A thermodynamic study of complexation of 18-crown-6 with Zn2+, Tl+, Hg2+ and $$ {\text{UO}}^{{{\text{2 + }}}}_{{\text{2}}} $$ cations in acetonitrile-dimethylformamide binary media and study the effect of anion on the stability constant of (18C6-Na+) complex in methanol solutions

Rounaghi, Gholam Hossein; Zavvar, Mohammad Hossein Arbab; Badiee, K.; Boosaidi, F.; Kazemi, Malihe Samadi

doi:10.1007/s10847-007-9338-8

Cited by 24 publications

(5 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The ability of the solvent molecules to compete with the donor atoms of the ligand towards the coordination sites of the cation and also the solvation of the ligand and the resulting complex are another factors that can thermodynamically influence the complexation process between such macrocyclic ligands and the metal cations [4,5].…”

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

View full text Add to dashboard Cite

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.

show abstract

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

View full text Add to dashboard Cite

show abstract

“…A non-monotonic behavior has also been observed for thermodynamic functions of several macrocyclic compound-metal ion complex formations in some binary mixed solvents [20]. This behavior may be due to strong interactions between the constituent solvent molecules which result in changes in some of the chemical and physical properties of each of the solvents, and therefore, changing their solvating ability towards the dissolved species.…”

Section: Discussionmentioning

confidence: 96%

Thermodynamic Study of the Complexation of p-Isopropylcalix[6]arene with Cs+ Cation in Dimethylsulfoxide-Acetonitrile Binary Media

et al. 2011

View full text Add to dashboard Cite

The complexation reactions between the macrocyclic ionophore, p-isopropylcalix[6]arene and Cs+ cation were studied in dimethylsulfoxide–acetonitrile (DMSO-AN) binary non-aqueous solvents at different temperatures using a conductometry method. The conductance data show that the stoichiometry of the (p-isopropylcalix[6]-arene·Cs)+ complex in all binary mixed solvents is 1:1. The stability of the complexes is affected by the composition of the binary solvent media and a non-linear behavior was observed for changes of log Kf of the complex versus the composition of the binary mixed solvents. The thermodynamic parameters (ΔH°c and ΔS°c) for formation of (p-isopropyl-calix[6]arene·Cs)+ complex were obtained from temperature dependence of the stability constant and the obtained results show that the (p-isopropylcalix[6]arene·Cs)+ complex is enthalpy destabilized, but entropy stabilized, and the values of the mentioned parameters are affected strongly by the nature and composition of the binary mixed solvents.

show abstract

“…This is a complicated problem because of an exceptionally great variety and specificity of chemical reactions in solutions. Recently, we have investigated the complexation processes of some of the crown ethers with various metal cations in pure and binary mixed organic solvents [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Complexation study of dibenzo-18-crown-6 with UO2 2+ cation in binary mixed non-aqueous solutions

Razghandi

Rounaghi

Kakhki

2011

J Incl Phenom Macrocycl Chem

View full text Add to dashboard Cite

The complexation reaction of macrocyclic ligand, dibenzo-18-crown-6 (DB18C6) with UO 2 2? cation was studied in ethylacetate-1,2-dichloroethane (EtOAc/ DCE), acetonitrile-1,2-dichloroethane (AN/DCE), methanol-1,2-dichloroethane (MeOH/DCE) and ethanol-1,2-dichloroethane (EtOH/DCE) binary solutions at different temperatures using the conductometric method. The conductance data show that the stoichiometry of the complex formed between DB18C6 and UO 2 2? cation is affected by the nature of the solvent systems. A non-linear behaviour was observed for changes of log K f of (DB18C6.UO 2 ) ?2 complex versus the composition of the binary mixed solvents. The values of thermodynamic quantities (DS°c, DH°c) for formation of (DB18C6.UO 2 ) ?2 complex were obtained from temperature dependence of the stability constant using the van't Hoff plots. The results show that in most cases, the complex is enthalpy stabilized and in all cases entropy stabilized and both parameters are affected by the nature and composition of the mixed solvents. In addition, the complex formation between dicyclohexyl-18-crown-6 (DCH18C6) and UO 2 2? cation was studied in pure AN and the results were compared with those of the (DB18C6.UO 2 ) ?2 complex.

show abstract

A thermodynamic study of complexation of 18-crown-6 with Zn2+, Tl+, Hg2+ and $$ {\text{UO}}^{{{\text{2 + }}}}_{{\text{2}}} $$ cations in acetonitrile-dimethylformamide binary media and study the effect of anion on the stability constant of (18C6-Na+) complex in methanol solutions

Cited by 24 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

Thermodynamic Study of the Complexation of p-Isopropylcalix[6]arene with Cs+ Cation in Dimethylsulfoxide-Acetonitrile Binary Media

Complexation study of dibenzo-18-crown-6 with UO2 2+ cation in binary mixed non-aqueous solutions

Contact Info

Product

Resources

About