Ändra sökning
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Structure, equilibrium and ligand exchange dynamics in the binary and ternary dioxouranium(VI)-ethylenediamine-N,N '-diacetic acid-fluoride system: a potentiometric, NMR and X-ray crystallographic study
KTH, Skolan för kemivetenskap (CHE), Kemi, Oorganisk kemi.ORCID-id: 0000-0002-7552-1076
KTH, Skolan för kemivetenskap (CHE), Kemi, Oorganisk kemi.
2006 (Engelska)Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, nr 43, s. 5176-5183Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The structure, thermodynamics and kinetics of the binary and ternary uranium(VI)-ethylenediamine- N,N'-diacetate (in the following denoted EDDA) fluoride systems have been studied using potentiometry, H-1, F-19 NMR spectroscopy and X-ray diffraction. The UO22+ - EDDA system could be studied up to - log[H3O+] = 3.4 where the formation of two binary complexes UO2(EDDA)(aq) and UO2(H(3)EDDA)(3+) were identified, with equilibrium constants log beta(UO(2)EDDA) = 11.63 +/- 0.02 and log beta(UO(2)H(3)EDDA(3+)) = 1.77 +/- 0.04, respectively. In the ternary system the complexes UO2(EDDA) F-, UO2(EDDA)(OH)(-) and (UO2)(2)(mu-OH)(2)(HEDDA)(2)F-2(aq) were identified; the latter through F-19 NMR. H-1 NMR spectra indicate that the EDDA ligand is chelate bonded in UO2(EDDA)(aq), UO2(EDDA) F- and UO2(EDDA)(OH)(-) while only one carboxylate group is coordinated in UO2(H(3)EDDA)(3+). The rate and mechanism of the fluoride exchange between UO2(EDDA) F- and free fluoride was studied by F-19 NMR spectroscopy. Three reactions contribute to the exchange; (i) site exchange between UO2(EDDA) F- and free fluoride without any net chemical exchange, (ii) replacement of the coordinated fluoride with OH- and (iii) the self dissociation of the coordinated fluoride forming UO2(EDDA)(aq); these reactions seem to follow associative mechanisms. H-1 NMR spectra show that the exchange between the free and chelate bonded EDDA is slow and consists of several steps, protonation/deprotonation and chelate ring opening/ring closure, the mechanism cannot be elucidated from the available data. The structure (UO2)(2)(EDDA)(2)(mu-H(2)EDDA) was determined by single crystal X-ray diffraction and contains two UO2( EDDA) units with tetracoordinated EDDA linked by H(2)EDDA in the zwitterion form, coordinated through a single carboxylate oxygen from each end to the two uranium atoms. The geometry of the complexes indicates that there is no geometric constraint for an associative ligand substitution mechanism.

Ort, förlag, år, upplaga, sidor
2006. nr 43, s. 5176-5183
Nyckelord [en]
dioxouranium(vi) complexes, aqueous-solution, uranyl, titrations, mechanisms
Identifikatorer
URN: urn:nbn:se:kth:diva-16101DOI: 10.1039/b608814gISI: 000241679500011Scopus ID: 2-s2.0-33750445264OAI: oai:DiVA.org:kth-16101DiVA, id: diva2:334143
Anmärkning
QC 20100525Tillgänglig från: 2010-08-05 Skapad: 2010-08-05 Senast uppdaterad: 2017-12-12Bibliografiskt granskad

Open Access i DiVA

Fulltext saknas i DiVA

Övriga länkar

Förlagets fulltextScopus

Personposter BETA

Szabo, Zoltan

Sök vidare i DiVA

Av författaren/redaktören
Szabo, ZoltanFischer, Andreas
Av organisationen
Oorganisk kemi
I samma tidskrift
Dalton Transactions

Sök vidare utanför DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetricpoäng

doi
urn-nbn
Totalt: 27 träffar
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf