Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden, Germany.
Physik-Institut der Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
Nat Commun. 2017 Jul 14;8:16098. doi: 10.1038/ncomms16098.
Increasing the temperature at which molecules behave as single-molecule magnets is a serious challenge in molecular magnetism. One of the ways to address this problem is to create the molecules with strongly coupled lanthanide ions. In this work, endohedral metallofullerenes Y@C and Dy@C are obtained in the form of air-stable benzyl monoadducts. Both feature an unpaired electron trapped between metal ions, thus forming a single-electron metal-metal bond. Giant exchange interactions between lanthanide ions and the unpaired electron result in single-molecule magnetism of Dy@C(CHPh) with a record-high 100 s blocking temperature of 18 K. All magnetic moments in Dy@C(CHPh) are parallel and couple ferromagnetically to form a single spin unit of 21 μ with a dysprosium-electron exchange constant of 32 cm. The barrier of the magnetization reversal of 613 K is assigned to the state in which the spin of one Dy centre is flipped.
提高分子作为单分子磁体的行为温度是分子磁性中的一个重大挑战。解决这个问题的方法之一是创建具有强耦合镧系离子的分子。在这项工作中，富勒烯 Y@C 和 Dy@C 以稳定的苄基单加成物的形式获得。两者都具有被困在金属离子之间的未配对电子，从而形成单电子金属-金属键。镧系离子和未配对电子之间的巨大交换相互作用导致 Dy@C(CHPh) 具有创纪录的 100 s 阻塞温度 18 K 的单分子磁体特性。Dy@C(CHPh) 中的所有磁矩都是平行的，并且铁磁耦合形成一个单自旋单元，具有 21 μ 的磁矩和 32 cm 的镝-电子交换常数。磁化反转的能垒为 613 K，归因于一个 Dy 中心的自旋翻转状态。
