Structure and dynamics in the complex ion (UO2)(2)(CO3)(OH)(3)(-)
2000 (English)In: Journal of the Chemical Society. Dalton Transactions, ISSN 1472-7773, E-ISSN 1470-479X, no 18, 3158-3161 p.Article in journal (Refereed) Published
The structure and ligand exchange dynamics of the ternary complex (UO2)(2)(CO3)(OH)(3)(-) have been investigated by EXAFS and NMR spectroscopy. Very broad signals can be observed in both the C-13 and the O-17 NMR spectra. The EXAFS data show the presence of 1.3 +/- 0.3 short uranium-oxygen distances at 2.26 Angstrom, consistent with single bonded hydroxide and 3.9 +/- 0.6 distances at 2.47 Angstrom for the other ligands in the first co-ordination shell. There is also evidence for a U ... U interaction at 3.90 Angstrom. Based on the EXAFS and NMR data we suggest the presence of three isomers with different bridge arrangements, the dominant one, C, contains 80% of the uranium and the minor ones A and B, 5 and 15%, respectively. The ligand exchange reactions between these isomers are slow. The NMR data indicate that the main reactions involve intramolecular exchanges between isomers with different positions of the non-bridging ligands in A, B and C. We suggest that these take place through water exchange as discussed earlier for other ternary uranium(VI) complexes.
Place, publisher, year, edition, pages
2000. no 18, 3158-3161 p.
uranyl-ion, dioxouranium(vi) complexes, equilibrium dynamics, aqueous-solution, nmr, spectroscopy, mechanisms, raman, exafs
IdentifiersURN: urn:nbn:se:kth:diva-20015DOI: 10.1039/b001561jISI: 000089170200019OAI: oai:DiVA.org:kth-20015DiVA: diva2:338708
QC 201005252010-08-102010-08-10Bibliographically approved