Field-induced slow magnetic relaxation in a mononuclear Dy(III) complex with octahedral geometry

We have synthesized a mononuclear Dy(III)-based complex, [Dy(CyPh2PO)3Cl3)] 2 PO) 3 Cl 3 )] (1) 1 ) (CyPh2PO 2 PO = cyclohexylbisphenylphosphine oxide), constructed from a phosphine oxide ligand and a light halogen Cl donor. The Dy(III) ion presents an octahedral geometry where two O atoms from two phosphine ligands locate at two vertexes, while the equatorial positions are completed by three Cl anions and a O atom from another phosphine ligand. Magnetism results reveal that slow relaxation of the magnetizations exists in 1 under an extra dc field because of the significant quantum tunnelling of magnetization (QTM) at 0 Oe dc field. The lighter Cl ions in equatorial plane result in a larger effect to QTM, and thus smaller contribution to slow magnetic relaxation.