Actinide-based single-molecule magnets: alone or in a group?

In recent years, very significant progress has been made in single-molecule magnets (SMMs), and one of the major milestone works is the hysteresis blocking temperature beyond the boiling point of liquid nitrogen. As increasingly abundant experimental and theoretical cases are studied, our understanding of how to construct high-performance rare-earth SMMs is becoming clearer, while few good SMMs have been reported for actinides that possess stronger spin–orbital coupling than rare earths. Recently, attempts to replicate the successful strategy on rare-earth SMMs to actinides have proven to be a failure, or at least frustrating, with the main reason being the stronger covalent contribution in the actinide-ligand bonds. In this review, the progress on actinide SMMs is summarized to look back at how far we have come and try to find possible routes forward.