Mondal Arpan, Tang Jinkui, Layfield Richard A
Department of Chemistry, School of Life Sciences, University of Sussex, BN1 9RH, Brighton, U.K.
Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Renmin Street 5626, 130022, Changchun, China.
Angew Chem Int Ed Engl. 2025 Feb 10;64(7):e202420207. doi: 10.1002/anie.202420207. Epub 2024 Nov 19.
A new rare-earth reduction system is described in which trivalent yttrium and dysprosium react as though present in their unstable divalent oxidation state. This masked divalent reactivity is achieved using the isocarbonyl-bridged dimers [( M)(μ-Fp)] (M=Y, 1; M=Dy, 1; Cp=1,2,4-C BuH; Fp=CpFe(CO)), where the reducing electrons originate from the bridging [Fp] ligands. The reactivity of 1 and 1 is showcased by reducing the N-heterocycles 2,2'-bipyridyl (bipy), phenazine (phnz) and hexaazatrinaphthylene (HAN) to give corresponding mono-, di- and tri-metallic rare-earth complexes, respectively, with the heterocyclic ligands present in their singly, doubly and triply reduced forms, respectively. The dynamic magnetic properties of the dysprosium compounds are described. Compound 1 is a single-molecule magnet (SMM) with an appreciable energy barrier of 449(17) cm, whereas [( Dy)(μ-phnz)] (3) is not an SMM because of a strong, competing equatorial crystal field. Surprisingly, [( Dy)(HAN)] (4) is also not an SMM, the origins of which are traced to the impact of the tert-butyl substituents on the dysprosium centre and its interaction with the radical [HAN] ligand.
描述了一种新的稀土还原体系，其中三价钇和镝的反应就好像它们以不稳定的二价氧化态存在一样。这种被掩盖的二价反应性是通过使用异羰基桥连二聚体[(M)(μ-Fp)]（M = Y，1；M = Dy，1；Cp = 1,2,4-CBuH；Fp = CpFe(CO)）实现的，其中还原电子源自桥连的[Fp]配体。通过将N-杂环2,2'-联吡啶（bipy）、吩嗪（phnz）和六氮杂三亚萘（HAN）还原，分别得到相应的单金属、双金属和三金属稀土配合物，展示了1和1的反应性，其中杂环配体分别以单还原、双还原和三还原形式存在。描述了镝化合物的动态磁性质。化合物1是一种单分子磁体（SMM），具有449(17) cm的可观能垒，而[(Dy)(μ-phnz)]（3）不是SMM，因为存在强烈的竞争赤道晶体场。令人惊讶的是，[(Dy)(HAN)]（4）也不是SMM，其原因可追溯到叔丁基取代基对镝中心的影响及其与自由基[HAN]配体的相互作用。
