Detailed Analysis of the Crystal Structures and Magnetic Properties of a Dysprosium(III) Phthalocyaninato Sextuple-Decker Complex: Weak f-f Interactions Suppress Magnetic Relaxation.

In the research field of single-molecule magnets (SMMs), lanthanoid-lanthanoid interactions, so-called f-f interactions, are known to affect the SMM properties, although their magnitudes are small. In this article, an SMM with very weak f-f interactions is reported, and the effects of the interactions on the SMM properties are discussed. X-ray structural analysis of the Dy -Cd -phthalocyaninato sextuple-decker complex (Dy Cd ) reveals that the intramolecular Dy-Dy length in Dy Cd is more than 13 Å, which is longer than the intermolecular Dy-Dy length. Even though the two Dy ions are far apart, intermolecular ferromagnetic dipole-dipole interactions are observed in Dy Cd . From detailed analysis of ac magnetic susceptibilities, quantum tunneling of the magnetization (QTM) in Dy Cd is partially suppressed owing to the existence of very weak Dy-Dy interactions. Our results show that even very weak Dy-Dy interactions act as a dipolar bias, suppressing QTM.