Back to the future of organolanthanide chemistry

At the dawn of the development of structural organometallic chemistry, soon after the discovery of ferrocene, the description of the LnCp(3) complexes, featuring large and mostly trivalent lanthanide ions, was rather original and sparked curiosity. Yet, the interest in these new architectures rapidly dwindled due to the electrostatic nature of the bonding between pi-aromatic ligands and 4f-elements. Almost 70 years later, it is interesting to focus on how the discipline has evolved in various directions with the reports of multiple catalytic reactivities, remarkable potential in small molecule activation, and the development of rich redox chemistry. Aside from chemical reactivity, a better understanding of their singular electronic nature - not precisely as simplistic as anticipated - has been crucial for developing tailored compounds with adapted magnetic anisotropy or high fluorescence properties that have witnessed significant popularity in recent years. Future developments shall greatly benefit from the detailed reactivity, structural and physical chemistry studies, particularly in photochemistry, electro- or photoelectrocatalysis of inert small molecules, and manipulating the spins' coherence in quantum technology.

Automated summary

At the beginning of the development of structural organometallic chemistry, the interest in LnCp(3) complexes quickly diminished due to the electrostatic nature of bonding between pi-aromatic ligands and 4f-elements. However, over the past 70 years, this field has evolved in various directions, showing multiple catalytic reactivities, potential in small molecule activation, and rich redox chemistry. Understanding their electronic nature has been crucial for developing compounds with tailored magnetic and fluorescence properties that have gained popularity in recent years. Future developments will benefit from detailed studies in reactivity, structure, and physical chemistry, particularly in photochemistry, electro- or photoelectrocatalysis, and quantum technology spin manipulation.