نتایج جستجو برای: alkali metals

تعداد نتایج: 77771  

Journal: :Molecules 2010
Tatsuya Nitabaru Naoya Kumagai Masakatsu Shibasaki

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 ...

Journal: :Physical review letters 2006
Bo Li Angelos Michaelides Matthias Scheffler

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...

2010
Dan Zhao Feifei Li Wendan Cheng Hao Zhang

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...

Journal: :Physical review letters 2002
Janne Ruostekoski Gerald V Dunne Juha Javanainen

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...

Journal: :Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology 2014
Anoklase Jean-Luc Ayitou Anthony Clay Elango Kumarasamy Steffen Jockusch J Sivaguru

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.

2008
P. Cambon

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...

Journal: :The journal of physical chemistry. A 2006
Philippe Carbonnière Hans Hagemann

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...

Journal: :Journal of the American Chemical Society 2017
Anton A Toutov Kerry N Betz David P Schuman Wen-Bo Liu Alexey Fedorov Brian M Stoltz Robert H Grubbs

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...

2017
Li Qingfeng Flemming Borup Irina Petrushina Niels J. Bjerrum

Journal: :THE REVIEW OF HIGH PRESSURE SCIENCE AND TECHNOLOGY 1994

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