Thermodynamics of cesium complexes formation with 18-crown-6 in ionic liquids

  • A. G. Vendilo
  • H. Rönkkömäki
  • M. Hannu-Kuure
  • M. Lajunen
  • J. Asikkala
  • V. G. Krasovsky
  • E. A. Chernikova
  • P. Oksman
  • L. H. J. Lajunen
  • T. Tuomi
  • K. I. Popov
Original Article


Thermodynamic data for cesium complexes formation with 18-crown-6 (18C6, L) [Cs(18C6)]+ in N-butyl-4-methyl-pyridinium tetrafluoroborate ([BMPy][BF4], I), in 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4], II) and in 1-butyl-3-methylimidazolium dicyanamide ([BMIM][N(CN)2], III) were measured with NMR 133Cs technique at 23–50 °C. The stability of cesium complex in RTILs is estimated to be in the range between water and DMFA. Stability constants for [Cs(18C6)]+ are found to decrease as temperature is increasing. The following values for lgK(Cs+L) and ΔH(Cs+L) at 23 °C are determined: 2.6 (0.3), −47(1) kJ/mol (RTIL I); 2.8(0.3), −80(3) kJ/mol (RTIL II) and 3.03 (0.08), −47(2) kJ/mol (RTIL III). It is demonstrated that enthalpy change promotes complex formation while the corresponding change of entropy is negative and provides decomposition of [Cs(18C6)]+.


RTIL Stability constants Complexes Cesium 18-crown-6 133Cs NMR 



The authors would like to thank the Russian Foundation for Basic Research (Grant 07-08-00246) and the Academy of Science of Finland for their financial support of the work. We also wish to express our gratitude to Päivi Joensuu for assistance in sample analysis.


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Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  • A. G. Vendilo
    • 1
  • H. Rönkkömäki
    • 2
  • M. Hannu-Kuure
    • 3
  • M. Lajunen
    • 3
  • J. Asikkala
    • 3
  • V. G. Krasovsky
    • 4
  • E. A. Chernikova
    • 4
  • P. Oksman
    • 3
  • L. H. J. Lajunen
    • 3
  • T. Tuomi
    • 5
  • K. I. Popov
    • 6
  1. 1.State Research Institute of Reagents and High Purity Substances (IREA)MoscowRussia
  2. 2.Finnish Institute of Occupational HealthOuluFinland
  3. 3.Department of ChemistryUniversity of OuluOuluFinland
  4. 4.Zelinsky Institute of Organic Chemistry RASMoscowRussia
  5. 5.Finnish Institute of Occupational HealthHelsinkiFinland
  6. 6.Department of Physical and Colloid ChemistryMoscow State University of Food TechnologiesMoscowRussia

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