Bidirectional photomagnetic conversions in a spin-crossover complex with a diarylethene moiety.
Bidirectional photomagnetic conversions in a spin-crossover complex with a diarylethene moiety.
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DOI：
10.1002/chem.201300767
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发表时间：
2013-05
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影响因子：
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通讯作者：
M. Nihei;Yukihide Suzuki;N. Kimura;Yosuke Kera;H. Oshio
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文献类型：
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作者：
M. Nihei;Yukihide Suzuki;N. Kimura;Yosuke Kera;H. Oshio
双稳态材料可以通过光照射在两种独特的状态之间转换，由于其作为未来分子存储器和开关器件组件的潜在应用，引起了持续的研究兴趣。 McGarvey 等人首次在溶液状态下的铁 (II) 自旋交叉 (SCO) 配合物中观察到介于反磁性低自旋 (LS) 和顺磁性亚稳态高自旋 (HS) 状态之间的光切换磁性。[1] Hauser 等人在固态中，[2] 这被称为光诱导激发自旋态捕获 (LIESST)。[3]尽管许多自旋交叉配合物已被证明表现出 LIESST 效应，但 LIESST（亚稳态 HS）态的弛豫温度通常低于约 50 K。 [3, 4] 然而，已经找到了实现具有高温光诱导亚稳态系统的方法。合作的SCO材料[Fe-ACHTUNGTRENNUNG (pyrazine){Pt (CN) 4}]通过高功率脉冲激光照射在室温下表现出光诱导HS态。[5]Roux等人提出了另一种在较高温度下实现光磁效应的方法。 1994年：配体驱动的光诱导自旋变化（LD-LISC）。[6] LDLISC 基于 SCO 复合物与光致变色配体的组合。在光致变色分子中，光照射引起的结构和电子态变化可以改变配体场强，从而导致 HS 和 LS 态之间的自旋态变化。 LD-LISC效应的优点是光诱导的自旋转换可以在较高的温度范围内运行，并且可以通过相对低功率的光源的照射来激发。值得注意的是，LD-LISC 效应已被证明发生在单分子中，甚至在溶液中； LD-LISC 不依赖分子间协同作用来实现自旋转换。然而，尽管有其优点，表现出 LD-LISC 效应的材料数量仍然有限。 [7]
Bistable materials, which can be converted between two unique states by light irradiation, have attracted continuous research interest due to their potential applications as components of future molecular memory and switching devices. Photoswitchable magnetism, between a diamagnetic low spin (LS) and a paramagnetic metastable high spin (HS) state was first observed for iron (II) spin-crossover (SCO) complexes in the solution state by McGarvey et al.[1] and in the solid state by Hauser et al.,[2] and this was called light-induced excited-spin-state trapping (LIESST).[3] Although many spin-crossover complexes have been shown to display the LIESST effect, the relaxation temperatures of the LIESST (metastable HS) states were usually lower than about 50 K.[3, 4] Means were found, however, to realize systems with high-temperature photo-induced metastable states. The cooperative SCO material[Fe-ACHTUNGTRENNUNG (pyrazine){Pt (CN) 4}] showed a photo-induced HS state at room temperature through irradiation with a high-powered pulsed laser.[5]Another approach to achieve photomagnetic effects at higher temperatures was proposed by Roux et al. in 1994: ligand-driven light-induced spin change (LD-LISC).[6] LDLISC is based on the combination of a SCO complex with photochromic ligands. In photochromic molecules, structural and electronic state changes induced by light irradiation can alter the ligand field strength, which can lead to spin-state changes between HS and LS states. The advantage of the LD-LISC effect is that the light-induced spin conversions can operate in higher temperature ranges and can be stimulated by irradiation from relatively low-powered light sources. It should be noted that LD-LISC effects have been shown to occur in single molecules and even in solution; LD-LISC does not rely upon intermolecular cooperativity to enable spin conversion. Despite its benefits however, the number of materials exhibiting the LD-LISC effect is still limited.[7]