Multi-Ferrocene-Based Ligands: From Design to Applications.

Despite the extensive literature on ferrocene chemistry, a comprehensive analysis of multiferrocene ligands is notably absent. Thus, this review presents an overview of multiferrocenyl-containing ligands, focusing on their synthesis, characterization, and applications in catalysis and sensing. These ligands offer unique properties, including redox activity and planar chirality, making them valuable in asymmetric catalysis and molecular electronics. The review covers the literature from the first synthesis of tris(ferrocenyl)phosphane in 1962 to current developments, including various ligand subsets, which contain at least two ferrocene units within their structure. Special attention is given to explaining the coordination chemistry, electrochemical behavior, and practical applications of these ligands. The aim of this undertaking is to fill gaps in knowledge and inspire further research by identifying areas for exploration. Notably, certain ligand families like TRAP (-spanning phosphane) ligands remain underexplored in terms of their electrochemical properties, highlighting opportunities for future investigation. Thus, this review provides a resource for researchers in the field, stimulating further advancements in multiferrocenyl ligand chemistry and its wide-ranging applications.