強発光と高性能単イオン磁性を示す多機能性シアノ架橋型錯体の研究

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This year, following the research objective of searching for novel functional luminescent single-molecule magnets (SMMs) based on lanthanide complexes, I have focused on the magnetic and luminescent studies on a cyanido-bridged d-f bimetallic coordination framework built of Tb(III) and hexacyanocobaltate(III). Single crystal structure study unveiled that this framework can bear a topotactic transformation between an as-synthesized hydrated phase, {[Tb(H2O)2][Co(CN)6] 2H2O}0.7H2O, and its dehydrated phase, Tb[Co(CN)6], reversibly induced by room temperature hydration and thermal dehydration. As a consequence, the functional center, Tb(III) ion, exhibits a switchable characteristics on both magnetic and luminescent properties. Upon dehydration, the Tb complex converts into a highly symmetric trigonal prism geometry, which leads to a very large magnetic anisotropy with Orbach energy barrier over ca. 450 cm^(-1). Such high value is comparable to the very historical yet best Tb(III)- phthalocyaninato SMM system, and we proudly introduce a totally new class of high-performance Tb(III)-SMM in this work. In addition, the Tb-centered luminescence intensity and spectral pattern change due to the variation of ligand field, resulting in a modified optical thermometric characteristic. Notably, the working temperature ranges of SMM behavior and the optical thermometry for the dehydrated phase overlap largely between 6 K to 45 K. Such temperature overlap is to-date the widest, and it opened great possibility of real-time temperature monitoring for the functioning center of a SMM.