نتایج جستجو برای: alkali metal

تعداد نتایج: 210259  

Journal: :Journal of the American Chemical Society 2012
Jian Tian Laxmikant V Saraf Birgit Schwenzer Stephanie M Taylor Euan K Brechin Jun Liu Scott J Dalgarno Praveen K Thallapally

Flexible anionic metal-organic frameworks (MOFs) are transformed into neutral heterobimetallic systems via single-crystal-to-single-crystal processes invoked by cation insertion. These transformations are directed by cooperative bond breakage and formation, resulting in expansion or contraction of the 3D framework by up to 33% due to the flexible nature of the organic linker. These MOFs display...

Journal: :Organic & biomolecular chemistry 2012
Jörg M Klein Vittorio Saggiomo Lisa Reck Ulrich Lüning Jeremy K M Sanders

We present the use of hydrazone dynamic combinatorial libraries (DCLs) to identify macrocyclic receptors that are selective for alkaline earth metal ions over alkali metal ions. In particular, the toxic heavy metal ions Sr(2+) and Ba(2+) induce characteristic changes in the DCLs. Four macrocycles were isolated and characterised by LCMS, HRMS, NMR and X-ray crystallography; binding studies by UV...

Journal: :The Journal of General Physiology 1999
Maria Spassova Zhe Lu

To understand the role of permeating ions in determining blocking ion-induced rectification, we examined block of the ROMK1 inward-rectifier K+ channel by intracellular tetraethylammonium in the presence of various alkali metal ions in both the extra- and intracellular solutions. We found that the channel exhibits different degrees of rectification when different alkali metal ions (all at 100 m...

2017
Kate JC Lim Paul Cross Peter Mills Howard M Colquhoun

The effects of varying the alkali metal cation in the high-temperature nucleophilic synthesis of a semi-crystalline, aromatic poly(ether ketone) have been systematically investigated, and striking variations in the sequence distributions and thermal characteristics of the resulting polymers were found. Polycondensation of 4,4-dihydroxybenzophenone with 1,3-bis(4fluorobenzoyl)benzene in diphenyl...

2002
Alena Novoselova Vladimir Khokhlov Vladimir Shishkin

The formal standard redox potentials of samarium (III)/(II) (EZmi+/ Smi+) and europium (III)/(II) (•£,£u3+/eu2+ ) *n molten alkali metal chlorides were measured potentiometrically against a reference chlorine electrode. The Gibbs energy changes and equilibrium constants for the reaction LnCl2(D + V2 Cl2(g) LnCl3(I) were calculated for the salt systems studied. The effect of the cationic composi...

1998
M. Marinescu H. R. Sadeghpour

We address a growing interest in trapping and cooling of mixed-species alkali-metal atoms. Long-range coefficients that arise in the multipole expansion of molecular potentials for unlike alkali-metal dimers are calculated. The coefficients for the heteronuclear alkali-metal dimers corresponding to different molecular symmetries that separate to nS-n8S ,nS-n8P ,nS-n8D , and nP-n8P atomic levels...

2006
J. M. Geremia John K. Stockton Hideo Mabuchi

Optimally extracting information from measurements performed on a physical system requires an accurate model of the measurement interaction. Continuously probing the collective spin of an alkali-metal atom cloud via its interaction with an off-resonant optical probe is an important example of such a measurement where realistic modeling at the quantum level is possible using standard techniques ...

Journal: :Dalton transactions 2014
Raquel Travieso-Puente Mu-Chieh Chang Edwin Otten

Alkali metal salts of redox-active formazanate ligands were prepared, and their structures in the solid-state and in solution are determined. The nitrogen-rich [NNCNN] backbone of formazanates results in a varied coordination chemistry, with both the internal and terminal nitrogen atoms available for bonding with the alkali metal. The potassium salt K[PhNNC(p-tol)NNPh]·2THF (1-K) is dimeric in ...

Journal: :Chemistry 2008
Emanuele Finazzi Cristiana Di Valentin Gianfranco Pacchioni Mario Chiesa Elio Giamello Hongjun Gao Jichun Lian Thomas Risse Hans-Joachim Freund

The adsorption of small amounts of alkali metal atoms (Li, Na, K, Rb, and Cs) on the surface of MgO powders and thin films has been studied by means of EPR spectroscopy and DFT calculations. From a comparison of the measured and computed g values and hyperfine coupling constants (hfccs), a tentative assignment of the preferred adsorption sites is proposed. All atoms bind preferentially to surfa...

2015
Moses Wazingwa Munthali Naoto Matsue

The saturation of negative charges of zeolites by specific cations to modify their physicochemical and catalytic properties has broadened the applications of zeolites. The adsorption behavior of H+ to Li+, Na+, K+, Rb+ and Cs+-saturated Linde-type A, Na-P1, mordenite, X type and Y type zeolites was evaluated at different pH-pM, where pH-pM is equal to log {(M+)/(H+)} and M+ represents either Li...

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