Pfleger Rouven F, Briganti Matteo, Bonde Niels, Ollivier Jacques, Braun Jonas, Bergfeldt Thomas, Piligkos Stergios, Ruppert Thomas, Anson Christopher E, Perfetti Mauro, Bendix Jesper, Powell Annie K
Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131, Karlsruhe, Germany.
Department of Chemistry "U.Schiff", University of Florence, Via della Lastruccia 3-13, Sesto Fiorentino, Italy.
Chemistry. 2024 Oct 7;31(7):e202403002. doi: 10.1002/chem.202403002.
We report the synthesis, structures and magnetic behaviour of two isostructural dinuclear Dy complexes where the metal ions of a previously reported monomeric building block are connected by a peroxide (O ) or a pair of fluoride (2×F) bridges. The nature of the bridge determines the distance between the metal ion dipoles leading to a dipolar coupling in the peroxido bridged compound of only ca. 70 % of that in the bis-fluorido bridged dimer. The sign of the overall coupling between the metals is antiferromagnetic for the peroxido bridged compound and ferromagnetic for the bis-fluorido bridged complex. This in turn influences the magnetisation dynamics. We compare the relaxation characteristics of the dimers with those of the previously reported monomeric building block. The relaxation dynamics for the bis-fluorido system are very fast. On the other hand, comparing the properties of the monomer, the peroxido bridged sample and the corresponding Y-doped sample show that the relaxation properties via a Raman process have very similar parameters. We show that a second dysprosium is important for either tuning or detuning the Single Molecule Magnet (SMM) properties of a system.
我们报道了两种同构双核镝配合物的合成、结构及磁行为，其中先前报道的单体结构单元中的金属离子通过过氧化物（O）或一对氟化物（2×F）桥相连。桥的性质决定了金属离子偶极之间的距离，导致过氧桥联化合物中的偶极耦合仅约为双氟桥联二聚体中的70%。金属间整体耦合的符号对于过氧桥联化合物是反铁磁性的，而对于双氟桥联配合物是铁磁性的。这反过来又影响了磁化动力学。我们将二聚体的弛豫特性与先前报道的单体结构单元的弛豫特性进行了比较。双氟体系的弛豫动力学非常快。另一方面，比较单体、过氧桥联样品和相应钇掺杂样品的性质表明，通过拉曼过程的弛豫性质具有非常相似的参数。我们表明，第二个镝对于调节或失调系统的单分子磁体（SMM）性质很重要。
