Thermodynamic behavior of complexation process between benzo-15-crown-5 with Li+, Na+, K+, and NH4 + cations in acetonitrile–methanol binary media

Rounaghi, Gholam Hossein; Razavipanah, E.; Kaveh, Fahimeh

doi:10.1007/s10847-010-9780-x

Cited by 6 publications

(2 citation statements)

References 30 publications

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“…The extraction can be monitored by UV/Vis spectroscopy 7,8 and enables thermodynamic analysis if suitable counterions are used. [9][10][11][12][13] Besides, the thermodynamics of complex formation of ionic compounds with crown ethers in various organic solvents [14][15][16] as well as in mixed non-aqueous solutions 17,18 has been explored. The stability of a formed complex depends on the diameter of the crown ether and the radius of the metal cation.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic analysis of alkali metal complex formation of polymer-bonded crown ether

Bey

Dreyer

Abetz

2017

Phys. Chem. Chem. Phys.

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The complex formation of two crown ethers with colored alkali metal salts was investigated by UV/Vis spectroscopy. Complexation was accomplished with free benzo-15-crown-5 (B15C5) and 15-crown-5 bonded to a diblock copolymer (Poly15C5). The diblock copolymer was synthesized by two controlled polymerization techniques and copper(I)-catalyzed azide-alkyne cycloaddition. Depending on the inserted cation, 1 : 1-or 1 : 2-complexes are formed. A significant difference of the stability constants was determined by concentration dependence solvent extraction with sodium or potassium salt. For Poly15C5 the stability constants increase for both salts compared to the stability constants of B15C5, which suggests a more effective complexation. Evaluation of the thermodynamics (DH, DS, DG) of cation complexation was achieved by temperature dependence phase extraction on the basis of established thermodynamic equations. Remarkably, in all cases the entropic gain seems to be the major propulsion facilitating the complexation between alkali metal salts and crown ethers. Indeed, by using Poly15C5 a more pronounced dependency of enthalpy and entropy on the complex formation is calculated.

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Section: Introductionmentioning

confidence: 99%

Thermodynamic analysis of alkali metal complex formation of polymer-bonded crown ether

Bey

Dreyer

Abetz

2017

Phys. Chem. Chem. Phys.

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“…The study of complexation of various macrocyclic compounds with the metal cations in different solvents or solvent mix tures may indicate new approaches for developing pharmaceutical systems or a way to cross the blood organ barrier. In the past two decades, we have employed conductometry technique to investigate the thermodynamics of a number of metal ion macrocy cle complexes in different non aqueous and mixed solvents [17][18][19][20]. Conductometry offers a simple and an inexpensive experimental arrangement for such investigations.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic study of complex formation between Ni2+ and Co2+ cations and 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane (kryptofix 5) in binary mixed nonaqueous solutions

Zarifpour

Rounaghi

Tarahomi

2014

Russ. J. Phys. Chem.

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Conductometric titrations were performed in pure and binary solvent solutions of ethyl acetate (EtOAc), methyl acetate (MeOAc) and methanol (MeOH) with acetonitrile (AN) at 288, 298, 308, and 318 K to determine the stoichiometry, the complex stability constants and the standard thermodynamic parameters for the complexation of nickel(II) and cobalt(II) cations with 1,13 bis(8 quinolyl) 1,4,7,10,13 pentaoxatridecane (kryptofix 5). The stability constants of the resulting 1:1 complexes formed between the metal cations and the ligand in different solvent mixtures were determined by computer fitting of the conduc tance mole ratio data. The results revealed that the stability order of (kryptofix 5)-Ni 2+ and (kryptofix 5)-Co 2+ complexes changes with nature and composition of the solvent system. There is a non linear relationship between the logK f values of complexes and the mole fraction of acetonitrile in the mixed solvent system. In addition, the conductometric data show that the stoichiometry of the complexes formed between the nickel(II) and cobalt(II) cations with the acyclic ligand changes with the nature of the solvent. The enthalpy and entropy values for the 1 : 1 [ML] complexation reactions were evaluated from the temperature depen dence of the formation constants. Thermodynamically, in most of systems, the complexation processes of nickel(II) and cobalt(II) cations with kryptofix 5, are both enthalpy and entropy stabilized and the values of these parameters are influenced by the nature and composition of the binary mixed solvent solutions.

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Modified asynchronous orthogonal sample design scheme @ Job’s method to determine the stoichiometric ratio in the molecular association system

Zhang

2020

Journal of Molecular Structure

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Thermodynamic behavior of complexation process between benzo-15-crown-5 with Li+, Na+, K+, and NH4 + cations in acetonitrile–methanol binary media

Cited by 6 publications

References 30 publications

Thermodynamic analysis of alkali metal complex formation of polymer-bonded crown ether

Thermodynamic analysis of alkali metal complex formation of polymer-bonded crown ether

Thermodynamic study of complex formation between Ni2+ and Co2+ cations and 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane (kryptofix 5) in binary mixed nonaqueous solutions

Modified asynchronous orthogonal sample design scheme @ Job’s method to determine the stoichiometric ratio in the molecular association system

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