Spectroscopy of alkali metals in fused alkali metal salts

1968 ◽  
Vol 72 (4) ◽  
pp. 1111-1116 ◽  
Author(s):  
James F. Rounsaville ◽  
Joseph J. Lagowski
Keyword(s):  
Alkali Metal ◽  
Alkali Metals ◽  
Metal Salts ◽  
Alkali Metal Salts

scholarly journals Theoretical and Experimental Studies on Alkali Metal Phenoxyacetates

2012 ◽  
Vol 27 ◽  
pp. 321-328
Author(s):  
E. Regulska ◽  
M. Samsonowicz ◽  
R. Świsłocka ◽  
W. Lewandowski
Keyword(s):  
Alkali Metal ◽  
Alkali Metals ◽  
Chemical Shifts ◽  
Dipole Moments ◽  
Population Analysis ◽  
Experimental Studies ◽  
Metal Salts ◽  
Phenoxyacetic Acid ◽  
Alkali Metal Salts ◽  
Geometrical Structures

Optimized geometrical structures of alkali metal phenoxyacetates were obtained using B3LYP/6-311++G** method. Geometric and magnetic aromaticity indices, dipole moments, and energies were calculated. Atomic charges on the atoms of phenoxyacetic acid molecule and its alkali metal salts were calculated by Mulliken, APT (atomic polar tensor), NPA (natural population analysis), MK (Merz-Singh-Kollman method), and ChelpG (charges from electrostatic potentials using grid-based method) methods. The theoretical wavenumbers and intensities of IR as well as chemical shifts in NMR spectra were obtained and compared with experimental data. The effect of alkali metals on molecular structure of phenoxyacetic acid appears in the shift of selected bands along the series of alkali metal salts. The correlations between chosen bands and some metal parameters, such as electronegativity, ionization energy, and atomic, and ionic radius, have been noticed.

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.

Charge Reduction of Membrane Proteins in Native Mass Spectrometry Using Alkali Metal Acetate Salts

2019 ◽  
Author(s):  
John T. Petroff II ◽  
Ailing Tong ◽  
Lawrence Chen ◽  
GregoryT. DeKoster ◽  
Farha Khan ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Membrane Proteins ◽  
Alkali Metal ◽  
Conformational Changes ◽  
Alkali Metals ◽  
Native Mass Spectrometry ◽  
Metal Salts ◽  
Charge Reduction ◽  
Alkali Metal Salts ◽  
Metal Acetate

<p>Native mass spectrometry paired with ion mobility (IM-MS) provides the capacity to monitor the structure of protein complexes and simultaneously assess small molecule binding to the protein. Native IM-MS typically utilizes positive mode electrospray ionization producing a distribution of multiply charged protein species. For membrane proteins, these charge states are often too high resulting in protein gas phase unfolding or loss of noncovalent interactions. In an effort to reduce the charge of membrane proteins, the utility of alkali metal salts as a charge reducing additive was explored. Low concentrations of alkali metal salts caused marked charge reduction in the membrane protein, ELIC. The charge reducing effect was only present in membrane proteins, and could not be accounted for by conformational changes in ELIC structure. Charge reduction by alkali metal salts was also detergent dependent, and was most pronounced in long PEG-based detergents such as C10E5 and C12E8. Based on these results, a mechanism was posited for alkali metal charge reduction of membrane proteins. Addition of low concentration of alkali metals may provide an advantageous approach for charge reduction of detergent solubilized membrane proteins by native MS. <br></p>

Charge Reduction of Membrane Proteins in Native Mass Spectrometry Using Alkali Metal Acetate Salts

2019 ◽  
Author(s):  
John T. Petroff II ◽  
Ailing Tong ◽  
Lawrence Chen ◽  
GregoryT. DeKoster ◽  
Farha Khan ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Membrane Proteins ◽  
Alkali Metal ◽  
Conformational Changes ◽  
Alkali Metals ◽  
Native Mass Spectrometry ◽  
Metal Salts ◽  
Charge Reduction ◽  
Alkali Metal Salts ◽  
Metal Acetate

