Preparation and anti-tumour activity of some arylbismuth(iii) oxine complexes

Abstract

New arylbismuth(III) oxinates, PhBi(MeOx)2, (p-MeC6H4)Bi(Ox)2, (p-MeC6H4)Bi(MeOx)2, (p-CIC6H4)Bi(Ox)2, and (p-CIC6H4)Bi(MeOx)2 (Ox- = quinolin-8-olate and MeOx- = 2-methylquinolin-8-olate) have been prepared by reaction of the appropriate diarylbismuth chlorides with Na(Ox) or Na(MeOx) in the presence of 15-crown-5. An X-ray crystallographic study has shown PhBi(MeOx)2 to be a five coordinate monomer with distorted square pyramidal stereochemistry. Chelating MeOx ligands have a cisoid arrangement in the square plane and the phenyl group is apical. The lattice is stabilised by significant Π-Π interactions between centrosymmetric molecules. A range of these complexes has been shown to have high in vitro biological activity (comparable with or better than cisplatin) against L1210 leukaemia, the corresponding cisplatin resistant line, and a human ovarian cell line, SKOV-3. However, initial in vivo testing against a solid mouse plasmacytoma (PC6) and P388 leukaemia has not revealed significant activity.