3d single-ion magnets

• Published in: Chemical Society reviews 2015-04, Vol.44 (8), p.2135-2147
• Main Authors: Craig, Gavin A, Murrie, Mark
• Format: Article
• Language: English
• ISSN: 0306-0012; 1460-4744
• DOI: 10.1039/c4cs00439f

One of the determining factors in whether single-molecule magnets (SMMs) may be used as the smallest component of data storage, is the size of the barrier to reversal of the magnetisation, U eff . This physical quantity depends on the magnitude of the magnetic anisotropy of a complex and the size of its spin ground state. In recent years, there has been a growing focus on maximising the anisotropy generated for a single 3d transition metal (TM) ion, by an appropriate ligand field, as a means of achieving higher barriers. Because the magnetic properties of these compounds arise from a single ion in a ligand field, they are often referred to as single-ion magnets (SIMs). Here, the synthetic chemist has a significant role to play, both in the design of ligands to enforce propitious splitting of the 3d orbitals and in the judicious choice of TM ion. Since the publication of the first 3d-based SIM, which was based on Fe( ii ), many other contributions have been made to this field, using different first row TM ions, and exploring varied coordination environments for the paramagnetic ions. This review describes the recent approach to obtain single-molecule magnets where the magnetic properties arise from just one first row transition metal ion in a suitable ligand field.