Acid Dissociation Constant, Formation Constant, Enthalpy, and Entropy Values for Some Copper(II)-α-Amino Acid Systems in Aqueous Solution

1964 ◽  
Vol 3 (11) ◽  
pp. 1565-1567 ◽  
Author(s):  
Reed M. Izatt ◽  
James J. Christensen ◽  
Vipin Kothari
Keyword(s):  
Aqueous Solution ◽  
Amino Acid ◽  
Dissociation Constant ◽  
Formation Constant ◽  
Acid Dissociation ◽  
Acid Dissociation Constant ◽  
Enthalpy And Entropy

scholarly journals A QSPR Study for the Prediction of the pKa of N-Base Ligands and Formation Constant Kc of Bis(2,2′-bipyridine)Platinum(II)-N-Base Adducts Using Quantum Mechanically Derived Descriptors

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Selami Palaz ◽  
Baki Türkkan ◽  
Erol Eroğlu
Keyword(s):  
Linear Equation ◽  
Dissociation Constant ◽  
Correlation Coefficient ◽  
Formation Constant ◽  
Acid Dissociation ◽  
Reactivity Index ◽  
Acid Dissociation Constant ◽  
Am1 Calculations ◽  
Qspr Model ◽  
Qspr Study

Quantitative structure-property relationship (QSPR) study on the acid dissociation constant, pKa of various 22 N-base ligands including pyridines, pyrimidines, purines, and quinolines has been carried out using Codessa Pro methodology and software. In addition, the formation constant, Kc of these ligands with Pt(II)(bpy)2 2+ (bpy = 2,2′-bipyridine) ion has also been modelled with the same methodology. Linear regression QSPR models of pKa and Kc were established with descriptors derived from AM1 calculations. Among the obtained QSPR models of pKa presented in the study, statistically the most significant one is a four parameters linear equation with the squared correlation coefficient, R2 values of ca. 0.95 and the squared cross-validated correlation coefficient, Rcv2 values of ca. 0.89, and external the squared correlation coefficient, Rext.2 values of ca. 0.97. Statistically the most significant QSPR model of Kc is also a four parameters linear equation with the squared correlation coefficient, R2 values of ca. 0.75 and the squared cross-validated correlation coefficient, Rcv2 values of ca. 0.55, and external the squared correlation coefficient, Rext.2 values of ca. 0.81. An analysis of descriptors that involved in the pKa models indicate that reactivity index and charge distribution related descriptors play major roles to model acid dissociation constant of ligands of N bases.

Early Stages of the Hydrolysis of Chromium(III) in Aqueous Solution. V. Measurement of the Equilibrium Between Singly and Doubly Bridged Dimer

1989 ◽  
Vol 42 (9) ◽  
pp. 1579 ◽  
Author(s):  
T Merakis ◽  
L Spiccia
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Bonding ◽  
Ion Exchange ◽  
Dissociation Constant ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Acid Dissociation ◽  
Acid Dissociation Constant ◽  
Thermodynamic Constants ◽  
Hydrolysis Of

Ion-exchange chromatography has been used to measure the equilibrium between singly bridged (SBD) and doubly bridged (DBD) forms of the hydrolytic dimer of chromium(III), at variable [H+] (0.008-0.97 M) and T (288.2-318.2 K) and constant I (1.0 M). From these measurements, the acid dissociation constant, Kal , for SBD, and the equilibrium constant, K, for interconversion between monodeprotonated SBD and DBD have been determined together with their corresponding thermodynamic constants. The results at 298.2K were as follows: K = 10.1( �0.6) [ΔH� = -10( �3) kJ mol-1 and ΔS�=-15( �9) J K-1 mol-1]; KKal = 1 .83(�0.04) mol dm-3 [ΔS� = 30(�1) kJ mol-1 and ΔS�= 104(�4) J K-1 mol-1]; Kal = 0.18( �0.2) mol dm-3 [ΔS�= 43(�4) kJ mol-l and ΔS�= 128(�13) J K-1 mol-1]. The high Kalis attributed to the participation of monodeprotonated SBD in hydrogen bonding. As the temperature increases, the overall equilibrium (given by KKal ) is driven towards DBD by a dramatic increase in the acidity ( Kal ) of SBD, an increase which more than offsets a concurrent decrease in K.

Determination of the Acid Dissociation Constant of the Biosurfactant Monorhamnolipid in Aqueous Solution by Potentiometric and Spectroscopic Methods

2006 ◽  
Vol 78 (22) ◽  
pp. 7649-7658 ◽  
Author(s):  
Ariel Lebrón-Paler ◽  
Jeanne E. Pemberton ◽  
Bridget A. Becker ◽  
William H. Otto ◽  
Cynthia K. Larive ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Dissociation Constant ◽  
Acid Dissociation ◽  
Spectroscopic Methods ◽  
Acid Dissociation Constant

Accurate acid dissociation constant (pKa) calculation for the sulfachloropyridazine and similar molecules

2021 ◽  
Vol 27 (8) ◽  
Author(s):  
Fernando Marques Carvalho ◽  
Yuri Alves de Oliveira Só ◽  
Alessandra Sofia Kiametis Wernik ◽  
Mônica de Abreu Silva ◽  
Ricardo Gargano
Keyword(s):  
Dissociation Constant ◽  
Acid Dissociation ◽  
Acid Dissociation Constant ◽  
Pka Calculation

scholarly journals pKa and Ka (Acid dissociation constant)

2020 ◽  
pp. S108-S108
Author(s):  
G Manjooran
Keyword(s):  
Dissociation Constant ◽  
Acid Dissociation ◽  
Acid Dissociation Constant

pKa of a drug is the pH at which 50% of the drug is ionised and 50% is not ionised/unionised. The pKa is specific for each drug and these properties determine how a drug can be administered, the speed of absorption as well as speed of excretion by the kidneys.

Conductometric analysis of the second acid dissociation constant of H2S in highly concentrated aqueous media

1991 ◽  
Vol 318 (1-2) ◽  
pp. 111-129 ◽  
Author(s):  
Stuart Licht ◽  
Kevin Longo ◽  
Dharmasena Peramunage ◽  
Fardad Forouzan
Keyword(s):  
Dissociation Constant ◽  
Aqueous Media ◽  
Acid Dissociation ◽  
Acid Dissociation Constant
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