Thermodynamic behavior of complexation process between dibenzo-18-crown-6 and K+, Ag+, NH 4 + , and Hg2+ cations in ethylacetate-dimethylformamide binary media

Rounaghi, Gholam Hossein; Zavar, Mohammad Hossein Arbab; Kakhki, Roya Mohammad Zadeh

doi:10.1134/s1070328408030020

Cited by 15 publications

(6 citation statements)

References 16 publications

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“…We are especially interested in study of the thermodynamics of complexation and selectivity profiles of crown compounds towards the various metal cations [22,23].…”

Section: Introductionmentioning

confidence: 99%

Conductometric study of complexation reaction between 15-crown-5 and Cr3+, Mn2+ and Zn2+ metal cations in pure and binary mixed organic solvents

Rounaghi

Mohajeri

Atashi

et al. 2011

J Incl Phenom Macrocycl Chem

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The stability constants (K f ) for the complexation reactions of Cr 3? , Mn 2? and Zn 2? metal cations with macrocyclic ligand, 15-crown-5 (15C5), in acetonitrile (AN), ethanol (EtOH) and also in their binary solutions (AN-EtOH) were determined at different temperatures, using conductometric method. 15C5 forms 1:1 complexes with Cr 3? , Mn 2? and Zn 2? cations in solutions. A nonlinear behaviour was observed for changes of logK f of the metal ion complexes versus the composition of the mixed solvent. The order of stability of the metal-ion complexes in pure AN and in a binary solution of AN-EtOH (mol% AN = 52) at 25°C was found to be: (15C5Zn) 2? [ (15C5ÁMn) 2? [ (15C5ÁCr) 3? , but in the case of pure EtOH at the same temperature, it changes to: (15C5ÁZn) 2? [ (15C5ÁCr) 3? [ (15C5ÁMn) 2? . The results also show that the stability sequence of the complexes in the other binary solutions of AN-EtOH (mol% AN = 26 and mol% AN = 76) varies in order: (15C5ÁCr) 3? * (15C5ÁZn) 2? [ (15C5ÁMn) 2? . The values of the standard thermodynamic quantities (DH C°, DS C°) for formation of (15C15-Cr 3? ), (15C5-Mn 2? ) and (15C5-Zn 2? ) complexes were obtained from the temperature dependence of the stability constants and the results show that the thermodynamics of complexation reactions is affected by nature and composition of the solvent systems and in most solution systems, the complexes are enthalpy stabilized but entropy destabilized.

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“…We are especially interested in study of the thermodynamics of complexation and selectivity profiles of crown compounds towards the various metal cations [22,23].…”

Section: Introductionmentioning

confidence: 99%

Conductometric study of complexation reaction between 15-crown-5 and Cr3+, Mn2+ and Zn2+ metal cations in pure and binary mixed organic solvents

Rounaghi

Mohajeri

Atashi

et al. 2011

J Incl Phenom Macrocycl Chem

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“…The attachment of phenyl groups to this ligand increases its lipophilicity, thus increasing its solubility and effectively trapping it in the organic phase into one or both of aqueous phases. In addition, the interaction of π-electron system presents in aromatic rings with the silver(I) cation may be effective on complexation process between this metal cation and the ligand [25,26]. Therefore, it seems that silver(I) cation gets self encapsulated by the ligand and hence shows maximum transport efficiency.…”

Section: Effect Of Carrier Concentration In the Membrane Phasementioning

confidence: 99%

Efficient and Selective Transport of Silver(I) Cation Across a Bulk Dichloromethane Membrane Using 1,13‐Bis(8‐quinolyl)‐1,4,7,10,13‐pentaoxatridecane as a Carrier

Rounaghi

Ghaemi

2012

Journal of Chemistry

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1,13-Bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane (Kryptofix 5) was used as a highly efficient carrier for the transport of silver(I) cation through a dichloromethane (DCM) bulk liquid membrane. In order to achieve the highest transport efficiency of Ag+cation across the bulk liquid membrane system, the influence of different parameters was studied. These include: the nature of various organic solvents as liquid membrane phase, concentration of the carrier in the membrane phase, concentration of picric acid as counter anion in the source phase, type of various stripping agents in the receiving phase, concentration of thiosulfate anion (S2O32-) as a suitable stripping agent, pH of the source and receiving phases, volume of the receiving phase and equilibrium time of transport which were optimized. In the optimum procedure conditions, the transport of a 3×10-4M solution of silver(I) cation was observed (88.03 ± 0.82%) after 4 hours. The selectivity of Ag+transport from aqueous solutions containing equimolar concentration of other metal cations such as Pb2+, Co2+, Zn2+, Cd2+, Cu2+and Fe2+was also investigated.

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“…These hosts have three dimensional structures and therefore, can form stable complex with various cations. The interactions between host and guest are via oxygen, nitrogen or sulfur heteroatoms in the skeleton of crown ether with cations [5][6][7][8][9][10][11]. Moreover, due to different hole size, they can form various types of complexes with high selectivity.…”

Section: Introductionmentioning

confidence: 99%

“…Also thermodynamic has a significant effect on the stability of complex. Therefore, thermodynamic parameters are of interest for scientific solvent selection in various applications [5][6][7][8][9]. Since little attention has been paid to rare earth complexation, hence, information about the coordination behavior of crown ethers towards these metal cations is relatively scarce.…”

Section: Introductionmentioning

confidence: 99%

A conductometric study on the effect of solvent upon complex formation between kryptofix22dd with Ho3+ metal cation in organic solvents

Kakhki¹

2019

Bull. Chem. Soc. Eth.

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The complexation reaction between Ho 3+ cation with macrocyclic ligand kryptofix22DD was studied in ethyl acetate (EtOAC), methanol (MeOH), propylene carbonate (PC), tetrahydrofuran (THF) at different temperatures by coductometric method. Kryptofix22DD forms a 1:1 complex with Ho + cation. The stability of (kryptofix22DD.Ho) 3+ complex changes with the type of the organic solvents and also with temperature. The stability constant of the complex in the non-aqueous solvents varies in order: EtOAC ≥ THF > PC ≥ MeOH. By plotting the van't Hoff diagrams, the values of standard thermodynamic parameters such as enthalpy (∆H°c), entropy (∆S°c) and Gibbs free energy (ΔG°C), for formation of (kryptofix22DD.Ho) 3+ complex were obtained. The results showed that the entropy and enthalpy of complexation reaction between kryptofix22DD with Ho 3+ metal cation depend on the nature of the solvents.

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Thermodynamic behavior of complexation process between dibenzo-18-crown-6 and K+, Ag+, NH 4 + , and Hg2+ cations in ethylacetate-dimethylformamide binary media

Cited by 15 publications

References 16 publications

Conductometric study of complexation reaction between 15-crown-5 and Cr3+, Mn2+ and Zn2+ metal cations in pure and binary mixed organic solvents

Conductometric study of complexation reaction between 15-crown-5 and Cr3+, Mn2+ and Zn2+ metal cations in pure and binary mixed organic solvents

Efficient and Selective Transport of Silver(I) Cation Across a Bulk Dichloromethane Membrane Using 1,13‐Bis(8‐quinolyl)‐1,4,7,10,13‐pentaoxatridecane as a Carrier

A conductometric study on the effect of solvent upon complex formation between kryptofix22dd with Ho3+ metal cation in organic solvents

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