<p>Native mass spectrometry paired with ion mobility (IM-MS) provides the capacity to monitor the structure of protein complexes and simultaneously assess small molecule binding to the protein. Native IM-MS typically utilizes positive mode electrospray ionization producing a distribution of multiply charged protein species. For membrane proteins, these charge states are often too high resulting in protein gas phase unfolding or loss of noncovalent interactions. In an effort to reduce the charge of membrane proteins, the utility of alkali metal salts as a charge reducing additive was explored. Low concentrations of alkali metal salts caused marked charge reduction in the membrane protein, ELIC. The charge reducing effect was only present in membrane proteins, and could not be accounted for by conformational changes in ELIC structure. Charge reduction by alkali metal salts was also detergent dependent, and was most pronounced in long PEG-based detergents such as C10E5 and C12E8. Based on these results, a mechanism was posited for alkali metal charge reduction of membrane proteins. Addition of low concentration of alkali metals may provide an advantageous approach for charge reduction of detergent solubilized membrane proteins by native MS. <br></p>

Studies on the ionization produced by metallic salt in flames - III. Ionic equilibria in hydrogen/air flames containing alkali metal salts

1952 ◽  
Vol 211 (1104) ◽  
pp. 31-58 ◽  
Keyword(s):  
Alkali Metal ◽  
Resonant Frequency ◽  
Electron Concentration ◽  
Alkali Metals ◽  
Ionic Species ◽  
Molecular Ions ◽  
Metal Salts ◽  
Temperature Inhomogeneity ◽  
Alkali Metal Salts ◽  
Hydroxyl Ion

An examination has been made of the electron concentration produced when alkali metal salts are added to various hydrogen/air flames containing excess hydrogen. The results have shown that although the variation of the measured electron concentration with the concentration of added alkali metal shows the thermodynamically predicted behaviour, the variation with respect to flame temperature and ionization potential of alkali metal is very different from that predicted by theory, Coupled with this, there is a serious discrepancy between the measured and predicted levels of electron concentration, the former being much too low. The electron concentrations were measured by the attenuation of centimetric radio waves by the flame, and the temperatures by the sodium D -line reversal method. Since the flames contain a fair proportion of hydroxyl radicals (of the order of 01 %) in the regions studied, i.e. the zone of hot gases succeeding the cones of primary combustion in the burner, the formation of negative hydroxyl ions in considerable quantity appeared to be a plausible explanation of some of the observed discrepancies. An experimental method has been devised for the estimation of the atomic and molecular ions (other than electrons) in flames by making the flame form a portion of the dielectric of a simple parallel-plate condenser. The relative effects of the electrical conductivity, due mainly to the electrons, and the dielectric constant, which is affected to a large extent by the other ionic species at frequencies of the order of 100 Mc/s, on the resonant frequency and selectivity of a simple circuit containing this flame capacity, allow of an analysis for the electrons and massive ions respectively. In the absence of the massive ions, the resonant frequency shift and selectivity change induced by the flame should show parallel effects, but if massive ions are present in sufficient concentration, they show themselves by a marked effect on the resonant frequency and little effect on the selectivity. From the observations made the presence of such massive ions in these flames was inferred. An important preliminary step was to ensure that the concentrations of electrons which could be deduced from both the attenuation and capacity methods were in agreement. It has been shown that this will not be so unless the flames used are uniform in the sense of their cross-sectional temperatures. The required agreement was obtained when such flames were used, entrainment of air with production of temperature inhomogeneity being prevented by sheathing the flame with a stream of nitrogen. Measurement of the temperature distribution in unsheathed flames, and application of a simple mathematical analysis, given in the appendix, to these distributions, also brought about agreement for electron concentration. These sheathed flames gave a variation of electron concentration more consistent with the predicted relative behaviour for different alkali metals, although the temperatures deduced were several hundred degrees above the measured ones. Analysis of the heavier ion concentrations from the results indicated in general about twenty times as many as there were electrons. These were divided, to give charge balance, between positive alkali metal ions and OH- , these being the only reasonable ionic species for these flames. Incorporation of this hydroxyl ion effect largely removes the discrepancy between the measured and predicted absolute electron concentration. The results lead to a reasonable value of the collision frequency of a heavy ion with molecules, and, combined with the theoretical hydroxyl concentrations for the flame, suggest a value for the electron affinity of hydroxyl of 62 ± 6 kcal/mole. This value is reasonable by comparison with those for the halogens.

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