Discrete metal complexes from N-heterocyclic ferrocenes: Structural diversity by ligand design

Abstract The aim of this review is to provide an overview of the structures of discrete metal complexes with N -heterocyclic ferrocenes, based on their crystal structures. These N -heterocyclic ferrocenes act as versatile ligands for the construction of metal complexes with unique structures, owing to the π⋯π interaction between the N -heterocycles and conformational flexibility of the ferrocenyl moiety. N -Heterocyclic ferrocenes coordinate to metal ions in monodentate, C,N-bidentate, multidentate, and bridging fashions, which results in metal complexes with various M:L stoichiometry. The ligands and their metal complexes have been recently employed for applications including chemical sensors, homogeneous catalysts, and redox-driven conformational switching.