Nickel(II)-Lanthanide(III) Magnetic Exchange Coupling Influencing Single-Molecule Magnetic Features in {Ni2Ln2} Complexes

Four isostructural [Ni(2)Ln(2)(CH3CO2)(3)(HL)(4)(H2O)(2)](3+)(Ln(3+)=Dy (1), Tb (2), Ho (3) or Lu (4)) complexes and a dinuclear [NiGd(HL)(2)(NO3)(3)] (5) complex are reported (where HL=2-methoxy-6-[(E)-2-hydroxymethyl-phenyliminomethyl]-phenolate). For compounds 1-3 and 5, the Ni2+ ions are ferromagnetically coupled to the respective lanthanide ions. The ferromagnetic coupling in 1 suppresses the quantum tunnelling of magnetisation (QTM), resulting in a rare zero dc field Ni-Dy single-molecule magnet, with an anisotropy barrier U-eff of 19K.