| Numéro |
J. Phys. IV France
Volume 7, Numéro C2, Avril 1997
Proceedings of the 9th International Conference on X-Ray Absorption Fine Structure
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|---|---|---|
| Page(s) | C2-619 - C2-620 | |
| DOI | https://doi.org/10.1051/jp4/1997116 | |
J. Phys. IV France 7 (1997) C2-619-C2-620
DOI: 10.1051/jp4/1997116
In Situ X-Ray Absorption Studies of the Electrochemical Reduction of Hydroxocobalamin
M. Giorgett1, 2, I. Ascone1, M. Berrettoni3, S. Zamponi2 and R. Marassi21 LURE, Bât. 209D, Université de Paris-Sud, 91405 Orsay, France
2 Dip. Scienze Chimiche, via S. Agostino 1, 62032 Camerino (MC), Italy
3 Dip. Matematica e Fisica, via Madonna delle Carceri, 62032 Camerino (MC), Italy
Abstract
XAS fluorescence is combined with electrochemical technique to study the reduction of
hydroxocobalamin (OH-Co(III)cbl) to cob(II)alamin at the cobalt K-edge. The electrochemical control permits to
select a well-defined cobalt oxidation states. The experimental set-up used permits in situ reactions allowing
reliable comparison among XANES spectra. The absorption edge shifts to lower energy with the progressive
reduction of cobalt. The size of the peak at about 7726 eV (A peak) decrease in Co(II)cbl spectrum. Experimental
XANES of OH-Co(ITI)cbl and Co(II)cbl were simulated by multiple scattering theory. Theoretical and experimental
data are in agreement, peak intensity being correlated to the coordination number confirming that cobalt is five
coordinate in Co(II)cbl sample.
© EDP Sciences 1997