Propeller‐Shaped Fe4 and Fe3M Molecular Nanomagnets: A Journey from Crystals to Addressable Single Molecules.

This Microreview covers the preparation and investigation of Fe4 and Fe3M complexes with a propeller‐like structure, most of which function as single‐molecule magnets (SMMs). The magnetic characterization of these highly symmetric and chemically versatile complexes has enabled the establishment of important magneto‐structural correlations regarding magnetic anisotropy and magnetic relaxation mechanisms in SMM materials. Their chemical stability and easy functionalization have been further exploited to process them into thin films, down to monolayers and submonolayers, using solution or vapor‐phase methods. The proof so obtained that surface‐supported molecules can largely retain the rich magnetic behavior of bulk phases has been a turning point in SMM research, which has the integration of SMMs into spintronic devices among its most ambitious goals. Tetrairon(III) and related complexes with a propeller‐like structure not only served as excellent benchmark systems for studying single‐molecule magnet (SMM) behavior. They were also crucial to demonstrate that the memory effect of a SMM is not destroyed upon interaction with a metal surface, a result of primary importance in the emerging field of molecular quantum spintronics. [ABSTRACT FROM AUTHOR]