Structures and Single-Molecule Magnet Behavior of Dy and Dy Clusters Constructed by Different Dysprosium(III) Salts.

Using the Schiff base ligand HL-pyra ('-(2-hydroxybenzoyl)pyrazine-2-carbohydrazonamide) with multiple dentate sites, the trinuclear Dy-based complex [Dy(HL-pyra)(L-pyra)(CHCOO)]·2HO () was synthesized. By analyzing the fragmented assembly process and fine-tuning the bridging anions, complex [Dy(HL-pyra)(L-pyra)(NO)(HO)]·8HO () with different nuclear numbers was successfully synthesized. Magnetic studies demonstrated that did not exhibit magnetic relaxation behavior under the external field; however, exhibited zero-field single-molecule magnetic relaxation behavior with an effective energy barrier () of 197.44 K. This is attributed to the improved anisotropy of the single ion after the normalization of the crystal structure, thus realizing the molecular magnetic switching. Moreover, magnetic dilution analysis of demonstrated that the weak magnetic interaction between metal ions inhibited the occurrence of quantum tunneling of magnetization (QTM), resulting in high-performance single-molecule magnet (SMM) behavior. The reasons for the magnetic difference between these two complexes were analyzed using calculation and magneto-structural correlations. This study provides a reasonable prediction of the ideal configuration of the approximately parallelogram Dy-based SMMs, thus offering an effective approach for synthesizing Dy complexes with excellent properties.