•  English
    • Persian
    • English
  •   Login
  • Ferdowsi University of Mashhad
  • |
  • Information Center and Central Library
    • Persian
    • English
  • Home
  • Source Types
    • Journal Paper
    • Ebook
    • Conference Paper
    • Standard
    • Protocol
    • Thesis
  • Use Help
View Item 
  •   FUM Digital Library
  • Fum
  • Articles
  • ProfDoc
  • View Item
  •   FUM Digital Library
  • Fum
  • Articles
  • ProfDoc
  • View Item
  • All Fields
  • Title
  • Author
  • Year
  • Publisher
  • Subject
  • Publication Title
  • ISSN
  • DOI
  • ISBN
Advanced Search
JavaScript is disabled for your browser. Some features of this site may not work without it.

Electrical Conductance study of interactions of Cu2+ , Co2+ and Ni2+ metal cations with kryptofix-21 in acetonitrile - ethanol binary solvent solution

Author:
بنفشه صفاتی
,
غلامحسین رونقی
,
M. Ebrahimi
,
banafsheh sefaty
,
Glamhossein Ronagi
Year
: 2013
Abstract: The main characteristic of a crown ether is the complexation of the ether oxygens with various ionic species. The factors which influence the stability of the

metal cation -crown ether complexes include: the relative size of the cation and the cavity of the crown ether, the number of oxygen atoms in the ring, the

coplanarity of the oxygen atoms ,the symmetrical placement of the oxygen atoms, the basicity of the oxygen atoms, steric hindrance in the polyether ring ,the

nature of the cation and electrical charge on the cation [2,3] .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].The complexation reactions between Co 2+, Cu2+, Ni2+ metal cations with

the macrocyclic ligand , kryptofix -21,in pure acetonitrile , ethanol and also in acetonitrile- ethanol (AN-EtOH) binary mixtures have been studied at

different temperatures using conductometric method. the conductance data show that the stoichiometry of the complexes in most cases is 1:1 [ML]. But in the

case of Cu2+ cation a 1:2 [ML2] complex is formed in pure EtOH , which shows that stoichiometry of the complexes may be changed by the nature of the

medium. The stability constants of the 1:1[M: L] complexes were determined using a computer program, GENPLOT. The stability order of complexes

between kryptofix -21 and Co2+, Ni2+, Cu2+ cations at 250C in the binary solvent solution of AN- EtOH (mol % AN 0) is : ( kryptofix-21. Ni ) 2+ > (kryptofix-

21. Cu) 2+ > ( kryptofix-21. Co ) 2+, but in case of another AN- EtOH binary solvent solution (mol % AN 25) it was found to be : (kryptofix-21. Cu ) 2+>

(kryptofix-21. Co) 2+> ( kryptofix-21. Ni) 2+ and in case of AN- EtOH binary mixed systems (mol % AN 50 and 75) the stability order changes as : ( kryptofix

- 21. Co) 2+> ( kryptofix-21. Cu) 2+> ( kryptofix-21. Ni) 2+ The order of the stability of the complexes in pure AN is (kryptofix - 21. Co) 2+> (kryptofix-21. Ni)

2+.> (kryptofix-21. Cu) 2+ .The values of stability constants of complexes ,which were obtained from conductometric data , show that the stability of

complexes is affected by the nature and composition of the binary mixed solvents and a non-linear behavior was observed for variation logKf of the

complexes versus the composition of the solvent system .The values of thermodynamic parameters (ΔHc

0, ΔSc

0 ) for formation of complexes show that in

most solution systems , the complexes are enthalpy destabilize but entropy stabilized.
URI: http://libsearch.um.ac.ir:80/fum/handle/fum/3384827
Keyword(s): kryptofix-21,acetonitrile - ethanol binary solvent
Collections :
  • ProfDoc
  • Show Full MetaData Hide Full MetaData
  • Statistics

