Department of Chemistry Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8578, Japan.
Present address: Research Center for Structural Thermodynamics, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka, 560-0043, Japan.
Chemistry. 2019 Feb 26;25(12):3098-3104. doi: 10.1002/chem.201805368. Epub 2019 Feb 4.
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.
在单分子磁体（SMM）的研究领域中，已知镧系元素-镧系元素相互作用，即所谓的 f-f 相互作用，会影响 SMM 的性质，尽管它们的大小很小。本文报道了一个具有非常弱的 f-f 相互作用的 SMM，并讨论了相互作用对 SMM 性质的影响。X 射线结构分析表明，Dy-Cd-酞菁六重堆积配合物（DyCd）中的分子内 Dy-Dy 长度超过 13 Å，比分子间 Dy-Dy 长度长。尽管两个 Dy 离子相距很远，但在 DyCd 中观察到了分子间铁磁性偶极子-偶极子相互作用。从交流磁化率的详细分析可知，由于存在非常弱的 Dy-Dy 相互作用，DyCd 中的磁量子隧道效应（QTM）部分受到抑制。我们的结果表明，即使是非常弱的 Dy-Dy 相互作用也会作为偶极子偏置，抑制 QTM。
