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

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.