    Electrical Conductance study of interactions of Cu2+ , Co2+ and Ni2+ metal cations with kryptofix-21 in acetonitrile - ethanol binary solvent solution

Show full item record

contributor authorبنفشه صفاتیen
contributor authorغلامحسین رونقیen
contributor authorM. Ebrahimien
contributor authorbanafsheh sefatyfa
contributor authorGlamhossein Ronagifa
date accessioned2020-06-06T14:09:29Z
date available2020-06-06T14:09:29Z
date copyright2/26/2013
date issued2013
identifier urihttp://libsearch.um.ac.ir:80/fum/handle/fum/3384827
description abstractThe main characteristic of a crown ether is the complexation of the ether oxygens with various ionic species. The factors which influence the stability of the

metal cation -crown ether complexes include: the relative size of the cation and the cavity of the crown ether, the number of oxygen atoms in the ring, the

coplanarity of the oxygen atoms ,the symmetrical placement of the oxygen atoms, the basicity of the oxygen atoms, steric hindrance in the polyether ring ,the

nature of the cation and electrical charge on the cation [2,3] .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].The complexation reactions between Co 2+, Cu2+, Ni2+ metal cations with

the macrocyclic ligand , kryptofix -21,in pure acetonitrile , ethanol and also in acetonitrile- ethanol (AN-EtOH) binary mixtures have been studied at

different temperatures using conductometric method. the conductance data show that the stoichiometry of the complexes in most cases is 1:1 [ML]. But in the

case of Cu2+ cation a 1:2 [ML2] complex is formed in pure EtOH , which shows that stoichiometry of the complexes may be changed by the nature of the

medium. The stability constants of the 1:1[M: L] complexes were determined using a computer program, GENPLOT. The stability order of complexes

between kryptofix -21 and Co2+, Ni2+, Cu2+ cations at 250C in the binary solvent solution of AN- EtOH (mol % AN 0) is : ( kryptofix-21. Ni ) 2+ > (kryptofix-

21. Cu) 2+ > ( kryptofix-21. Co ) 2+, but in case of another AN- EtOH binary solvent solution (mol % AN 25) it was found to be : (kryptofix-21. Cu ) 2+>

(kryptofix-21. Co) 2+> ( kryptofix-21. Ni) 2+ and in case of AN- EtOH binary mixed systems (mol % AN 50 and 75) the stability order changes as : ( kryptofix

- 21. Co) 2+> ( kryptofix-21. Cu) 2+> ( kryptofix-21. Ni) 2+ The order of the stability of the complexes in pure AN is (kryptofix - 21. Co) 2+> (kryptofix-21. Ni)

2+.> (kryptofix-21. Cu) 2+ .The values of stability constants of complexes ,which were obtained from conductometric data , show that the stability of

complexes is affected by the nature and composition of the binary mixed solvents and a non-linear behavior was observed for variation logKf of the

complexes versus the composition of the solvent system .The values of thermodynamic parameters (ΔHc

0, ΔSc

0 ) for formation of complexes show that in

most solution systems , the complexes are enthalpy destabilize but entropy stabilized.
en
languageEnglish
titleElectrical Conductance study of interactions of Cu2+ , Co2+ and Ni2+ metal cations with kryptofix-21 in acetonitrile - ethanol binary solvent solutionen
typeConference Paper
contenttypeExternal Fulltext
subject keywordskryptofix-21en
subject keywordsacetonitrile - ethanol binary solventen
identifier linkhttps://profdoc.um.ac.ir/paper-abstract-1033660.html
conference titleنوزدهمین سمینار شیمی تجزیه ایرانfa
conference locationمشهدfa
identifier articleid1033660
  • About Us
نرم افزار کتابخانه دیجیتال "دی اسپیس" فارسی شده توسط یابش برای کتابخانه های ایرانی | تماس با یابش
DSpace software copyright © 2019-2022  DuraSpace