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 state. 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(III)cbl) and cob(II)cbl were simulated by multiple scattering theory. Theoretical and experimental data are in agreement, peak intensity being correlated to the coordinatio number confirming that cobalt is five coordinate in Co(IICBL sample.
In situ X-Ray absorption studies of the electrochemical reduction of hydroxocobalamin
M. Berrettoni;ZAMPONI, Silvia;MARASSI, Roberto
1997-01-01
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 state. 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(III)cbl) and cob(II)cbl were simulated by multiple scattering theory. Theoretical and experimental data are in agreement, peak intensity being correlated to the coordinatio number confirming that cobalt is five coordinate in Co(IICBL sample.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
