1. New Strategies for Incorporating Magnetic Anisotropy into Single-Molecule Magnets
Matthew P. Shores, Department of Chemistry, Colorado State University
For nearly 15 years, the potential for molecular species to be used as magnetic bits has been thwarted by the very low temperatures required (~4 K) to observe the bistability phenomenon. Our research focuses on the synthesis of inorganic and organometallic complexes that have discotic or linear shapes. This shape anisotropy is intended to drive magnetic anisotropy, which is required for single-molecule magnet behavior, but difficult to control.
[(cyclam)2Co2Cl2(DEB)]2+
[(cyclam)3Co3Cl3(TEB)]3+
We have found that the reaction of trans-[Co(cyclam)Cl2]Cl (cyclam = 1,4,8,11-tetraazacyclotetradecane) with di- and tri-ethynylbenzene in methanol in the presence of weak bases yield discrete mono-, di-, and tri-Co(III)-ethynylbenzene architectures. These species have been characterized by ES-MS, FT-IR and X-ray crystallography, and are stable in air and in solution. Although these particular examples are diamagnetic, they offer a template for preparing paramagnetic analogues, and may serve as core precursors for the controlled growth of larger assemblies capable of SMM behavior at more technologically relevant temperatures.