scholarly journals EVALUATION OF ION ASSOCIATION AND THERMODYNAMIC PARAMETERS OF METHYL BIS-1-AMIDINO-O-MEHTYLUREA NICKEL (II) HALIDES IN WATER AT DIFFERENT TEMPERATURES

2014 ◽  
Author(s):  
N. M. Singh Lalrosanga N. M. Singh Lalrosanga ◽  
Keyword(s):  
Thermodynamic Parameters ◽  
Ion Association ◽  
Different Temperatures

scholarly journals Thermodynamic and detailed kinetic study of the formation of orthophthalaldehyde-agmatine complex by fluorescence intensities

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Khémesse Kital ◽  
Moumouny Traoré ◽  
Diégane Sarr ◽  
Moussa Mbaye ◽  
Mame Diabou Gaye Seye ◽  
...  
Keyword(s):  
Complex Formation ◽  
Thermodynamic Parameters ◽  
Initial Rate ◽  
Reaction Medium ◽  
Standard Entropy ◽  
Step Size ◽  
Formation Reaction ◽  
Different Temperatures ◽  
Kinetics Of ◽  
Complex Formation Process

Abstract The aim of this work is to determine the thermodynamic parameters and the kinetics of complex formation between orthophthalaldehyde (OPA) and agmatine (AGM) in an alkaline medium (pH 13). Firstly, the association constant (Ka) between orthophthalaldehyde and agmatine was determined at different temperatures (between 298 K and 338 K) with a step size of 10 K. Secondly, the thermodynamic parameters such as standard enthalpy (ΔH°), standard entropy (ΔS°),and Gibbs energy (∆G) were calculated, where a positive value of ΔH° (+45.50 kJ/mol) was found, which shows that the reaction is endothermic. In addition, the low value of ΔS°(+0.24 kJ/mol) indicates a slight increase in the disorder in the reaction medium. Furthermore, the negative values of ΔG between −35.62 kJ/mol and −26.02 kJ/mol show that the complex formation process is spontaneous. Finally, the parameters of the kinetics of the reaction between OPA and AGM were determined as follows: when the initial concentration of AGM (5 × 10−6 M) is equal to that of the OPA, the results show that the reaction follows an overall 1.5 order kinetics with an initial rate of 5.1 × 10−7Mmin−1 and a half-life of 8.12 min. The partial order found in relation to the AGM is 0.8. This work shows that the excess of OPA accelerates the formation reaction of the complex.

scholarly journals Thermodynamic studies of substrate binding and spin transitions in human cytochrome P-450 3A4 expressed in yeast microsomes

1996 ◽  
Vol 319 (3) ◽  
pp. 675-681 ◽  
Author(s):  
Jean-Paul RENAUD ◽  
Dmitri R. DAVYDOV ◽  
Karel P. M. HEIRWEGH ◽  
Daniel MANSUY ◽  
Gaston HUI BON HOA
Keyword(s):  
Thermodynamic Parameters ◽  
Protein Interactions ◽  
Substrate Binding ◽  
Principal Component ◽  
Yeast Saccharomyces Cerevisiae ◽  
Human Cytochrome ◽  
Different Temperatures ◽  
Haem Protein ◽  
Cytochrome P 450 ◽  
Spin Transitions

An approach to the quantitative spectral analysis of substrate binding and inactivation of cytochrome P-450 in microsomes is described. The method is based on the application of the principal component analysis technique on the Soret-region spectra measured at different temperatures at various concentrations of substrate. This approach allowed us to study the thermodynamic parameters of substrate binding and spin transitions in human cytochrome P-450 3A4 expressed in yeast (Saccharomyces cerevisiae) microsomes. These parameters are discussed in comparison with the values reported earlier by Ristau et al. [(1979) Acta Biol. Med. Ger. 38, 177–185] for rabbit liver cytochrome P-450 2B4 in solution with benzphetamine as a substrate. Our analysis shows the substrate-free states of 2B4 and 3A4 to be very similar. However, substrate binding seems to perturb haem-protein interactions in 3A4 in contrast with 2B4, where the effect of substrate binding on the thermodynamic parameters of spin transitions was insignificant. The implication of the results for the mechanism of substrate-induced spin shift is discussed.

scholarly journals Conductometric studies of 1, 3, 5 –triazinothiocarbamide at different concentration and temperature

2021 ◽  
Vol 16 (2) ◽  
pp. 151-157
Author(s):  
DD Sonone ◽  
ME Shelke ◽  
DT Tayade
Keyword(s):  
Thermodynamic Parameters ◽  
Association Constant ◽  
Ion Association ◽  
Vital Role ◽  
Ion Pair ◽  
Pair Formation ◽  
Drug Diffusion ◽  
Ion Pair Formation

Conductivity plays vital role in drug diffusion. Thermodynamic parameters affected by substituents of drug. Thermodynamic parameters of 1, 3, 5 –triazinothiocarbamide (1a) have been investigated by using conductometrically carried out at different molar concentrations. This work highlights investigation of G, K and µ values. The thermodynamic parameters viz. ΔH, ΔS and ∆G for ion pair formation determine from the value of ion association constant. This technique is suitable and accurate to study of pharmokinetics and pharmodynamics parameters.

