Synthesis, characterization and cytotoxic effect of vanadocene complexes bearing substituted 2,2′-bipyridines and 4,5-diazafluoren-9-one

Abstract

This study describes the synthesis of vanadocene compounds [Cp′2V(L)][OTf]2, where Cp′ is substituted cyclopentadienyl ring and L is N,N-chelating ligand. All prepared compounds were characterized by analytical and spectroscopic methods. The structures of [(η5-C5H4Me)2V(bpy)][OTf]2, [(η5-C5H4iPr)2V(bpy)][OTf]2·CH2Cl2, [Cp2V(4,4′-Me2-bpy)][OTf]2, [Cp2V{4,4′-(MeO)2-bpy}][OTf]2·MeOH and [(η5-C5H4Me)2V(dafone)][OTf]2 were further confirmed by the X-ray diffraction analysis. The cytotoxicity study, performed on human leukemia cells MOLT-4 and HL-60, demonstrates that the activity of the vanadocene complexes strongly depends on the nature of the coordinated chelating ligand. The high cytotoxicity was observed for the complex bearing 2,2′-bipyridine, [(η5-C5H4Me)2V(bpy)][OTf]2, that shows IC50 values close to the data observed for cisplatin.