Abstrakt
A series of vanadocene complexes [Cp´2V(L)][OTf]2 (Cp´ = 5-C5H5, 5-C5H4Me; L = phen, 5-NO2-phen, 5-NH2-phen, 4,7-Ph2-phen) was prepared and characterized by mass spectrometry and EPR spectroscopy. Structures of two complexes that contain an N,N-chelating ligand, [(5-C5H4Me)2V(phen)][OTf]2 center dot 0.5Me2CO and [(5-C5H5)2V(5-NH2-phen)][OTf]2, and the triflate intermediate [(5-C5H5)2V(OTf)2] were further confirmed by X-ray diffraction analysis.
The cytotoxicity study has shown that complexes that contain phenanthroline ligands have considerably higher in vitro activity toward human leukemia cells MOLT-4 and HL-60 than their parent dichlorides ([Cp2VCl2]). The high activity of these complexes coheres with their higher stability in various aqueous media.
This study has further shown that substitution of chloride ligands in the vanadocene dichloride has a considerably higher effect on cytotoxicity than expected on the basis of established mechanistic rules.