Electrochemical and 1H NMR studies of proton behavior of ImCl and LiCl solution in acetonitrile

1997 ◽  
Vol 75 (11) ◽  
pp. 1730-1735 ◽  
Author(s):  
Ping He ◽  
Keith E. Johnson
Keyword(s):  
Alkali Metal ◽  
Alkali Metals ◽  
Passive Layer ◽  
Acetonitrile Solution ◽  
Nmr Studies ◽  
Imidazolium Chloride ◽  
Electrochemical Window ◽  
Lithium Chloride Solution ◽  
Stripping Efficiency

The role of the proton in extending the electrochemical window and promoting the stripping efficiency of alkali metals has been studied in acetonitrile solution. The platinum hydride surface generated in the hydrogen evolution was considered responsible for the potential shift of 1-ethyl-3-methyl-1H-imidazolium (Im+) reduction in the absence of lithium. In lithium chloride solution, the lithium layer deposited on the electrode may be the main cause for the stretch of the solvent electrochemical window because of the high overpotential of Im+ reduction on that surface. The proton may affect the properties of the passive layer on newly deposited alkali metal surfaces and then improve the performance of the alkali metal anodes. Keywords: 1-ethyl-3-methyl-1H-imidazolium chloride, protons, acetonitrile, lithium reduction.

scholarly journals Spotlight on Alkali Metals: The Structural Chemistry of Alkali Metal Thallides

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1013
Author(s):  
Stefanie Gärtner
Keyword(s):  
Crystal Structure ◽  
Alkali Metal ◽  
Crystal Structures ◽  
Alkali Metals ◽  
Valence Electron ◽  
Oxidation States ◽  
Valence Electron Concentration ◽  
Base Metals ◽  
Charge Balancing

Alkali metal thallides go back to the investigative works of Eduard Zintl about base metals in negative oxidation states. In 1932, he described the crystal structure of NaTl as the first representative for this class of compounds. Since then, a bunch of versatile crystal structures has been reported for thallium as electronegative element in intermetallic solid state compounds. For combinations of thallium with alkali metals as electropositive counterparts, a broad range of different unique structure types has been observed. Interestingly, various thallium substructures at the same or very similar valence electron concentration (VEC) are obtained. This in return emphasizes that the role of the alkali metals on structure formation goes far beyond ancillary filling atoms, which are present only due to charge balancing reasons. In this review, the alkali metals are in focus and the local surroundings of the latter are discussed in terms of their crystallographic sites in the corresponding crystal structures.

Spectrophotometric study of ion pairing in diphenylmethyl alkali metals salts

1979 ◽  
Vol 57 (9) ◽  
pp. 999-1005 ◽  
Author(s):  
E. Buncel ◽  
B. C. Menon ◽  
J. P. Colpa
Keyword(s):  
Alkali Metal ◽  
Alkali Metals ◽  
Ion Pairs ◽  
Ion Pairing ◽  
Spectrophotometric Study ◽  
Metal Salts ◽  
Effect Of Temperature ◽  
Alkali Metal Salts ◽  
Nmr Studies ◽  
Temperature Changes

A spectrophotometric study of diphenylmethyllithium (DPM−Li+) and diphenylmethyl-potassium (DPM−K+) in ethereal solvents has yielded information on ion pairing and solvation phenomena in these carbanion systems. Different spectral absorptions are observed, characteristic of two types of contact ion pairs (unsolvated and partially solvated) as well as the solvent separated ion pair species, on varying the cation and solvent. This contrasts with our previous observations with triphenylmethyl alkali metal salts where only contact and solvent separated ion pairs were observed. The effect of 18-crown-6 polyether and the effect of temperature changes on the ion pairing equilibria are evaluated. Thermodynamic parameters are obtained for equilibria pertaining to the DPM−Li+/THF and DPM−Li+/DME systems. The results are discussed in relation to literature reports on ion pairing in these systems as derived from nmr studies. Comparison with triphenylmethyl alkali metal salts yields information relating to delocalization and steric effects on ion pairing.

Room Temperature Alkali Metal Reduction of Carbon Dioxide

2020 ◽  
Author(s):  
Lucas A. Freeman ◽  
Akachukwu D. Obi ◽  
Haleigh R. Machost ◽  
Andrew Molino ◽  
Asa W. Nichols ◽  
...  
Keyword(s):  
Alkali Metal ◽  
Alkali Metals ◽  
Room Temperature ◽  
Chemical Reduction ◽  
Bond Cleavage ◽  
Open Shell ◽  
Metal Reduction ◽  
One Pot ◽  
Earth Abundant ◽  
Electron Reduction

