Tacconi Leonardo, Manvell Anna S, Briganti Matteo, Czernia Dominik, Weihe Høgni, Konieczny Piotr, Bendix Jesper, Perfetti Mauro
Department of Chemistry "Ugo Schiff" & INSTM RU, Università degli Studi di Firenze, Via della Lastruccia 3, 50019, Sesto F.no (FI), Italy.
Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100, Copenhagen, Denmark.
Angew Chem Int Ed Engl. 2025 Jan 27;64(5):e202417582. doi: 10.1002/anie.202417582. Epub 2024 Nov 26.
Three new 3 d-4 f complexes of general formula trans-[MF(py)][LnDOTA] (M=Cr or Co, Ln=Dy or Y, py=pyridine and DOTA=tetraazacyclododecane-N,N',N'',N'''-tetraacetate) have been synthetised. The fluoride-bridged systems were designed to achieve perfect tetragonal symmetry by combining four-fold symmetric lanthanide and transition metal building blocks. From single crystal measurements, an unprecedented switch of the tetragonal anisotropy of the Dy complexes has been observed. A combination of spectroscopic observations, magnetometry measurements and ab initio calculations allowed us to pinpoint the origin of this phenomenon, which is related to the peculiar energy level structure of the complexes. Moreover, the fourfold anisotropy of the complex has been exploited to design a rotating magnetocaloric experiment showing that tetragonal anisotropy holds great potential to engineer a new class of more efficient magnetic refrigerants.
合成了三种通式为反式-[MF(py)][LnDOTA]（M = Cr 或 Co，Ln = Dy 或 Y，py = 吡啶，DOTA = 四氮杂环十二烷-N,N',N'',N'''-四乙酸）的新型 3d-4f 配合物。通过结合具有四重对称性的镧系和过渡金属结构单元，设计出了氟桥连体系，以实现完美的四方对称性。通过单晶测量，观察到 Dy 配合物的四方各向异性出现了前所未有的转变。光谱观测、磁学测量和从头算计算相结合，使我们能够确定这一现象的起源，它与配合物独特的能级结构有关。此外，利用该配合物的四重各向异性设计了一个旋转磁热实验，结果表明四方各向异性在设计一类更高效的新型磁性制冷剂方面具有巨大潜力。
