Four Ni-Ln-Ni heterometallic complexes, [Ni2LnL2]NO3·3H2O (H3L = tri(((3-methoxysalicylidene)amino)ethyl)amine, Ln = Gd for , Tb for and Dy for , respectively) and [Ni2DyL2]ClO4·MTBE·0.65H2O (, MTBE = methyl tert-butyl ether) have been synthesized by diffusion of methyl tert-butyl ether vapor into the reaction solution. The X-ray analyses demonstrated that the Gd(III) ion in exhibits rare seven-coordination, the Tb(III) and Dy(III) ions in display unusual six-coordination, and two Ni(II) ions and one Ln(III) ion are bridged by six phenolato atoms to form linear Ni-Ln-Ni heterotrinuclear complexes for . All complexes exhibit weak ferromagnetic interactions between Ni(II) and Ln(III) ions. Alternating current susceptibility measurements demonstrated that compounds and behave as single-molecule magnets with the effective energy barriers of 14.17 and 11.13 K under zero direct current field. They are rare single-molecule magnets containing six-coordinate Dy(III) ions.

By using a salen-type ligand and changing the reaction solvent, a series of NiII–LnIII complexes have been obtained and structurally and magnetically characterized.

By using the azide anion, hexafluoroacetylacetonato anion (hfac) and compartmental Schiff-base ligand H 2 valpn (H 2 valpn = 1,3-propanediylbis(2-iminomethylene-6-methoxy-phenol), three isomorphous Ni-Ln heterodinuclear complexes [Ni(valpn)Gd(hfac) 2 N 3 (H 2 O) 2 ]·H 2 O (1), [Ni(valpn)Tb(hfac) 2 N 3 (H 2 O) 2 ]·H 2 O (2) and [Ni(valpn)Dy(hfac) 2 N 3 (H 2 O) 2 ]·H 2 O (3) were synthesized. Structural analyses reveal that the Ni(II) and Ln(III) ions are doubly bridged by two phenoxo oxygen atoms of the valpn ligand. Magnetic susceptibility measurements show ferromagnetic couplings are operative between the Ni(II) andLn(III) ions in 1−3. Ac susceptibility measurements under a dc-applied field of 1000Oe disclose that the Dy derivative exhibits the field-induced single-molecule magnet behavior with effective energy barrier of 16.9 K for reversal of the magnetization.

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