Thermodynamic parameters for the protonation of urea at different temperatures and ionic strengths

1992 ◽  
Vol 21 (4) ◽  
pp. 397-404 ◽  
Author(s):  
Concetta De Stefano ◽  
Antonino Famá ◽  
Giuseppe Salvo
Keyword(s):  
Thermodynamic Parameters ◽  
Different Temperatures

scholarly journals The Effect of Sodium Chloride on Ion Association of Lysine and Arginine Ionizable Side Chains Amino Acids with Dehydro-L-ascorbic Acid in Aqueous Solution at Different Temperatures

2019 ◽  
pp. 1412-1422
Author(s):  
Muhammed J. Kadhim
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Amino Acids ◽  
Exothermic Reaction ◽  
Dehydroascorbic Acid ◽  
Ion Association ◽  
Molar Conductance ◽  
Einstein Relation ◽  
Side Chains ◽  
Different Temperatures

Molar conductance (Λ) of ionizable side chains amino acids, lysine (Lys) and arginine (Arg) with dehydroascorbic acid (DHA) in water and in NaCl solutions was measured at temperatures range 298 K to 313 K. The limited molar conductance (Λo) and the constant of the ions association (KA) are calculated using the Shedlovsky techniques. The dynamic radius of the concerned ion (R) is calculated by used Stokes–Einstein relation. The heat of association, the Gibbs free energy, the change of entropy and activation energy (ΔHo/ kJ mol-1, ΔGo/ kJ mol-1, ΔSo/J K-1 mol-1, and ΔES/ kJ mol-1) respectively), also calculated. The data show increases the molar conductance with increase in temperature and decreasing in values at addition of DHA to Lys and Arg solutions. The association ions in NaCl solutions appear to increase in radius and decrease in diffusion coefficient relative to water solutions.ΔES, shows in most samples a positive value for the association and the values in NaCl solutions has lower relative to the water solutions. ΔGo is a trend to decrease with an increase in DHA concentration in water and NaCl solutions. The ion association is exothermic reaction relative to the negative value of ΔHo. The ΔSo andΔHo results, for Lys and Arg solutions, show decreasing in values at increase in DHA concentration in water and NaCl solutions. ΔGo (kJ mol-1), ΔSo (J K-1 mol-1), Î”Ho (kJ mol-1), and ΔEs (kJ mol-1) 

scholarly journals Thermodynamic Studies on Ion Association of Lithium Chloride and Lithium Nitrate in Acetonitrile + Water Mixed Solvents at Different Temperatures

2021 ◽  
Vol 34 (1) ◽  
pp. 230-234
Author(s):  
Lalrosanga ◽  
N. Mohondas Singh
Keyword(s):  
Lithium Chloride ◽  
Mixed Solvents ◽  
Ion Association ◽  
Molar Conductance ◽  
Lithium Nitrate ◽  
Mixed Composition ◽  
Water Solvent ◽  
Limiting Molar Conductance ◽  
Different Temperatures ◽  
Walden Products

The present study reports the ion association of lithium chloride (LiCl) and lithium nitrate (LiNO3) electrolytes in acetonitrile + water (AN+W) mixtures at 283.15 K to 311.15 K. Their limiting molar conductance (Λo), the association constant values (KA) for their different mole fractions, i.e. 0.0000, 0.0588, 0.1233, 0.1942, 0.2727, 0.3600, 0.4576, 0.5676, 0.6923, 0.8351 and 1.0000 have been evaluated using Shedlovsky technique. The KA and Walden products (Λoηo) for LiCl and LiNO3 salts have been calculated in the acetonitrile-water solvent at experimental temperatures. The calculated values qualitatively examined the possible nature of the solvent-solvent, their ion-ion, and ion-solvent and interactions of the two selected compounds mixed solvents of (acetonitrile + water). Then dependence of KA temperature has also been investigated to obtain the thermodynamic functions of different parameters, such as ΔGº, ΔSº, ΔHº and Ea, as a function of the mixed composition of the composition solvents AN+W (acetonitrile + water).

Transport Behaviour of Ions in N,N-Dimethylformamide and Dimethyl Sulfoxide at Different Temperatures. Conductance Studies

1995 ◽  
Vol 60 (1) ◽  
pp. 43-54 ◽  
Author(s):  
Mohinder S. Chauhan ◽  
Manita Sharma ◽  
Sanjay Gupta ◽  
K. Ashwini ◽  
Suvarcha Chauhan
Keyword(s):  
Association Constant ◽  
Ion Association ◽  
Dipole Interaction ◽  
Molar Conductivity ◽  
Specific Interactions ◽  
Ionic Radii ◽  
Conductance Data ◽  
Different Temperatures ◽  
Transport Behaviour ◽  
Ionic Components

Molar conductivities of Bu4NBPh4, Bu4NNO3, LiNO3, NaNO3, KNO3 and AgNO3 have been reported in pure DMF and DMSO in the temperature range from 20 to 45 °C. The conductance data have been analyzed in terms of limiting molar conductivity Λ0 and ion-association constant KA. Separation of Λ0 into ionic components Λi 0 has been carried out on the basis of Bu4NBPh4 assumption in order to calculate the effective ionic radii ri in DMF and DMSO. Examination of ri values of K+ and Ag+ ions as a function of temperature revealed some specific interactions of Ag+ ion with DMF and DMSO. In DMSO electrostatic ion-dipole interaction of Li+, Na+ and K+ ions is found to be somewhat modified due to dipole-dipole interaction.

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