Ruthenium and iron metallodrugs: new inorganic and organometallic complexes as prospective anticancer agents

Abstract In this chapter we address the development of ruthenium- and iron-based metallodrugs as prospective chemotherapeutics in cancer treatment. We provide an overview of the field addressing iron and ruthenium complexes reported as promising anticancer metallodrug candidates, their properties and specific features, and mostly focus on newer contributions in this field (including synthetic routes often followed), which include “classical” coordination complexes and organometallic compounds. The first group comprises Fe(III) and Ru(III) complexes with octahedral geometry and a tetradentate ligand, namely ternary tripodal aminobisphenolates and cyclam derivatives for Fe(III) or salen- and salan-like ligands for Ru(III). In the larger group of organometallic complexes, we highlight the value of the “M(Cp)” scaffold in metallodrug design (M being Ru(II) and Fe(II), and Cp being η5-cyclopentadienyl) and provide examples of very effective compounds with modes of action that are distinct from those of Pt-based drugs in clinical use, including some “Ru(Cp)” complexes with the ability to overcome multidrug resistance mechanisms.