The reduction of the relatively inert carbon–oxygen bonds of CO<sub>2</sub> to access useful CO<sub>2</sub>-derived organic products is one of the most important fundamental challenges in synthetic chemistry. Facilitating this bond-cleavage using earth-abundant, non-toxic main group elements (MGEs) is especially arduous because of the difficulty in achieving strong inner-sphere interactions between CO<sub>2</sub> and the MGE. Herein we report the first successful chemical reduction of CO<sub>2</sub> at room temperature by alkali metals, promoted by a cyclic(alkyl)(amino) carbene (CAAC). One-electron reduction of CAAC-CO<sub>2</sub> adduct (<b>1</b>) with lithium, sodium or potassium metal yields stable monoanionic radicals clusters [M(CAAC–CO<sub>2</sub>)]<sub>n</sub>(M = Li, Na, K, <b> 2</b>-<b>4</b>) and two-electron alkali metal reduction affords open-shell, dianionic clusters of the general formula [M<sub>2</sub>(CAAC–CO<sub>2</sub>)]<sub>n </sub>(<b>5</b>-<b>8</b>). It is notable that these crystalline clusters of reduced CO<sub>2</sub> may also be isolated via the “one-pot” reaction of free CO<sub>2</sub> with free CAAC followed by the addition of alkali metals – a reductive process which does not occur in the absence of carbene. Each of the products <b>2</b>-<b>8</b> were investigated using a combination of experimental and theoretical methods.<br>

Cation-Induced Dimerization of Crown-Substituted Gallium Phthalocyanine by Complexing with Alkali Metals: The Crucial Role of a Central Metal

2021 ◽  
Vol 60 (3) ◽  
pp. 1948-1956
Author(s):  
Lyudmila A. Lapkina ◽  
Anna A. Sinelshchikova ◽  
Kirill P. Birin ◽  
Vladimir E. Larchenko ◽  
Mikhail S. Grigoriev ◽  
...  
Keyword(s):  
Crucial Role ◽  
Alkali Metals ◽  
Central Metal

scholarly journals Catalytic Systems Based on Cp2ZrX2 (X = Cl, H), Organoaluminum Compounds and Perfluorophenylboranes: Role of Zr,Zr- and Zr,Al-Hydride Intermediates in Alkene Dimerization and Oligomerization

Catalysts ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 39
Author(s):  
Lyudmila V. Parfenova ◽  
Pavel V. Kovyazin ◽  
Almira Kh. Bikmeeva ◽  
Eldar R. Palatov
Keyword(s):  
Diffusion Coefficients ◽  
Organoaluminum Compounds ◽  
Zirconium Hydride ◽  
Nmr Studies ◽  
Catalytic Systems ◽  
Selective Formation

The activity and chemoselectivity of the Cp2ZrCl2-XAlBui2 (X = H, Bui) and [Cp2ZrH2]2-ClAlEt2 catalytic systems activated by (Ph3C)[B(C6F5)4] or B(C6F5)3 were studied in reactions with 1-hexene. The activation of the systems by B(C6F5)3 resulted in the selective formation of head-to-tail alkene dimers in up to 93% yields. NMR studies of the reactions of Zr complexes with organoaluminum compounds (OACs) and boron activators showed the formation of Zr,Zr- and Zr,Al-hydride intermediates, for which diffusion coefficients, hydrodynamic radii, and volumes were estimated using the diffusion ordered spectroscopy DOSY. Bis-zirconium hydride clusters of type x[Cp2ZrH2∙Cp2ZrHCl∙ClAlR2]∙yRnAl(C6F5)3−n were found to be the key intermediates of alkene dimerization, whereas cationic Zr,Al-hydrides led to the formation of oligomers.

Thermally Induced Electron Transfer in a CsCoFe Prussian Blue Derivative: The Specific Role of the Alkali-Metal Ion

2004 ◽  
Vol 116 (28) ◽  
pp. 3814-3817 ◽  
Author(s):  
Anne Bleuzen ◽  
Virginie Escax ◽  
Alban Ferrier ◽  
Françoise Villain ◽  
Michel Verdaguer ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Alkali Metal ◽  
Prussian Blue ◽  
Metal Ion ◽  
Specific Role ◽  
Alkali Metal Ion ◽  
Thermally Induced

AXITURB: A Full Computer Implementation of the NASA Design Procedure for Axial-Flow Turbines

1993 ◽  
Author(s):  
P. C. Lu ◽  
Chen-Ying Wang
Keyword(s):  
Alkali Metals ◽  
Axial Flow ◽  
Design Procedure ◽  
Rankine Cycle ◽  
Eutectic Alloys ◽  
Singular Case ◽  
Cycle Space ◽  
Power Turbine ◽  
Parametric Studies

Abstract A recent task to design a Rankine-cycle space-power turbine system employing eutectic alloys of alkali metals prompted the present authors to re-examine the NASA design procedure for axial-flow turbines, as outlined by Glassman and Futral (and based on works of Stewart) in 1963. After clarifying the role of the singular case of a single-stage turbine, and organizing the procedure in clear steps, a computer program AXITURB was written. The present paper reports essentially the success of AXITURB in performing parametric studies of NaK and CsK turbines (using 78.4% and 23.1%, respectively, of potassium by weight), after re-generating all the reported NASA designs for turbines employing pure Na, K and Cs. An outline of design steps is also given. AXITURB has been put in public domain. Its heavily commented source code in FORTRAN is available to designers for adaption or modification.

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