Single-molecule magnets are a type of coordination compound that can retain magnetic information at low temperatures. Single-molecule magnets based on lanthanides have accounted for many important advances, including systems with very large energy barriers to reversal of the magnetization, and a di-terbium complex that displays magnetic hysteresis up to 14 K and shows strong coercivity. Ligand design is crucial for the development of new single-molecule magnets: organometallic chemistry presents possibilities for using unconventional ligands, particularly those with soft donor groups. Here we report dysprosium single-molecule magnets with neutral and anionic phosphorus donor ligands, and show that their properties change dramatically when varying the ligand from phosphine to phosphide to phosphinidene. A phosphide-ligated, trimetallic dysprosium single-molecule magnet relaxes via the second-excited Kramers' doublet, and, when doped into a diamagnetic matrix at the single-ion level, produces a large energy barrier of 256 cm−1 and magnetic hysteresis up to 4.4 K.
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机译:单分子磁体是一种可在低温下保留磁信息的配位化合物。基于镧系元素的单分子磁体已经取得了许多重要的进步,包括对逆磁化具有非常大的能垒的系统,以及显示出高达14 K的磁滞并显示出强大矫顽力的二di复合物。配体设计对于开发新型单分子磁体至关重要:有机金属化学为使用非常规配体(尤其是具有软施主基团的配体)提供了可能性。在这里,我们报告了具有中性和阴离子磷供体配体的single单分子磁体,并显示了当将配体从膦改为磷化物再变为次膦时,它们的性能发生了巨大变化。磷化物结合的三金属单分子磁体通过二次激发的Kramers双峰弛豫,并以单离子水平掺杂到抗磁性基质中时,产生256 cm ,磁滞高达4.4K。
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