نتایج جستجو برای: alkali metals
تعداد نتایج: 77771 فیلتر نتایج به سال:
A catalytic asymmetric nitro-Mannich (aza-Henry) reaction with rare earth metal/alkali metal heterobimetallic catalysts is described. A Yb/K heterobimetallic catalyst assembled by an amide-based ligand promoted the asymmetric nitro-Mannich reaction to afford enantioenriched anti-b-nitroamines in up to 86% ee. Facile reduction of the nitro functionality allowed for efficient access to optically ...
Density-functional theory and second order Møller-Plesset perturbation theory calculations indicate that halogen atoms bond preferentially to halide substrate atoms on a series of alkali halide surfaces, rather than to the alkali atoms as might be anticipated. An analysis of the electronic structures in each system reveals that this novel adsorption mode is stabilized by the formation of textbo...
Explorations of the A(1+)-RE(3+)-Mo(6+)-O(2-) (A(1+) is an alkali metal cation, RE(3+) is a rare-earth metal cation) quaternary systems prepared by the high-temperature solution growth method led to the title structure, sodium erbium bis-(molyb-date), NaEr(MoO(4))(2). It is isostructural to the scheelite structure (CaWO(4)) and is composed of [MoO(4)](2-) tetra-hedra with symmetry and [(Na/Er)O...
We show that a dilute two-species gas of Fermi-Dirac alkali-metal atoms in a periodic optical lattice may exhibit fractionalization of the particle number when the two components are coupled via a coherent electromagnetic field with a topologically nontrivial phase profile. This results in fractional eigenvalues of the spin operator with vanishing fluctuations. The fractional part can be accura...
Direct irradiation of atropisomeric α-substituted acrylanilides in the presence of alkali metal ions gave high ee values in the 3,4-dihydro-2-quinolin-2-one photoproduct, while in the absence of alkali metal ions, racemic photoproduct was observed. The heavy atom effect leading to enhanced triplet yields alters the reactive pathway leading to the observed enantioselectivity in the photoproduct.
P. Cambon, Centre Octanologique de Bretagne, CNEXO, B. P. 337, 29273 Brest cedex, France J. L. Joron, Institut de Physique du Globe, 4, place Jussieu, 75230 Paris cedex 05, and Laboratoire P. Sue, Centre d'Etudes Nucléaires, B. P. no 2, 91 190 Gif-sur-Yvette, France H. Bougault, Centre Ocdanologique de Bretagne, CNEXO, B. P. 337, 29273 Brest cedex, France M. Treuil, Institut de Physique du Glob...
Vibrational spectra of BH(4)(-) and its isotopic analogues in a crystalline environment of alkali metals cations (K(+), Rb(+), Cs(+)) have been investigated beyond the harmonic approximation using a variational approach supported by computations of B3LYP type anharmonic force fields. From the comparison of the observed and simulated IR spectra, the influence of the anharmonic couplings on the b...
Disclosed is a mild, scalable, and chemoselective catalytic cross-dehydrogenative C-H bond functionalization protocol for the construction of C(sp)-Si bonds in a single step. The scope of the alkyne and hydrosilane partners is substantial, providing an entry point into various organosilane building blocks and additionally enabling the discovery of a number of novel synthetic strategies. Remarka...
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