The Experts below are selected from a list of 114 Experts worldwide ranked by ideXlab platform
Angela Danil F De Namor - One of the best experts on this subject based on the ideXlab platform.
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thermodynamics of complexation of a lower rim calix 4 arene Ketone Derivative and the sodium cation in n n dimethylformamide acetonitrile mixtures
Journal of Physical Chemistry B, 2001Co-Authors: Angela Danil F De Namor, Dorota Kowalska, And Yizhak Marcus, Jose VillanuevasalasAbstract:Stability constants and derived standard Gibbs energies, enthalpies, and entropies of complexation of a lower rim calix(4)arene Ketone Derivative, namely 5,11,17,23-tetra p-tert-butyl-25,26,27,28-tetra(benzoyl)methoxycalix(4)arene and the sodium cation in N, N-dimethylformamide/acetonitrile mixtures at 298.15 K are first reported. Stability constants were determined potentiometrically by the use of a sodium selective electrode with the silver/silver (I) reference electrode. A linear relationship is found between the stability constant and the solvent composition. The strength of complexation decreases from acetonitrile through the mixtures. The minimum stability for this system was found in N, N-dimethylformamide. The striking feature of these data are the small variations in enthalpy observed in the solvent mixtures relative to their pure solvents. In all cases, the complexation process in these solvent mixtures is enthalpically controlled. However, the higher stability found by increasing the content of...
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Thermodynamics of Complexation of a Lower Rim Calix(4)arene Ketone Derivative and the Sodium Cation in N, N-Dimethylformamide/Acetonitrile Mixtures.
Journal of Physical Chemistry B, 2001Co-Authors: Angela Danil F De Namor, Dorota Kowalska, And Yizhak Marcus, Jose Villanueva-salasAbstract:Stability constants and derived standard Gibbs energies, enthalpies, and entropies of complexation of a lower rim calix(4)arene Ketone Derivative, namely 5,11,17,23-tetra p-tert-butyl-25,26,27,28-tetra(benzoyl)methoxycalix(4)arene and the sodium cation in N, N-dimethylformamide/acetonitrile mixtures at 298.15 K are first reported. Stability constants were determined potentiometrically by the use of a sodium selective electrode with the silver/silver (I) reference electrode. A linear relationship is found between the stability constant and the solvent composition. The strength of complexation decreases from acetonitrile through the mixtures. The minimum stability for this system was found in N, N-dimethylformamide. The striking feature of these data are the small variations in enthalpy observed in the solvent mixtures relative to their pure solvents. In all cases, the complexation process in these solvent mixtures is enthalpically controlled. However, the higher stability found by increasing the content of...
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lower rim calix 4 arene Ketone Derivatives and their interaction with alkali metal cations structural and thermodynamic solution and complexation characterisation of the tetraphenyl Ketone Derivative and its sodium complex
Physical Chemistry Chemical Physics, 2001Co-Authors: Angela Danil F De Namor, Dorota Kowalska, Eduardo E Castellano, Oscar E Piro, Felix Sueros J Velarde, Jose Villanueva SalasAbstract:A modified method for the synthesis of 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetra(benzoyl)methoxycalix(4)arene (1) and 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetra(acetoyl)methoxycalix(4)arene (2) using 18-crown-6 as phase transfer catalyst is reported. Ligand 1 was structurally (1H NMR and X-ray crystallography) and thermodynamically characterised. An account of the steps required for the formulation of an equation representative of the complexation process involving metal cations and macrocycles is given using as an illustrative example the interaction of 1 with the Na(I) cation. Thus, detailed thermodynamics of this system are first reported taking into account the solution properties of the reactants and the product in various solvents with the aim of assessing quantitatively the medium effect on the complexation process. The sodium:monoacetonitrile:1 complex was isolated and its molecular structure was determinated from X-ray diffraction data. The calix now adopts a more symmetric cone conformation than the free ligand and its hydrophobic cavity is filled with an acetonitrile solvent molecule. The hydrophilic pocket hosts the sodium cation which is in an eight-fold coordination with the four ethereal oxygen atoms [average d(Na–O) = 2.45(4) A] and the four carbonyl oxygen atoms [average d(Na–O) = 2.51(4) A] forming the corners of a distorted Archimedean square antiprism. The key structural features relevant to the complexation process are discussed. 1H NMR and conductance measurements have been used to assess the interaction of 1 and 2 with alkali metal cations. Final conclusions are given. Attention is drawn about the relevance of detailed thermodynamic studies on cation complexation processes involving calixarene Derivatives. This is discussed within the context of selectivity and the factors controlling it in solution processes.
Jose Villanuevasalas - One of the best experts on this subject based on the ideXlab platform.
