Construction of high-performance single-molecule magnets with a high-axiality coordination environment surrounding a lanthanide spin center based on macrocyclic ligands.

With the advent of the information age, a pressing imperative for larger capacity, higher speeds and miniaturized devices to process and store information is emerging. Single-molecule magnets (SMMs), as molecular nanomagnets with a unique ability to exhibit both classical magnetic relaxation and quantum tunneling at the molecular level, are considered promising candidates for higher storage density magnetic materials and qubit computing. In recent years, SMMs with excellent performance have emerged in an endless stream. Especially, many breakthroughs have been achieved using SMMs based on macrocyclic ligands, where inherent structural advantages provide a shortcut for the construction of highly axisymmetric configurations, which is the key to developing high-performance SMMs. Herein, we review the recent research on lanthanide-based macrocyclic SMMs with D5h and D6h symmetry, classify them according to the characteristics of macrocyclic structures, and further summarize the magneto-structural correlations of macrocyclic SMMs. We also propose building a modifiable precursor module for obtaining highly axially symmetric macrocyclic structures. This review provides theoretical guidance for preparing and designing high-performance SMMs from the perspective of specific macrocycles, highlighting the potential of macrocyclic ligands in advancing the field.