Aminopolycarboxylates of rare earths. X. 1H-NMR spectroscopic study of the mechanism of dissociation of ethylenediamine-N,N,N′,N′-tetraacetate complexes of cerium(III) and yttrium(III)

G. Laurenczy, L. Radics, E. Brücher

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10 Citations (Scopus)

Abstract

The 1H-NMR signal of the carboxy methylene protons in Ceedta- or Yedta- is AB multiplet. On formation of the protonated complexes in solutions with lower pH, the multiplet signals are broadened. By means of line-shape analysis, the pH-dependence of the average lifetime (τ) before exchange of the carboxy methylene protons HA and HB was determined (at various temperatures in the case of Ceedta-). The dependence of the rate of the AB exchange process (1/τ) on the H+ ion concentration can be described by a similar relation as for the rate of the proton-catalyzed dissociation of the complexes. On the basis of the rate constants it is assumed that the proton-catalyzed AB exchange process of the carboxy methylene protons in Ceedta- and Yedta- occurs via formation of the same intermediates as in the proton-catalyzed dissociation of Ceedta- and Yedta-. The rate-determining step is also the same in the AB exchange and in the dissociation of the complexes; this is probably the formation of an intermediate containing one free protonated iminodiacetate group.

Original languageEnglish
Pages (from-to)219-223
Number of pages5
JournalInorganica Chimica Acta
Volume75
Issue numberC
DOIs
Publication statusPublished - 1983

Fingerprint

ethylenediamine
Cerium
Yttrium
cerium
yttrium
Rare earths
Protons
rare earth elements
Nuclear magnetic resonance
dissociation
nuclear magnetic resonance
protons
Ion exchange
methylene
fine structure
ion concentration
line shape
Proton Magnetic Resonance Spectroscopy
Rate constants

ASJC Scopus subject areas

  • Biochemistry
  • Inorganic Chemistry
  • Physical and Theoretical Chemistry
  • Materials Chemistry

Cite this

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title = "Aminopolycarboxylates of rare earths. X. 1H-NMR spectroscopic study of the mechanism of dissociation of ethylenediamine-N,N,N′,N′-tetraacetate complexes of cerium(III) and yttrium(III)",
abstract = "The 1H-NMR signal of the carboxy methylene protons in Ceedta- or Yedta- is AB multiplet. On formation of the protonated complexes in solutions with lower pH, the multiplet signals are broadened. By means of line-shape analysis, the pH-dependence of the average lifetime (τ) before exchange of the carboxy methylene protons HA and HB was determined (at various temperatures in the case of Ceedta-). The dependence of the rate of the AB exchange process (1/τ) on the H+ ion concentration can be described by a similar relation as for the rate of the proton-catalyzed dissociation of the complexes. On the basis of the rate constants it is assumed that the proton-catalyzed AB exchange process of the carboxy methylene protons in Ceedta- and Yedta- occurs via formation of the same intermediates as in the proton-catalyzed dissociation of Ceedta- and Yedta-. The rate-determining step is also the same in the AB exchange and in the dissociation of the complexes; this is probably the formation of an intermediate containing one free protonated iminodiacetate group.",
author = "G. Laurenczy and L. Radics and E. Br{\"u}cher",
year = "1983",
doi = "10.1016/S0020-1693(00)91216-7",
language = "English",
volume = "75",
pages = "219--223",
journal = "Inorganica Chimica Acta",
issn = "0020-1693",
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T1 - Aminopolycarboxylates of rare earths. X. 1H-NMR spectroscopic study of the mechanism of dissociation of ethylenediamine-N,N,N′,N′-tetraacetate complexes of cerium(III) and yttrium(III)

AU - Laurenczy, G.

AU - Radics, L.

AU - Brücher, E.

PY - 1983

Y1 - 1983

N2 - The 1H-NMR signal of the carboxy methylene protons in Ceedta- or Yedta- is AB multiplet. On formation of the protonated complexes in solutions with lower pH, the multiplet signals are broadened. By means of line-shape analysis, the pH-dependence of the average lifetime (τ) before exchange of the carboxy methylene protons HA and HB was determined (at various temperatures in the case of Ceedta-). The dependence of the rate of the AB exchange process (1/τ) on the H+ ion concentration can be described by a similar relation as for the rate of the proton-catalyzed dissociation of the complexes. On the basis of the rate constants it is assumed that the proton-catalyzed AB exchange process of the carboxy methylene protons in Ceedta- and Yedta- occurs via formation of the same intermediates as in the proton-catalyzed dissociation of Ceedta- and Yedta-. The rate-determining step is also the same in the AB exchange and in the dissociation of the complexes; this is probably the formation of an intermediate containing one free protonated iminodiacetate group.

AB - The 1H-NMR signal of the carboxy methylene protons in Ceedta- or Yedta- is AB multiplet. On formation of the protonated complexes in solutions with lower pH, the multiplet signals are broadened. By means of line-shape analysis, the pH-dependence of the average lifetime (τ) before exchange of the carboxy methylene protons HA and HB was determined (at various temperatures in the case of Ceedta-). The dependence of the rate of the AB exchange process (1/τ) on the H+ ion concentration can be described by a similar relation as for the rate of the proton-catalyzed dissociation of the complexes. On the basis of the rate constants it is assumed that the proton-catalyzed AB exchange process of the carboxy methylene protons in Ceedta- and Yedta- occurs via formation of the same intermediates as in the proton-catalyzed dissociation of Ceedta- and Yedta-. The rate-determining step is also the same in the AB exchange and in the dissociation of the complexes; this is probably the formation of an intermediate containing one free protonated iminodiacetate group.

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