Pursuit of Record Breaking Energy Barriers: A Study of Magnetic Axiality in Diamide Ligated Dy^III Single-Molecule Magnets

Dy^III single-ion magnets (SIMs) with strong axial donors and weak equatorial ligands are attractive model systems with which to harness the maximum magnetic anisotropy of Dy^III ions. Utilizing a rigid ferrocene diamide ligand (NN^TBS), a Dy^III SIM, (NN^TBS)­DyI­(THF)₂, 1-Dy (NN^TBS = fc­(NHSitBuMe₂)₂, fc = 1,1′-ferrocenediyl), composed of a near linear arrangement of donor atoms, exhibits a large energy barrier to spin reversal (770.8 K) and magnetic blocking (14 K). The effects of the transverse ligands on the magnetic and electronic structure of 1-Dy were investigated through ab initio methods, eliciting significant magnetic axiality, even in the fourth Kramers doublet, thus demonstrating the potential of rigid diamide ligands in the design of new SIMs with defined magnetic axiality.