Strong Axiality in a Dysprosium(III) Bis(borolide) Complex Leads to Magnetic Blocking at 65 K.
Strong Axiality in a Dysprosium(III) Bis(borolide) Complex Leads to Magnetic Blocking at 65 K.
复制标题
DOI：
10.1021/jacs.2c08568
复制
发表时间：
2023-01-25
影响因子：
15
通讯作者：
Whyatt, Yasmin L.
中科院分区：
文献类型：
--
作者：
Long, Jeffrey R.;Chilton, Nicholas F.;Vincent, Alexandre H.;Whyatt, Yasmin L.
[Dy（CpR）2]+型的取代的dysprosocenium配合物在低温下表现出缓慢的磁弛豫，并已成为性能最好的单分子磁体。这些化合物的显着性能部分源于环戊二烯阴离子提供的强轴向配位场，设计具有更强配位场的类似化合物是一种有前途的途径，可以识别在更高温度下保持磁记忆的新单分子磁体。在这里，我们报道了镝双（硼氢化物）化合物[K（18-冠-6）][Dy（BC 4Ph 5）2]（1）的合成和表征，其特征在于镝茂阴离子[Dy（BC 4Ph 5）2]−与两个二阴离子五苯基硼氢化物配体提供的假轴配位环境。可变场磁化数据显示开放的磁滞高达66 K，建立1作为一个性能最好的单分子磁铁之间的dysprosocenium类似物。交流磁化率数据表明，1在高于80 K时通过Orbach机制弛豫，Ueff = 1500（100）cm-1，τ0 = 10-12.0（9）s，而拉曼弛豫和磁化的量子隧穿在较低温度下占主导地位。化合物1表现出65 K的100 s阻断温度，是镝基单分子磁体中报道的最高温度之一。从头算自旋动力学计算支持实验Ueff和τ0值，并使1和两个代表性dysprosocenium阳离子的弛豫动力学的定量比较，产生额外的见解的影响的晶体场分裂和振动耦合上观察到的弛豫行为。重要的是，化合物1代表了开发替代品的一个步骤，以增加轴向取代dysprosocenium单分子磁体。
Substituted dysprosocenium complexes of the type [Dy(CpR)2]+ exhibit slow magnetic relaxation at cryogenic temperatures and have emerged as top-performing single-molecule magnets. The remarkable properties of these compounds derive in part from the strong axial ligand field afforded by the cyclopentadiene anions, and the design of analogous compounds with even stronger ligand fields is one promising route toward identifying new single-molecule magnets that retain a magnetic memory at even higher temperatures. Here, we report the synthesis and characterization of a dysprosium bis(borolide) compound, [K(18-crown-6)][Dy(BC4Ph5)2] (1), featuring the dysprosocenate anion [Dy(BC4Ph5)2]− with a pseudoaxial coordination environment afforded by two dianionic pentaphenyl borolide ligands. Variable-field magnetization data reveal open magnetic hysteresis up to 66 K, establishing 1 as a top-performing single-molecule magnet among its dysprosocenium analogues. Ac magnetic susceptibility data indicate that 1 relaxes via an Orbach mechanism above ∼80 K with Ueff = 1500(100) cm–1 and τ0 = 10–12.0(9) s, whereas Raman relaxation and quantum tunneling of the magnetization dominate at lower temperatures. Compound 1 exhibits a 100 s blocking temperature of 65 K, among the highest reported for dysprosium-based single-molecule magnets. Ab initio spin dynamics calculations support the experimental Ueff and τ0 values and enable a quantitative comparison of the relaxation dynamics of 1 and two representative dysprosocenium cations, yielding additional insights into the impact of the crystal field splitting and vibronic coupling on the observed relaxation behavior. Importantly, compound 1 represents a step toward the development of alternatives to substituted dysprosocenium single-molecule magnets with increased axiality.
登录
查看更多内容
影响因子：
64.8
作者：
Goodwin, Conrad A. P.;Ortu, Fabrizio;Mills, David P.
通讯作者：
Mills, David P.
影响因子：
21.8
作者：
Gaita-Arino, A.;Luis, F.;Coronado, E.
通讯作者：
Coronado, E.
接近分子磁各向异性极限：近乎完美的五角双锥镝(III)单分子磁体
影响因子：
16.6
作者：
Ding, You-Song;Chilton, Nicholas F.;Zheng, Yan-Zhen
通讯作者：
Zheng, Yan-Zhen
影响因子：
--
作者：
ORBACH, R
通讯作者：
ORBACH, R
在不良配位化合物中，Orbach和Raman Spin-lattice松弛的完整视图。
影响因子：
15
作者：
Briganti M;Santanni F;Tesi L;Totti F;Sessoli R;Lunghi A
通讯作者：
Lunghi A