Uptake of VIV ion of vanadocene dichloride by apo-transferrin investigated by ESR spectroscopy

The action mechanism of vanadocene dichloride, Cp2VCl2 (Cpdouble bond; length as m-dashη5-C5H5), has been investigated by interaction with apo-transferrin and albumin for its promising antitumor activities. Our ESR spectral studies clearly showed that VIV ion is readily transported from vanadocene chloride to transferrin, and the VIV ions are captured at the Fe(III) binding sites of transferrin as a VO2+ form. We also observed that some binuclear VO2+ complexes can efficiently transport the VO2+ ions to the apo-transferrin.