Akira B. Miura

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.

Fabrication of gold clusters photoreduced in gold-dendrimer complex nanoparticles

Au clusters, embedded in a dendrimer nanoparticle, have been successfully fabricated by photoreduction of gold ion-dendrimer complex nanoparticles that were fabricated using the reprecipitation method. The electron microscope observations suggested that the Au cluster was formed in an individual gold ion-dendrimer complex after 10 min of UV irradiation. As a result, Au clusters with 1.3 ± 0.6 nm were obtained as a minimum size. In addition, the final size of Au clusters can be controlled by changing UV irradiation time through the aggregation (or fusion) of Au clusters and/or Au ions in several dendrimer molecules.