Intermolecular dynamics and paramagnetic properties of ethylenediaminetetraacetate complexes with the yttrium subgroup rare earth elements using nuclear magnetic resonance

Sergey P. Babailov

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8 Citations (Scopus)

Abstract

1H nuclear magnetic resonance (NMR) measurements are reported for the D 2O solutions of [Ln 3+(EDTA 4-)] - complexes, where EDTA 4- is ethylenediaminetetraacetate anion, Ln 3+ = Tb 3+ (I), Ho 3+ (II), Tm 3+ (III), Yb 3+ (IV) and Lu 3+ (V). Temperature dependencies of the 1H NMR spectra of paramagnetic I-IV have been analyzed using the dynamic NMR methods. It is found that the activation free energies (ΔG 298) of the intermolecular EDTA ions exchange at [Ln 3+(EDTA 4-)] - complexes are 60±3 (I), 66±3 (II), 69±3 (III) and 74±3 (IV) kJ/mol (at pD = 7). A monotonic increase of the free energy of chemical exchange processes along the series of lanthanide [Ln 3+ (EDTA 4-)] - complexes is probably related to the lanthanide contraction. The obtained results indicate that coordination compounds I-IV may be considered as thermometric NMR sensors and lanthanide paramagnetic probes for in situ temperature control in solution.

Original languageEnglish
Pages (from-to)793-797
Number of pages5
JournalMagnetic Resonance in Chemistry
Volume50
Issue number12
DOIs
Publication statusPublished - Dec 2012
Externally publishedYes

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Keywords

  • aqueous solutions
  • dynamic NMR
  • EDTA
  • ethylenediaminetetraacetic acid
  • free energy of activation
  • kinetics of chemical exchange
  • lanthanide complexes
  • lanthanide-induced shifts in NMR spectra
  • molecular dynamics
  • two-site exchange

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)

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