Synthesis, Structure, and Magnetic Properties of Homometallic Mono-, Penta-, and Hexanuclear Dysprosium Complexes

Regulation of the complex structure is greatly significant for the preparation of single-molecule magnets (SMMs). A Schiff base ligand, having suitably flexible coordination pockets, is usually designed to construct SMMs. In this text, three new homometallic complexes ([Dy(HL)2](NO3)center dot 2H2O (Dy1), [Dy5(L)4(CH3CO2)6](CH3CO2)center dot 6MeOH center dot H2O (Dy5), and [Dy6(L)2(L1)2(u3-OH)4(CF3SO3)6(EtOH)4]center dot 2EtOH (Dy6)) were synthesized based on a Schiff base ligand, 6,6 '-dimethoxy-2,2 '- [4,5-dimethyl-o-phenylenebis(nitrilomethylidyne)]-diphenol (H2L), which has an N2O2 pocket and a certain extent of steric hindrance. Their structures are characterized by single-crystal X-ray diffraction, and their magnetic properties are also explored. Complex Dy1 is a double-decker structure in which the Dy ion is sandwiched by two HL- ligands. Complex Dy5 displays a helical quadruple-decker structure which can be regarded as the structural extension of complex Dy1 but this is terminated by the coordination of acetate groups. Complex Dy6 is a centrosymmetric hexanuclear structure in which three Dy(III) ions construct an independent triangular plane. The new ligand L12- (H2L1 = 2-(hydroxymethyl)-6-methoxyphenol) in complex Dy6 is produced in situ from H2L under hydrothermal conditions. Magnetic studies on these complexes revealed that both Dy1 and Dy6 are typical SMMs, with a Ueff/kB value of 38.4 K for Dy1 and 33.6 K for Dy6, respectively, and complex Dy5 also shows SMM behavior under a zero dc field.

Automated summary

In this study, three new homometallic complexes were synthesized based on a Schiff base ligand, and their structures and magnetic properties were explored. Complexes Dy1 and Dy6 exhibited typical single-molecule magnet behavior, while complex Dy5 showed single-molecule magnet behavior under a zero dc field.