Hydroxide Ion Hydration in Aqueous Solutions

2007 ◽  
Vol 111 (15) ◽  
pp. 2889-2897 ◽  
Author(s):  
Maciej Śmiechowski ◽  
Janusz Stangret
Keyword(s):  
Aqueous Solutions ◽  
Ion Hydration ◽  
Hydroxide Ion

scholarly journals Comparison of methods for solving the vibrational Schrödinger equation in the course of sequential Monte-Carlo-quantum mechanical treatment of hydroxide ion hydration

2010 ◽  
Vol 29 (2) ◽  
pp. 203
Author(s):  
Jasmina Petreska ◽  
Ljupco Pejov
Keyword(s):  
Sequential Monte Carlo ◽  
Reference Method ◽  
Hamiltonian Matrix ◽  
Ion Hydration ◽  
Hydroxide Ion ◽  
Frequency Shifts ◽  
One Dimensional ◽  
Quantum Mechanical Treatment ◽  
Wide Range ◽  
Matrix Diagonalization

Three numerical methods were applied to compute the anharmonic O–H stretching vibrational frequencies of the free and aqueous hydroxide ion on the basis of one-dimensional vibrational potential energies computed at various levels of theory: i) simple Hamiltonian matrix diagonalization technique, based on representation of the vibrational potential in Simons-Parr-Finlan (SPF) coordinates, ii) Numerov algorithm and iii) Fourier grid Hamiltonian method (FGH).Considering the Numerov algorithm as a reference method, the diagonalization technique performs remarkably well in a very wide range of frequencies and frequency shifts (up to 300 cm–1). FGH method, on the other hand, though showing a very good performance as well, exhibits more significant (and non-uniform) discrepancies with the Numerov algorithm, even for rather modest frequency shifts.

Reactions of 1,?-bis(2-bromopyridinium)alkanes with hydroxide ion in aqueous solutions

1998 ◽  
Vol 11 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Carmen Fernandez ◽  
Vicente G. Toscano ◽  
Hernan Chaimovich ◽  
Mario J. Politi ◽  
Noboru Hioka
Keyword(s):  
Aqueous Solutions ◽  
Hydroxide Ion

Ion Hydration Under Pressure: A Molecular Dynamics Study

2013 ◽  
Vol 68 (1-2) ◽  
pp. 112-122 ◽  
Author(s):  
Maksym Druchok ◽  
Myroslav Holovko
Keyword(s):  
Molecular Dynamics ◽  
Aqueous Solutions ◽  
Dynamic Properties ◽  
Ion Hydration ◽  
Coordination Numbers ◽  
Self Diffusion ◽  
Velocity Autocorrelation ◽  
Hydration Behaviour ◽  
Hydration Shells ◽  
Dynamics Simulations

This study is intended to elucidate the role of pressure on the hydration behaviour of ions in aqueous solutions. Molecular dynamics simulations were performed for systems modelling CsF, CsCl, CsBr, and CsI aqueous solutions under ‘normal’ (105 Pa, 298 K) and ‘high pressure’ (4 ·109 Pa, 500 K) conditions. Structural details are discussed in terms of radial distributions functions, coordination numbers, and instantaneous configurations of the ionic hydration shells. The dynamic properties studied include the velocity autocorrelation functions and self-diffusion coefficients of the ions for both pressure regimes. The results indicate strong changes in the hydration behaviour and mobility of the ions.

Thermodynamic and kinetic acidities of N-(substituted benzyl) 4-phenylacetylpyridinium cations in aqueous solution

1991 ◽  
Vol 69 (6) ◽  
pp. 945-948 ◽  
Author(s):  
John W. Bunting ◽  
P. Philippe Aubin
Keyword(s):  
Aqueous Solutions ◽  
Substituent Effects ◽  
Order Rate Constant ◽  
Hydroxide Ion ◽  
Subsequent Transformation ◽  
Order Rate ◽  
Carbon Acids ◽  
Pyridinium Cations ◽  
Saturation Effects ◽  
Conjugate Base

The pKa values for the deprotonation of a series of eight 1-(X-benzyl)-4-phenylacetylpyridinium cations (6) have been measured in aqueous solutions of ionic strength 0.1 at 25 °C: pKa = −0.18σ + 8.91. The pseudo-first-order rate constants for deprotonation of these carbon acids have been measured over the range pH = 11–13, and have been found to display kinetic saturation effects that are consistent with the addition of hydroxide ion to the carbonyl group (pKz) as the product of kinetic control upon basification of neutral aqueous solutions of these pyridinium cations, with the subsequent transformation of this anionic hydrate to the thermodynamically more stable enolate conjugate base. Analysis of the pH–rate profiles gives substituent effects upon pKz (ρ = −0.19) and upon the second-order rate constant (kOH (ρ = 0.09)) for deprotonation of 6 by hydroxide ion. Key words: carbon acids, deprotonation, pKa, kinetics, substituent effects.

Protein and ion hydration variation in fixed aqueous solutions: measurement by dielectric decrement

1985 ◽  
Vol 30 (8) ◽  
pp. 831-837 ◽  
Author(s):  
A Rejou-Michel ◽  
F Henry ◽  
M de Villardi ◽  
M Delmotte
Keyword(s):  
Aqueous Solutions ◽  
Ion Hydration

Rate constants for the addition of the enolate ion of acetone to quinolinium and acridinium cations

1990 ◽  
Vol 68 (10) ◽  
pp. 1762-1768 ◽  
Author(s):  
John W. Bunting ◽  
Cynthia Fu ◽  
James W. Tam
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Rate Constants ◽  
Nucleophilic Addition ◽  
Ph Dependence ◽  
Adduct Formation ◽  
Kinetic Control ◽  
Thermodynamic Control ◽  
Hydroxide Ion ◽  
Kinetically Controlled

The reaction of acetone with four heteroaromatic cations (10-methylacridinium (1), 3-aminocarbonyl-1-methylquinolinium (2a), 3-cyano-1-methylquinolinium (2b), and 3-bromo-1-methylquinolinium (2c)) has been investigated in basic aqueous solutions (pH 9–12, ionic strength 0.1, 25 °C). For each of 2a and 2b, the kinetically controlled product is a 35:65 mixture of the C-2 and C-4 enolate ion adducts; the C-2 adduct subsequently isomerizes to give the C-4 adduct as the only observable species under thermodynamic control. For 2c, the C-2 enolate adduct appears to be favoured both kinetically and thermodynamically. Under kinetic control, the pH-dependence of adduct formation from each cation is consistent with rate-determining attack of the enolate ion upon the heterocyclic cation. Comparisons of regiochemical control of acetone enolate ion attack with hydroxide ion attack upon these same cations indicate that acetone enolate ion shows a more pronounced preference for C-4 attack over C-2 attack than does hydroxide ion. The thermodynamically controlled regiochemistry is similar for each of these two nucleophiles. Keywords: nucleophilic addition, regioselectivity, kinetic control, thermodynamic control, quinolinium cations.

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