Effect of f-f interactions on quantum tunnelling of the magnetization: Mono- and dinuclear Dy(iii) phthalocyaninato triple-decker single-molecule magnets with the same octacoordination environment

The single-molecule magnet (SMM) behaviour of dinuclear Ln(iii)-Pc triple-decker complexes (Dy(iii)-Y(iii): 1 and Dy(iii)-Dy(iii): 2) with the same octacoordination environment and slow magnetic relaxation behaviour were explained using X-ray crystallography and static and dynamic susceptibility measurements. In particular, interactions among the 4f electrons of dinuclear Dy(iii)-Pc triple-decker type SMMs have never been discussed on the basis of the same octacoordination environment. Our results clearly show that the Dy(iii) ion sites of 1 and 2 are equivalent, consistent with the crystal structure. 2 Exhibited ferromagnetic interaction between Dy(iii) ions. This is clear evidence that the magnetic relaxation mechanism depends heavily on the dipole-dipole (f-f) interactions between the Dy(iii) ions in the dinuclear systems. For both 1 and 2, quantum tunnelling of the magnetization (QTM) was observed. However, the magnetic relaxation time (τ) for 2 was one order of magnitude greater than that for 1, and single-component magnetic relaxation behaviour was explained. In other words, it is possible to use f-f interactions to increase τ by one order of magnitude. This journal is