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thermodynamics of complexation of a lower rim calix 4 arene Ketone Derivative and the sodium cation in n n dimethylformamide acetonitrile mixtures
Journal of Physical Chemistry B, 2001Co-Authors: Angela Danil F De Namor, Dorota Kowalska, And Yizhak Marcus, Jose VillanuevasalasAbstract:Stability constants and derived standard Gibbs energies, enthalpies, and entropies of complexation of a lower rim calix(4)arene Ketone Derivative, namely 5,11,17,23-tetra p-tert-butyl-25,26,27,28-tetra(benzoyl)methoxycalix(4)arene and the sodium cation in N, N-dimethylformamide/acetonitrile mixtures at 298.15 K are first reported. Stability constants were determined potentiometrically by the use of a sodium selective electrode with the silver/silver (I) reference electrode. A linear relationship is found between the stability constant and the solvent composition. The strength of complexation decreases from acetonitrile through the mixtures. The minimum stability for this system was found in N, N-dimethylformamide. The striking feature of these data are the small variations in enthalpy observed in the solvent mixtures relative to their pure solvents. In all cases, the complexation process in these solvent mixtures is enthalpically controlled. However, the higher stability found by increasing the content of...
Dorota Kowalska - One of the best experts on this subject based on the ideXlab platform.
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thermodynamics of complexation of a lower rim calix 4 arene Ketone Derivative and the sodium cation in n n dimethylformamide acetonitrile mixtures
Journal of Physical Chemistry B, 2001Co-Authors: Angela Danil F De Namor, Dorota Kowalska, And Yizhak Marcus, Jose VillanuevasalasAbstract:Stability constants and derived standard Gibbs energies, enthalpies, and entropies of complexation of a lower rim calix(4)arene Ketone Derivative, namely 5,11,17,23-tetra p-tert-butyl-25,26,27,28-tetra(benzoyl)methoxycalix(4)arene and the sodium cation in N, N-dimethylformamide/acetonitrile mixtures at 298.15 K are first reported. Stability constants were determined potentiometrically by the use of a sodium selective electrode with the silver/silver (I) reference electrode. A linear relationship is found between the stability constant and the solvent composition. The strength of complexation decreases from acetonitrile through the mixtures. The minimum stability for this system was found in N, N-dimethylformamide. The striking feature of these data are the small variations in enthalpy observed in the solvent mixtures relative to their pure solvents. In all cases, the complexation process in these solvent mixtures is enthalpically controlled. However, the higher stability found by increasing the content of...
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Thermodynamics of Complexation of a Lower Rim Calix(4)arene Ketone Derivative and the Sodium Cation in N, N-Dimethylformamide/Acetonitrile Mixtures.
Journal of Physical Chemistry B, 2001Co-Authors: Angela Danil F De Namor, Dorota Kowalska, And Yizhak Marcus, Jose Villanueva-salasAbstract:Stability constants and derived standard Gibbs energies, enthalpies, and entropies of complexation of a lower rim calix(4)arene Ketone Derivative, namely 5,11,17,23-tetra p-tert-butyl-25,26,27,28-tetra(benzoyl)methoxycalix(4)arene and the sodium cation in N, N-dimethylformamide/acetonitrile mixtures at 298.15 K are first reported. Stability constants were determined potentiometrically by the use of a sodium selective electrode with the silver/silver (I) reference electrode. A linear relationship is found between the stability constant and the solvent composition. The strength of complexation decreases from acetonitrile through the mixtures. The minimum stability for this system was found in N, N-dimethylformamide. The striking feature of these data are the small variations in enthalpy observed in the solvent mixtures relative to their pure solvents. In all cases, the complexation process in these solvent mixtures is enthalpically controlled. However, the higher stability found by increasing the content of...
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lower rim calix 4 arene Ketone Derivatives and their interaction with alkali metal cations structural and thermodynamic solution and complexation characterisation of the tetraphenyl Ketone Derivative and its sodium complex
Physical Chemistry Chemical Physics, 2001Co-Authors: Angela Danil F De Namor, Dorota Kowalska, Eduardo E Castellano, Oscar E Piro, Felix Sueros J Velarde, Jose Villanueva SalasAbstract:A modified method for the synthesis of 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetra(benzoyl)methoxycalix(4)arene (1) and 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetra(acetoyl)methoxycalix(4)arene (2) using 18-crown-6 as phase transfer catalyst is reported. Ligand 1 was structurally (1H NMR and X-ray crystallography) and thermodynamically characterised. An account of the steps required for the formulation of an equation representative of the complexation process involving metal cations and macrocycles is given using as an illustrative example the interaction of 1 with the Na(I) cation. Thus, detailed thermodynamics of this system are first reported taking into account the solution properties of the reactants and the product in various solvents with the aim of assessing quantitatively the medium effect on the complexation process. The sodium:monoacetonitrile:1 complex was isolated and its molecular structure was determinated from X-ray diffraction data. The calix now adopts a more symmetric cone conformation than the free ligand and its hydrophobic cavity is filled with an acetonitrile solvent molecule. The hydrophilic pocket hosts the sodium cation which is in an eight-fold coordination with the four ethereal oxygen atoms [average d(Na–O) = 2.45(4) A] and the four carbonyl oxygen atoms [average d(Na–O) = 2.51(4) A] forming the corners of a distorted Archimedean square antiprism. The key structural features relevant to the complexation process are discussed. 1H NMR and conductance measurements have been used to assess the interaction of 1 and 2 with alkali metal cations. Final conclusions are given. Attention is drawn about the relevance of detailed thermodynamic studies on cation complexation processes involving calixarene Derivatives. This is discussed within the context of selectivity and the factors controlling it in solution processes.
