Controlled metal nanostructures: Fertile ground for coordination chemists

Abstract Composition (metal or metal oxide core and organic coating), size, shape and structure are the main parameters governing the properties of nano-objects. Driven by their huge potential for application in fields as diverse as catalysis, energy, environment, electronics and medicine much research effort has been dedicated to the control of these parameters over the past 30 years. Namely, the use of concepts and techniques of molecular chemistry has provided remarkable advances in the growth of well-defined nanostructures by pointing out the key roles played by both the metal precursors and stabilizing agents (polymers, dendrimers, ionic liquids, ligands, etc .) during the three main steps of the formation of nanostructures: release of metal atoms, nucleation and growth. It is now currently admitted that interaction between the precursor and stabilizing agent may generate intermediate complexes in the reacting medium which may change the course of the reaction. Also, coordination of the ligand on the growing seeds is recognized as an important factor influencing the growth of nanostructures. Finally, coordination of the ligand at the surface of nanostructures may induce a change in their physical and chemical properties by tuning electronic density and steric hindrance at their surface. To illustrate these points, this review will focus on metal nanostructures synthesized in organic solutions from molecular metal complexes as metal sources and stabilized by coating ligands, short chain molecules with headgroups able to coordinate onto the metal surface. Recent advances will be described highlighting the incidence of coordination chemistry through a selection of relevant examples from the literature.