A half-sandwich organometallic single-ion magnet with hexamethylbenzene coordinated to the Dy(III) ion.

A half-sandwich organolanthanide complex, [(C6Me6)Dy(AlCl4)3], in which Dy(III) is coordinated with a π-bonded arene was synthesized and magnetically characterized. This complex displays slow magnetic relaxation and a hysteresis loop associated with single-ion magnet behavior. The orientation of the magnetic anisotropy axis is analyzed using ab initio calculations.