Impact of the coordination environment on the magnetic properties of single-molecule magnets based on homo- and hetero-dinuclear terbium(iii) heteroleptic tris(crownphthalocyaninate)†
Abstract
A series of TbIII triple-decker heteroleptic crownphthalocyaninate complexes consisting of a homodinuclear compound [(15C5)4Pc]Tb[(15C5)4Pc]Tb(Pc) (1), and two novel heterodinuclear compounds [(15C5)4Pc]Tb[(15C5)4Pc]Y(Pc), (2) and [(15C5)4Pc]Y[(15C5)4Pc]Tb(Pc) (3), have been synthesized. All compounds were characterised using UV-Vis spectroscopy, HR-ESI-MS, MALDI-TOF-MS, and 1H NMR spectroscopy, followed by exploration into the effects of lanthanide coupling and ligand field symmetry on the magnetic properties of these complexes using SQUID magnetometry. Magnetic measurements on the homonuclear TbIII complex (1) displayed non-negligible ferromagnetic coupling between magnetic ions, eliciting a high zero-field energetic barrier to the magnetic relaxation of Ueff = 229.9(0) K, while the heteronuclear TbIII/YIII complexes displayed single-ion field-induced slow relaxation of the magnetization; yielding energetic barriers of Ueff = 129.8(0) K for 2, and 169.1(8) K for 3.