Assembling Dysprosium Dimer Units into a Novel Chain Featuring Slow Magnetic Relaxation via Formate Linker

A dinuclear
complex [DyLCl­CH3­OH)]2 (1) and a one-dimensional compound [DyL­(HCOO)­(CH3­OH)]n (2) have been
synthesized using an organic ligand of N′-(2-hydroxy­benzyl­idene)­picolino­hydra­zide
(H2L). Complex 1 exhibits a symmetric dinuclear
structure, in which the Dy3+ centers reside in a pentagonal-bipyramidal
coordination environment. In 2, the dinuclear units of 1 are strung into chains by formate anions, in which Dy3+ ions are situated in an octa-coordinated, hula-hoop-like
coordination geometry. Magnetic studies reveal that ferromagnetic
coupling is found between Dy3+ ions in both compounds.
Complexes 1 and 2 exhibit slow magnetic
relaxation under zero dc field with effective energy barriers of 88.4
and 175.8 K, respectively. Magnetic study combined with ab initio
calculations indicates that the better performance of 2 is related to the unique molecular geometry and relatively stronger
Dy3+–Dy3+ magnetic interaction within
and/or between the dimer units.