Synthesis and Structure of a Novel Substituted Benzothiazolyl-N-phenyl-2-pyridinecarbothioamide; Kinetics of Formation and Electrochemistry of Two of its Palladium Pincer Complexes

2015 ◽  
Vol 68 (5) ◽  
pp. 731 ◽  
Author(s):  
Mark A.W. Lawrence ◽  
Yvette A. Jackson ◽  
Willem H. Mulder ◽  
Per Martin Björemark ◽  
Mikael Håkansson
Keyword(s):  
Complex Formation ◽  
Stability Constant ◽  
Palladium Complex ◽  
Coordination Complexes ◽  
Pincer Complexes ◽  
Kinetics Of Formation ◽  
Acetonitrile Solutions ◽  
The Stability ◽  
Electron Transfers ◽  
Kinetics Of

The synthesis and crystal structures of bis-N-(2,5-dimethoxyphenyl)pyridine-2,6-dicarbothioamide (dicarbothioamide I) and 6-(4,7-dimethoxy-2-benzothiazolyl)-N-(2,5-dimethoxyphenyl)-2-pyridinecarbothioamide (L1) as well as the syntheses of the palladium(ii) chloride and acetate pincer complexes are reported. The stability constant for the palladium complex formation at 25°C was found to be (2.04 ± 0.26) × 104 dm3 mol–1 and (2.30 ± 0.19) × 104 dm3 mol–1 with ΔfH = 8 ± 1 kJ mol–1, ΔfSθ = 108 ± 10 J K–1 mol–1, and ΔfH = 17 ± 4 kJ mol–1 and ΔfSθ = 140 ± 20 J K–1 mol–1 for the PdClL1 and Pd(OAc)L1, respectively. The kinetics of formation of the palladium(ii) complexes were investigated and the mechanism is proposed to be associative in nature (ΔH1‡ = 34 ± 2 kJ mol–1 and ΔS1‡ = –113 ± 8 J K–1 mol–1, and ΔH1‡ = 37 ± 3 kJ mol–1 and ΔS1‡ = –100 ± 8 J K–1 mol–1 for the PdClL1 and Pd(OAc)L1 species, respectively). The electrochemical measurements of the acetonitrile solutions revealed irreversible electron transfers consistent with the electrochemical decomposition of the ligand and its coordination complexes.

scholarly journals Modeling and Thermodynamic Values of Complex Equilibrium of Cobalt(II) with Diethylenetriaminepentaacetic Acid in Aqueous Solution

2021 ◽  
Author(s):  
Ghusoon Faidhi Hameed ◽  
Fawzi Yahya Waddai ◽  
Nahla Shakir Salman
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Complex Formation ◽  
Stability Constant ◽  
Wide Spectrum ◽  
Equilibrium Constants ◽  
Diethylenetriaminepentaacetic Acid ◽  
The Stability ◽  
Hoff Equation ◽  
Potentiometric Data

The paper reports the study of the complex formation of cobalt (II) with diethylenetriaminepentaacetic acid (DTPA, H5L) based on spectrophotometric (SF) and potentiometric data (pH). Complexes of different compositions were found, and equilibrium constants, as well as the stability constants of these complexes, were determined. Accumulation of complexes in proportion is calculated based on the acidity of the medium. The experimental data have been carried out by using mathematical models to assess the solution's possible existence with a wide spectrum of complex particles and to point out those which are quite sufficient to copy the experimental data. In addition, thermodynamic parameters (ΔG°, ΔH°, and ΔS°) for the studying complexes were calculated according to the values of stability constant (KST) at 25 °C obtained from the temperature dependence of stability constant by using van’t Hoff equation.

Kinetics of formation and the stability of paramagnetic particles which appear during adsorption of anthracene on aluminosilicates

1973 ◽  
Vol 6 (5) ◽  
pp. 541-544
Author(s):  
M. N. Zhavoronkov ◽  
E. N. Rosolovskaya ◽  
K. V. Topchieva ◽  
V. B. Golubev
Keyword(s):  
Kinetics Of Formation ◽  
The Stability ◽  
Kinetics Of

scholarly journals Conductometric Study of Complex Formation Between Cu(II) Ion and 4-Amino-3-ethyl-1,2,4-triazol-5-thione in Binary Ethanol / Water Mixtures

