Results 181 to 190 of about 9,235 (228)

The silyl-cupration and stannyl-cupration of allenes

Tetrahedron, 1989
Abstract The stoichiometric silyl-cupration of allene 7, followed directly by treating the intermediate cuprate with a proton, with a range of carbon electrophiles, and with chlorine gives the vinylsilanes 8–13. Alternatively, when iodine is the electrophile, the product is the vinyl iodide 16. This can then be metallated and treated with a proton or
Ian Fleming, Michael Rowley, Purificacíon Cuadrado, Ana M. González-Nogal, Francisco J. Pulido   +4 more
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Superexchange anisotropy in the cuprates

Physical Review B, 1994
The single-bond superexchange anisotropy resulting from the 2${\mathit{p}}_{\mathrm{\ensuremath{\sigma}}}$ and the 2${\mathit{p}}_{\mathit{z}}$ orbitals on the ligand ion of the cuprates is analyzed for a general case in which the oxygen octahedra surrounding each copper rotate around a general axis in the ${\mathrm{CuO}}_{2}$ plane.
, Entin-Wohlman, , Aharony, , Shekhtman
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Direct Cupration of Fluoroform

Journal of the American Chemical Society, 2011
We have found the first reaction of direct cupration of fluoroform, the most attractive CF(3) source for the introduction of the trifluoromethyl group into organic molecules. Treatment of CuX (X = Cl, Br, I) with 2 equiv of MOR (M = K, Na) in DMF or NMP produces novel alkoxycuprates that readily react with CF(3)H at room temperature and atmospheric ...
Alessandro, Zanardi, Maxim A, Novikov, Eddy, Martin, Jordi, Benet-Buchholz, Vladimir V, Grushin   +4 more
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On the Reaction Mechanism of “Higher-Order Cuprate”, Alias “Lipshutz Cuprate”

Bulletin of the Chemical Society of Japan, 2004
Abstract An organocuprate reagent of the R2Cu(CN)Li composition introduced by Lipshutz has been frequently used in organic synthesis because its reactivity in some reactions is higher than that of the standard Gilman reagent R2CuLi. The higher reactivity of the Lipshutz cuprate was once ascribed to a dianionic tri-coordinated copper(I) (“
Eiichi Nakamura, Naohiko Yoshikai
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Electronic localization in the cuprates

Physical Review B, 1996
A simplified three-band model for the cuprates is proposed which reproduces three qualitatively interesting features of the electronic structure of these materials. These are the intense satellite peak observed in the photoemission spectrum, the antiferromagnetic coupling of Cu 3{ital d} spins, and the tendency toward localization of doped holes, as ...
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Ordering Phenomena in Cuprates

2005
Results of light-scattering experiments in Bi2Sr2CaCu2O8+δ (Bi-2212), La2–xSrxCuO4 (LSCO), and YBa2Cu3O6+x (Y-123) single crystals are presented. The emphasis is placed on the low doping range where the evolution of the metallic state from the antiferromagnetic one is studied.
Hackl, Rudi, Tassini, Leonardo, Venturini, Francesca, Hartinger, Christine, Erb, Andreas, Kikugawa, Naoki, Fujita, Toshitsu   +6 more
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Thermopower of the superconducting cuprates

Physical Review B, 1995
The normal-state thermoelectric power of the high-{ital T}{sub {ital c}} superconducting cuprates shows a systematic but unusual dependence on temperature and on the concentration of holes in the CuO{sub 2} planes. In this paper it is shown that the observed pattern is predicted within a conventional Fermi-liquid picture and follows from the ...
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Rehybridization and pairing in the cuprates

Physical Review B, 1996
The correlation effects associated with the formation of the local Zhang-Rice singlet are shown to lead to a bound pair of holes in a simple three-band cluster model of the cuprates. The symmetry of the pair function is {ital d}{sub {ital x}{sup 2}{minus}{ital y}{sup 2}}.
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Plasmons in cuprate superconductors

Physical Review B, 1990
The customary way of determining the complex dielectric constant from the measured reflectance spectra suffers from large uncertainties because of the extrapolations required for the Kramers-Kronig transformation. To avoid these, a method is introduced in which reflectance and ellipsometric data on single crystals and epitaxial films are combined ...
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Optical properties of cuprates

Physica C: Superconductivity, 1994
We present inhomogeneous Hartree-Fock plus RPA calculations showing the evolution of optical absorption bands with doping. The observed midinfrared (MIR) band and other features are explained and related to the transfer of spectral weight observed in other spectroscopies.
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