Predicting Magnetic Barriers in Lanthanide Complexes with Electrostatic Potential Charges

Single-molecule magnets (SMMs) with slow relaxation of
magnetization
and blocking temperatures above that of liquid nitrogen are essential
for practical applications in high-density data storage devices and
quantum computers. A rapid and accurate prediction of the effective
magnetic relaxation barrier (Ueff) is
needed to accelerate the discovery of high-performance SMMs. Using
density functional theory and multireference calculations, we explored
correlations between Ueff, partial atomic
charges, and the anisotropic barrier for a series of sandwich-type
lanthanide complexes containing cyclooctatetraene, substituted cyclopentadiene,
phospholyl, boratabenzene, or borane ligands. Our results show a correlation
between the electrostatic potential charge of the lanthanide ion in
the complex and Ueff. Systematic ligand
modifications show that reducing ligand nucleophilicity and incorporating
soft bases enhance magnetic anisotropy and Ueff values. This work identifies a correlation to predict Ueff values and optimization of ligand coordination
environments in lanthanide-based SMMs.