3d Ion-Driven Hexanuclear Heterometallic Clusters with Amazing Structures and Magnetic Properties

By using a heptadentate Schiff base ligand with three NO 2 pockets to react with 3d and 4f acetate precursors, three series of M 4 Ln 2 complexes (M, Ln = Ni, Gd for 1 NiGd; Ni, Dy for 2 NiDy; Co, Gd for 3 CoGd; Co, Dy for 4 CoDy; Cu, Gd for 5 CuGd; Cu, Dy for 6 CuDy ) have been obtained and characterized. X-ray single-crystal diffraction analyses indicated that Ni 4 Ln 2 series exhibit butterfly structures with extended wings, the Co 4 Ln 2 series are made up of four fused linear defective open cubes, and the Cu 4 Ln 2 series display H-typed topology structures. The dc magnetic susceptibility data revealed that all of the Gd derivatives possess significant magnetic entropy change, whereas the alternating current (ac) magnetic susceptibility measurements identified that only the NiDy derivative displays single-molecule magnet behavior with energy barrier of 15.69 K under zero dc field. These results reveal that 3d ions are important in adjusting the structure and magnetic properties for 3d–4f complexes.