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151.
152.
Anna Maria Deobald Greice Tabarelli Oscar E.D. Rodrigues Antônio L. Braga 《Tetrahedron letters》2010,51(26):3364-3367
We present here our results of the efficient synthesis of azido arylselenides and azido aryldiselenides under mild conditions. Starting from nitrogen-substituted benzenes, we incorporated selenium atom at aromatic ring and obtained amino arylselenides and diselenides in satisfactory yields. Treatment of these compounds with iso-pentyl nitrite (i-C5H11ONO) and azido trimethylsilane (Me3SiN3) in THF affords a variety of azido arylselenides and diselenides in good to excellent yields. 相似文献
153.
154.
Oscar Loaiza-Brito 《Nuclear Physics B》2004,680(1-3):271-301
We study the equivalence among orientifold three-planes in the context of the Atiyah–Hirzebruch spectral sequence. This equivalence refers to the fact that two different cohomology classes in the same cohomology group, which classify the orientifolds, are lifted to the same trivial class in K-theory. The physical interpretation of this mathematical algorithm is given by the role of D-brane instantons. By following some recent ideas, we extend the sequence to include a classification of NS–NS fluxes. We find that such equivalences, in the low energy limit of the dynamics on the worldvolume of type IIB D3-branes on top of the orientifolds, are interpreted as the
duality in four-dimensional
SYM theories. 相似文献
155.
Reverdito Ana María García Mariano Hernán Salerno Alejandra Locani Oscar Alberto Perillo Isabel Amalia 《平面色谱法杂志一现代薄层色谱法》2007,20(3):227-230
JPC – Journal of Planar Chromatography – Modern TLC - When the components of a reaction mixture cannot be quantified by UV-visible spectrophotometry, because the λmax values of... 相似文献
156.
Sugimoto Y Jelinek P Pou P Abe M Morita S Perez R Custance O 《Physical review letters》2007,98(10):106104
Vacancy-mediated lateral manipulations of intrinsic adatoms of the Si(111)-(7x7) surface at room temperature are reported. The topographic signal during the manipulation combined with force spectroscopy measurements reveals that these manipulations can be ascribed to the so-called pulling mode, and that the Si adatoms were manipulated in the attractive tip-surface interaction regime at the relatively low short-range force value associated to the manipulation set point. First-principles calculations reveal that the presence of the tip induces structural relaxations that weaken the adatom surface bonds and manifests in a considerable local reduction of the natural diffusion barriers to adjacent adsorption positions. Close to the short-range forces measured in the experiments, these barriers are lowered near the limit that enables a thermally activated hopping at room temperature. 相似文献
157.
Dr. Oscar Tutusaus Dr. Rana Mohtadi Dr. Timothy S. Arthur Dr. Fuminori Mizuno Dr. Emily G. Nelson Prof. Yulia V. Sevryugina 《Angewandte Chemie (International ed. in English)》2015,54(27):7900-7904
Unlocking the full potential of rechargeable magnesium batteries has been partially hindered by the reliance on chloride‐based complex systems. Despite the high anodic stability of these electrolytes, they are corrosive toward metallic battery components, which reduce their practical electrochemical window. Following on our new design concept involving boron cluster anions, monocarborane CB11H12? produced the first halogen‐free, simple‐type Mg salt that is compatible with Mg metal and displays an oxidative stability surpassing that of ether solvents. Owing to its inertness and non‐corrosive nature, the Mg(CB11H12)2/tetraglyme (MMC/G4) electrolyte system permits standardized methods of high‐voltage cathode testing that uses a typical coin cell. This achievement is a turning point in the research and development of Mg electrolytes that has deep implications on realizing practical rechargeable Mg batteries. 相似文献
158.
Postsynthetic Improvement of the Physical Properties in a Metal–Organic Framework through a Single Crystal to Single Crystal Transmetallation 下载免费PDF全文
Thais Grancha Dr. Jesús Ferrando‐Soria Prof. Dr. Hong‐Cai Zhou Prof. Dr. Jorge Gascon Dr. Beatriz Seoane Dr. Jorge Pasán Dr. Oscar Fabelo Prof. Dr. Miguel Julve Dr. Emilio Pardo 《Angewandte Chemie (International ed. in English)》2015,54(22):6521-6525
A single crystal to single crystal transmetallation process takes place in the three‐dimensional (3D) metal–organic framework (MOF) of formula MgII2{MgII4[CuII2(Me3mpba)2]3}?45 H2O ( 1 ; Me3mpba4?=N,N′‐2,4,6‐trimethyl‐1,3‐phenylenebis(oxamate)). After complete replacement of the MgII ions within the coordination network and those hosted in the channels by either CoII or NiII ions, 1 is transmetallated to yield two novel MOFs of formulae Co2II{CoII4[CuII2(Me3mpba)2]3}?56 H2O ( 2 ) and Ni2II{NiII4[CuII2(Me3mpba)2]3}? 54 H2O ( 3 ). This unique postsynthetic metal substitution affords materials with higher structural stability leading to enhanced gas sorption and magnetic properties. 相似文献
159.
Synthesis of an [(NHC)2Pd(SiMe3)2] Complex and Catalytic cis‐Bis(silyl)ations of Alkynes with Unactivated Disilanes 下载免费PDF全文
Melvyn B. Ansell Dr. Debbie E. Roberts Prof. F. Geoffrey N. Cloke Dr. Oscar Navarro Dr. John Spencer 《Angewandte Chemie (International ed. in English)》2015,54(19):5578-5582
The novel complex cis‐[(ITMe)2Pd(SiMe3)2 (ITMe=1,3,4,5‐tetramethylimidazol‐2‐ylidene) has been synthesized by mild oxidative cleavage of Me3SiSiMe3 using [(ITMe)2Pd0]. The use of this complex as precatalyst for the cis‐bis(silyl)ation of alkynes using unactivated disilanes is reported. 相似文献
160.
The Synthesis of B2(SIDip)2 and its Reactivity Between the Diboracumulenic and Diborynic Extremes 下载免费PDF全文
Julian Bhnke Holger Braunschweig Theresa Dellermann William C. Ewing Kai Hammond J. Oscar C. Jimenez‐Halla Thomas Kramer Jan Mies 《Angewandte Chemie (International ed. in English)》2015,54(46):13801-13805
A new compound with the formula L‐B2‐L wherein the stabilizing ligand (L) is 1,3‐bis[diisopropylphenyl]‐4,5‐dihydroimidazol‐2‐ylidene (SIDip) has been synthesized, isolated, and characterized. The π‐acidity of the SIDip ligand, intermediate between the relatively non‐acidic IDip (1,3‐bis[diisopropylphenyl]imidazol‐2‐ylidene) ligand and the much more highly acidic CAAC (1‐[2,6‐diisopropylphenyl]‐3,3,5,5‐tetramethylpyrrolidin‐2‐ylidene) ligand, gives rise to a compound with spectroscopic, electrochemical, and structural properties between those of L‐B2‐L compounds stabilized by CAAC and IDip. Reactions of all three L‐B2‐L compounds with CO demonstrate the differences caused by their respective ligands, as the π‐acidities of the CAAC and SIDip carbenes enabled the isolation of bis(boraketene) compounds (L(OC)B‐B(CO)L), which could not be isolated from reactions with B2(IDip)2. However, only B2(IDip)2 and B2(SIDip)2 could be converted into bicyclic bis(boralactone) compounds. 相似文献