Vladislav Tomisic - One of the best experts on this subject based on the ideXlab platform.
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solvation effect on complexation of alkali metal cations by a calix 4 arene Ketone Derivative
Journal of Physical Chemistry B, 2017Co-Authors: Josip Požar, Ivana Niksicfranjic, Marija Cvetnic, Katarina Leko, Nikola Cindro, Katarina Piculjan, Ivana Borilovic, Leo Frkanec, Vladislav TomisicAbstract:The medium effect on the complexation of alkali metal cations with a calix[4]arene Ketone Derivative (L) was systematically examined in methanol, ethanol, N-methylformamide, N,N-dimethylformamide, dimethyl sulfoxide, and acetonitrile. In all solvents the binding of Na+ cation by L was rather efficient, whereas the complexation of other alkali metal cations was observed only in methanol and acetonitrile. Complexation reactions were enthalpically controlled, while ligand dissolution was endothermic in all cases. A notable influence of the solvent on NaL+ complex stability could be mainly attributed to the differences in complexation entropies. The higher NaL+ stability in comparison to complexes with other alkali metal cations in acetonitrile was predominantly due to a more favorable complexation enthalpy. The 1H NMR investigations revealed a relatively low affinity of the calixarene sodium complex for inclusion of the solvent molecule in the calixarene hydrophobic cavity, with the exception of acetonitrile...
And Yizhak Marcus - One of the best experts on this subject based on the ideXlab platform.
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thermodynamics of complexation of a lower rim calix 4 arene Ketone Derivative and the sodium cation in n n dimethylformamide acetonitrile mixtures
Journal of Physical Chemistry B, 2001Co-Authors: Angela Danil F De Namor, Dorota Kowalska, And Yizhak Marcus, Jose VillanuevasalasAbstract:Stability constants and derived standard Gibbs energies, enthalpies, and entropies of complexation of a lower rim calix(4)arene Ketone Derivative, namely 5,11,17,23-tetra p-tert-butyl-25,26,27,28-tetra(benzoyl)methoxycalix(4)arene and the sodium cation in N, N-dimethylformamide/acetonitrile mixtures at 298.15 K are first reported. Stability constants were determined potentiometrically by the use of a sodium selective electrode with the silver/silver (I) reference electrode. A linear relationship is found between the stability constant and the solvent composition. The strength of complexation decreases from acetonitrile through the mixtures. The minimum stability for this system was found in N, N-dimethylformamide. The striking feature of these data are the small variations in enthalpy observed in the solvent mixtures relative to their pure solvents. In all cases, the complexation process in these solvent mixtures is enthalpically controlled. However, the higher stability found by increasing the content of...
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Thermodynamics of Complexation of a Lower Rim Calix(4)arene Ketone Derivative and the Sodium Cation in N, N-Dimethylformamide/Acetonitrile Mixtures.
Journal of Physical Chemistry B, 2001Co-Authors: Angela Danil F De Namor, Dorota Kowalska, And Yizhak Marcus, Jose Villanueva-salasAbstract:Stability constants and derived standard Gibbs energies, enthalpies, and entropies of complexation of a lower rim calix(4)arene Ketone Derivative, namely 5,11,17,23-tetra p-tert-butyl-25,26,27,28-tetra(benzoyl)methoxycalix(4)arene and the sodium cation in N, N-dimethylformamide/acetonitrile mixtures at 298.15 K are first reported. Stability constants were determined potentiometrically by the use of a sodium selective electrode with the silver/silver (I) reference electrode. A linear relationship is found between the stability constant and the solvent composition. The strength of complexation decreases from acetonitrile through the mixtures. The minimum stability for this system was found in N, N-dimethylformamide. The striking feature of these data are the small variations in enthalpy observed in the solvent mixtures relative to their pure solvents. In all cases, the complexation process in these solvent mixtures is enthalpically controlled. However, the higher stability found by increasing the content of...
