A Terminal Fluoride Ligand Generates Axial Magnetic Anisotropy in Dysprosium Complexes

The first dysprosium complexes with a terminal fluoride ligand are obtained as air‐stable compounds. The strong, highly electrostatic dysprosium–fluoride bond generates a large axial crystal‐field splitting of the J=15/2 ground state, as evidenced by high‐resolution luminescence spectroscopy and correlated with the single‐molecule magnet behavior through experimental magnetic susceptibility data and ab initio calculations. A strong donor terminal fluoride ligand generates large crystal‐field splittings within dysprosium(III) complexes and gives rise to new air‐stable single molecule magnets with large barriers to magnetic relaxation. High‐resolution luminescence spectroscopy data are presented and correlated with the single‐molecule magnet behavior through experimental magnetic susceptibility data and ab initio calculations.