Two mononuclear dysprosium(iii) complexes with their slow magnetic relaxation behaviors tuned by coordination geometry

Abstract

Two mononuclear dysprosium(III) complexes [Dy(H₃NAP)₂Cl₂]Cl·EtOH (1) and [Dy(H₃NAP)₂(H₂O)Cl₂]Cl·−2CH₃CN·MeOH·0.5H₂O (2) were obtained by coordinating an in situ formed Schiff base ligand of 1,3-bis(2-hydroxynaphthalenemethyleneamino)-propan-2-ol (H₃NAP) to the dysprosium(III) ion. Their Dy(III) centers are six and seven-coordinated in octahedral and pentagonal–bipyramidal coordination geometries, respectively. Their structural difference is caused by the additional coordinated water molecule in the equatorial positions of complex 2 in comparison with that of complex 1. The well designed semi-rigid ligand contributes significantly to the low coordination numbers of Dy(III) ions in the two title complexes, as well as to their structural difference. Magnetic investigations revealed that complexes 1 and 2 are both field-induced single-ion magnets (SIMs) with their effective energy barriers being 22.9(6) and 153.9(5) K, respectively. They are typical SIM examples with their performances tuned by the coordination geometries of metal ions.