A number of strategies are being pursued for the synthesis of new single-molecule magnets exhibiting high blocking temperatures. Mononuclear transition metal complexes with a low coordination number and appropriate electron configuration can exhibit large orbital contributions to the magnetism, resulting in effective spin relaxation barriers as high as 226 cm–1. The unquenched orbital angular momentum inate to the electronic structures of lanthanide ions such as Tb3+, Dy3+, and Er3+, enable the design of large relaxation barriers in mononuclear complexes through matching of the ligand field to the MJ level shape anisotropy. Further, the use of radical bridging ligands such as N23– and [2,2′-bipyrimidine]•– can lead to strong magnetic exchange coupling with lanthanide ions, supressing quantum tunneling processes and resulting in molecules that display magnetic hysteresis up to a record of 14 K. Some new actinide-based single-molecule magnets and the prospects for achieving large relaxation barriers in such species will also be discussed.

New single-molecule magnets with high blocking temperatures

249th National Meeting (2015)

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