The biological and medicinal chemistry of bismuth

Bismuth compounds have been widely used in medicine for more than 200 years, and new bismuth-containing drugs are now being developed. However the biological chemistry of bismuth is poorly understood. We review here methods for the study of bismuth compounds, and use of Bi(III) in antiulcer, antibacterial, anti-HIV and radiotherapeutic agents is described. The chemistry of Bi(III) carboxylates and amino-carboxylates is dominated by intermolecular interactions which lead to polymeric structures. Bi(III) exhibits a highly variable coordination number and coordination geometry, and alkoxide ligands can induce a strong stereochemical ''lone-pair effect''. Bi(III) can bind to both Zn(II) sites (e.g. metallothionein) and Fe(III) sites (e. transferrin) in proteins. Further work is needed to understand the relationship between the structures and dynamics of bismuth compounds and their bioactivity.