2008 ◽  
Vol 5 (3) ◽  
pp. 551-556 ◽  
Author(s):  
Mohammad Hakimi ◽  
Azizollah Nezhadali ◽  
Asghar Naemi
Keyword(s):  
Dielectric Constant ◽  
Complex Formation ◽  
Stability Constant ◽  
Formation Constant ◽  
Stability Constants Of Complexes ◽  
Conductometric Study ◽  
Entropy Of Complexation ◽  
Enthalpy And Entropy ◽  
The Stability ◽  
Complexation Process

The stability constant, Kf, for the complexation of copper(II) ion with 4-amino-3-ethyl-1,2,4-triazol-5-thione (AETT ) in 0, 20, 40, 60 and 80 (v/v) % ethanol-water mixtures were determined conductometrically at different tempratures. Stability constant of resulting 1:1 complexes were being larger by increasing of temprature and ethanol percent. Stability constants of complexes vary inversly with dielectric constant of solvents. The enthalpy and entropy of complexation were determined from the temprature dependence of the formation constant. In all cases, the complexation were found to be enthalpy unstablized but entropy stablized. ࢞G0of the studied complexes were evaluated at 25°C using thermodynamic relations, the negative values of ࢞G0means that the complexation process is spantaneously.

scholarly journals Reaction kinetics and macromolecule-metal chelate complex formation in metal containing semi-interpenetrating polymer networks based on crosslinked polyurethane and linear polymethylmethacrylate

2008 ◽  
Vol 2 (4) ◽  
pp. 263-270
Author(s):  
Ludmila Kosyanchuk ◽  
◽  
Nataly Kozak ◽  
Oksana Antonenko ◽  
Yury Nizelskii ◽  
...  
Keyword(s):  
Complex Formation ◽  
Reaction Kinetics ◽  
Metal Chelate ◽  
Polymer Networks ◽  
Interpenetrating Polymer Networks ◽  
The Other ◽  
System Composition ◽  
Kinetics Of Formation ◽  
Kinetics Of ◽  
Formation Of Complexes

According to DSC and EPR data kinetics of formation of simultaneous semi-interpenetrating polymer networks based on crosslinked polyurethane and linear polymethylmethacrylate with 50:50 and 70:30 ratio obtained in the presence of 3d-metal chelates depends on type of metal. On the other hand system composition determines polyurethane or polymethylmethacrylate selection during formation of complexes with metal -diketonates.

On the Twin Formation in Orthorhombic Y1Ba2Cu3O7-Y

1987 ◽  
Vol 99 ◽  
Author(s):  
D. Rios-Jara ◽  
C. Varea ◽  
A. Robledo ◽  
A. Huanosta ◽  
J. M. Dominguez ◽  
...  
Keyword(s):  
Oxygen Content ◽  
Orthorhombic Phase ◽  
Electron Energy Loss Spectrometry ◽  
Relative Value ◽  
Kinetics Of Formation ◽  
Twin Formation ◽  
The Stability ◽  
Electron Energy Loss ◽  
Kinetics Of ◽  
Scanning Electron

ABSTRACTTransmission and scanning electron microscopy were used to study some features of twins in the orthorhombic phase of Y1Ba2Cu3O7-Y compounds. A model that explains the formation and proliferation of thene defectr, is proposed. Some conclusions about the kinetics of formation of these defects are stated, which agree with observed changes in twin densities produced by different cooling rates. Electron energy loss spectrometry (EELS) was ucod to measure relative changes in oxygen, which give some information about the relative value and the stability of oxygen content in twinned regions. A Braggs-Williams model of the order-disorder transition, for oxygen occupancies in the Cu-O2 planes, predicts an enrichment of vacancies at the boundaries in these oxygen deficient perovskites. This could explain the observed deficiency in oxygen content with respect to the perfect Y1Ba2Cu3O7 stoichio-metry.

