluminescence, and time-resolved differential reflection meas...
A new route to luminescent derivatives of androgenic steroids containing a ketone group in the 3- or 17-position has been developed. Reaction with the fac-Re(CO)(3)Cl complex of 3,3'-diamino-2,2'-bipyridine (complex 1) afforded a cyclic aminal product with different steroids. The rate of reaction and yield varies according to the conjugation or steric hindrance around the ketone group.
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