Large Spin-Relaxation Barriers for the Low-Symmetry Organolanthanide Complexes [Cp2*Ln(BPh4)] (Cp*=pentamethylcyclopentadienyl; Ln=Tb, Dy)
Large Spin-Relaxation Barriers for the Low-Symmetry Organolanthanide Complexes [Cp2*Ln(BPh4)] (Cp*=pentamethylcyclopentadienyl; Ln=Tb, Dy)
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DOI：
10.1002/chem.201403751
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发表时间：
2014-07-28
影响因子：
4.3
通讯作者：
Long, Jeffrey R.
中科院分区：
文献类型：
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作者：
Demir, Selvan;Zadrozny, Joseph M.;Long, Jeffrey R.
包含一个自旋中心的单分子磁体代表了基于自旋的信息存储的基本尺寸限制。这种应用取决于具有自旋反转实质势垒的分子的实现。镧系元素的轴对称配合物由于其固有的高磁各向异性和低隧道概率而最有希望实现这一点。在此，我们证明，在[Cp-2*Ln(BPh4)]类型的低对称性镧系元素四苯基硼酸盐配合物中也可以实现216和331 cm(-1)的惊人大的自旋反转势垒（Cp*=五甲基环戊二烯基；Ln=Tb（1）和Dy（2））。镝同系物显示高达 5.3 K 的磁滞磁化数据。对 1 和 2 在施加直流场下以及在 [Cp-2*Y(BPh4)] 矩阵内稀释时的磁弛豫过程的进一步研究揭示了对隧道路径的显着抑制，强调了偶极相互作用对这些系统中低温磁化动力学的强烈影响。
Single-molecule magnets comprising one spin center represent a fundamental size limit for spin-based information storage. Such an application hinges upon the realization of molecules possessing substantial barriers to spin inversion. Axially symmetric complexes of lanthanides hold the most promise for this due to their inherently high magnetic anisotropies and low tunneling probabilities. Herein, we demonstrate that strikingly large spin reversal barriers of 216 and 331 cm(-1) can also be realized in low-symmetry lanthanide tetraphenylborate complexes of the type [Cp-2*Ln(BPh4)] (Cp*=pentamethylcyclopentadienyl; Ln=Tb (1) and Dy (2)). The dysprosium congener showed hysteretic magnetization data up to 5.3 K. Further studies of the magnetic relaxation processes of 1 and 2 under applied dc fields and upon dilution within a matrix of [Cp-2*Y(BPh4)] revealed considerable suppression of the tunneling pathway, emphasizing the strong influence of dipolar interactions on the low-temperature magnetization dynamics in these systems.