四嗪基自由基桥联茂金属中的强磁耦合和单分子磁体行为
Strong Magnetic Coupling and Single-Molecule Magnet Behavior in Tetrazinyl Radical-Bridged Metallocenes.
作者信息
Bajaj Neha, Mavragani Niki, Kitos Alexandros A, Gayfullina Rezeda, Moilanen Jani O, Murugesu Muralee
机构信息
Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada.
Department of Chemistry, Nanoscience Centre, University of Jyväskyla, P.O. Box 35, Jyväskyla, FI-40014, Finland.
出版信息
Chemistry. 2025 Jul 17;31(40):e202501542. doi: 10.1002/chem.202501542. Epub 2025 Jul 1.
Exchange coupling is essential in defining the magnetic behavior of polymetallic lanthanide-based (Ln) single-molecule magnets (SMMs), where, thanks to the unpaired electron(s), radical ligands show promise as magnetic bridges between the paramagnetic metal centers. Combining high-performance lanthanide metallocene [Cp₂Ln] (Cp = pentamethylcyclopentadienyl) units with the 3,6-bis(2-pyrimidyl)-1,2,4,5-tetrazine radical ligand (bmtz) yielded two new radical-bridged dinuclear lanthanide metallocenes, (Cp*₂Ln)₂(bmtz)·Solvent (Ln = Gd (1), Solvent = THF; Dy (2), Solvent = toluene). The strong magnetic exchange coupling of J = -12.6 cm observed in 1, was probed via SQUID magnetometry as well as computational studies. This, combined with the highly anisotropic Dy ions in 2, leads to zero-field SMM behavior and slow magnetic relaxation through thermally activated processes.
交换耦合对于定义多金属镧系元素基（Ln）单分子磁体（SMM）的磁行为至关重要，在这种情况下，由于未成对电子，自由基配体有望作为顺磁性金属中心之间的磁桥。将高性能镧系茂金属[Cp₂Ln]（Cp = 五甲基环戊二烯基）单元与3,6-双（2-嘧啶基）-1,2,4,5-四嗪自由基配体（bmtz）结合，得到了两种新的自由基桥联双核镧系茂金属，(Cp*₂Ln)₂(bmtz)·溶剂（Ln = Gd (1)，溶剂 = THF；Dy (2)，溶剂 = 甲苯）。通过超导量子干涉仪磁强计以及计算研究探测到在1中观察到的J = -12.6 cm的强磁交换耦合。这与2中高度各向异性的Dy离子相结合，导致零场SMM行为以及通过热激活过程的慢磁弛豫。
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