A Dy2 single-molecule magnet with benzoate anions and phenol-O(-) bridging groups.

A Dy2 single-molecule magnet, namely [Dy2(H3L)2(PhCOO)4]·4H2O (1), was obtained from the reaction of Dy(PhCOO)3 with 1,5-bis(2-hydroxy-3-methoxybenzylidene)carbonohydrazide (H4L). Each Dy(III) ion is located in the chelating pocket [DyO8N] formed by the carboxyl-O, phenol-O, carbohydrazide-O and carbohydrazide-N, forming a tricapped trigonal prism configuration. The Dy(III) centers are bridged by the benzoate anions with μ2:η(1),η(2) coordination mode and the phenol-O(-) groups in the form of μ1:η(2), respectively. The appearance of frequency-dependent out-of-phase (χ''M) signals indicates that 1 displays single-molecule magnet (SMM) behaviour. Fits of the ac data gave an energy barrier (Ueff) of 42.7 K with a pre-exponential factor (τ0) of 1.31 × 10(-7) s. The structure-property relationship of some selected Dy2 paradigmatic compounds was further discussed.