Structural correlations between the crystal field and magnetic anisotropy of Ln–Cu single-molecule magnets

Mixed ligand Ln2Cu2 tetranuclear complexes, [{LnCu(L4)(L5)(NO3)2}2] (L4− is a Schiff base ligand derived from o-vanilate, L52− is a nitromethyl derivative of L4−; LnGd(4), Tb(5), and Dy(6)), were synthesized by reacting the corresponding dinuclear complexes [LnCu(o-vanilate)2(NO3)3] with ethylamine in a nitromethane solution. From detailed studies of magnetic anisotropies 5 was shown to behave as an SMM, whereas 6 was not an SMM.