Dipotassiumtetrachloride-bridged dysprosium metallocenes: a single-molecule magnet

The present work describes the dynamic magnetic properties of the complex [(Cp^Ar3)₄Dy^III₂Cl₄K₂]·3.5(C₇H₈) (1), synthesized by employing a tri-aryl-substituted cyclopentadienyl ligand (Cp^Ar3), [4,4′-(4-phenylcyclopenta-1,3-diene-1,2-diyl)bis(methylbenzene) = Cp^Ar3H]. Each Dy(III)-metallocene weakly couples via K₂Cl₄, displaying slow relaxation of magnetization below 14.5 K under zero applied dc field via KD3 energy levels with an energy barrier of 136.9/133.7 cm⁻¹ 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.