The formation of hydroxy and chloro complexes of iron(III) in chloride and perchlorate media

1969 ◽  
Vol 22 (6) ◽  
pp. 1111 ◽  
Author(s):  
AW Fordham
Keyword(s):  
Ionic Strength ◽  
Complex Formation ◽  
Stability Constant ◽  
Experimental Error ◽  
Chloride Ions ◽  
Chloro Complexes ◽  
Spectrophotometric Methods ◽  
Hydrolysis Constants ◽  
The Stability ◽  
Hydrolysis Of

The hydrolysis of iron(III) has been studied by spectrophotometric methods in KaClO4, NaCl, and CaCl2 solutions all of the same ionic strength 0.15M. The measured values of the hydrolysis constants, expressed in a form which allows for association of iron with the supporting medium, were 14.5 x 10-4 in NaClO4, 8.8 x 10-4 in NaCl, and 10.9 x 10-4 in CaCl2. In addition, the extent of complex formation between iron(III) and chloride ions has been measured in perchlorate solutions of the same ionic strength 0.15M. Assuming that only chloro complexes were formed in these systems, the stability constant of FeCl2+ formation was found to be 4.0. ��� All the results obtained were sufficiently consistent with each other, within experimental error, that the inclusion of terms to account for iron-perchlorate association was unwarranted. However, if iron-perchlorate association was assumed to exist and the results were treated accordingly, the stability constant of the associated complex was estimated to be 1.8.

scholarly journals ASPECTOS GERAIS DA QUÍMICA DOS DITIOCARBAMATOS E DE SEUS COMPLEXOS METÁLICOS E INTERAÇÕES DESSAS ESPÉCIES QUÍMICAS COM IMPORTANTES ENZIMAS – UMA BREVE REVISÃO

Química Nova ◽  
2021 ◽  
Author(s):  
Daniele Menezes ◽  
Geraldo Lima
Keyword(s):  
Superoxide Dismutase ◽  
Coordination Chemistry ◽  
Organic Molecules ◽  
Coordination Complexes ◽  
Carbonic Anhydrases ◽  
Potential Applications ◽  
Kinetics Of Formation ◽  
Metallic Cations ◽  
General Aspects ◽  
Kinetics Of

GENERAL ASPECTS OF THE CHEMISTRY OF DITHIOCARBAMATES, THEIR METALLIC COMPLEXES AND THEIR INTERACTIONS WITH IMPORTANTE ENZYMES – A BRIEF REVISION. Dithiocarbamates (DTCs) comprise a series of compounds included in the class of 1,1`dithiolates. The application of these organic molecules in the coordination chemistry of some metals is well explored in the last decades, along with their potential applications in medicinal chemistry. In view of our expertise in this field, the syntheses of new DTCS, their coordination chemistry towards various metallic cations and their biocide activities, we summarize in this manuscript the outcomes of some investigations registered in the literature, involving the interactions of DTCs or their complexes with some key enzymes such as carbonic anhydrases, superoxide dismutase, urease, tyrosinase, glutathione, caspases and dehydrogenases. It is provided with a brief introduction of the chemistry of DTCs, electrochemistry, the kinetics of formation, solubility and stability towards solvation. The next topics summarize the results of some experiments concerning the inhibition of these cited enzymes effected by DTCs and some of their coordination complexes. The final remarks and conclusion of the outcomes are provided at the end of the manuscript.

Beryllium-chrome-azurol-S complexes

1968 ◽  
Vol 21 (3) ◽  
pp. 603 ◽  
Author(s):  
WG Baldwin ◽  
DR Stranks
Keyword(s):  
Ionic Strength ◽  
Complex Formation ◽  
Ion Exchange ◽  
Stability Constant ◽  
Anionic Complex ◽  
Acidity Constants ◽  
Chrome Azurol S ◽  
Major Species ◽  
The Stability ◽  
Ph Range

Complex formation between the aquated beryllium cation and the tetrabasic dyestuff chrome-azurol-S (H4CAS) has been studied by spectrophotometric, potentiometric, electrophoretic, and ion-exchange techniques. At least two complexes are shown to exist within the pH range 3-6. The major species is the anionic complex BeHCAS- for which log β11, = 4.66 � 0.08 at 25� and at ionic strength 0.lM (NaClO4) Coordination of beryllium is considered to occur at the quinonoid-,). carboxylato site in the HCAS8- ligand. The stability constant for the dinuclear species Be2CASO is shown to be log β21 = 15.8 � 0.1 under the same medium conditions. The dinuclear complex interferes with spectrophotometric measurements at beryllium concentrations exceeding 2.5 x 10-4. The acidity constants of H4CAS were determined at 25� and at an ionic strength 0.IM (NaClO,) as pK2a = 2.25 � 0.10,pK3a, = 4.88 � 0.05, pK4, = 11.75 � 0.05, whilst pK1a = -1.2 � 0.4.

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