Dipotassiumtetrachloride-bridged dysprosium metallocenes: a single-molecule magnet.

The present work describes the dynamic magnetic properties of the complex [(Cp)DyIII2ClK]·3.5(CH) (1), synthesized by employing a tri-aryl-substituted cyclopentadienyl ligand (Cp), [4,4'-(4-phenylcyclopenta-1,3-diene-1,2-diyl)bis(methylbenzene) = CpH]. Each Dy(III)-metallocene weakly couples KCl, displaying slow relaxation of magnetization below 14.5 K under zero applied dc field KD3 energy levels with an energy barrier of 136.9/133.7 cm on the Dy sites. The single-ion axial anisotropy energy barrier is reduced by geometrical distortion due to the coordination of two chloride ions at each Dy centre.