Ligand field and anion-driven structures and magnetic properties of dysprosium complexes

Based on the organic ligand 2,2'-(((pyridine-2,6-diylbis(methylene))bis((pyridin-2-ylmethyl)-azanediyl))-bis(methylene))diphenol (H2L), and dysprosium salts with different anions, two mononuclear and one dinuclear complexes, namely, (Dy(L)(H2O)](ClO4)center dot 2CH(3)CH(2)OH (1), (Dy(L)(NO3)] (2) and [Dy-2(L)(dbm)(4)] (3, Hdbm = dibenzoylmethane), were synthesized and structurally and magnetically characterized. In complexes 1 and 3, the Dy centers are octa-coordinated with triangular dodecahedral (local D-2d symmetry) environments. Complex 1 is dimeric by hydrogen bond interactions between coordinated water molecules. In complex 3, two Dy-III ions are linked by two phenoxy oxygen atoms to form a dinuclear cluster. The Dy-III ion in complex 2 is nine-coordinated and adopts a spherical capped square antiprism geometry with a C-4v symmetry. Magnetic measurements and theoretical calculations reveal that the magnetic couplings between two phenoxyl-bridging Dy-III ions in complex 3 are antiferromagnetic and mostly originate from the exchange coupling. Both complexes 1 and 2 exhibit single molecule magnet behaviors under zero direct-current field with effective energy barriers of 50.94 K and 12.26 K, respectively. Complex 3 only exhibits frequency-/temperature-dependent out-of-phase signals, and no peak is observed.

Automated summary

Based on the organic ligand H2L and dysprosium salts with different anions, two mononuclear and one dinuclear complexes were synthesized and structurally and magnetically characterized. The complexes exhibit different coordination environments for the dysprosium centers, with complex 1 and 3 being octa-coordinated and complex 2 being nine-coordinated. Magnetic measurements and theoretical calculations show unique magnetic behaviors for each complex.