Stimuli-responsive pyrimidine ring rotation in copper complexes for switching their physical properties.
Stimuli-responsive pyrimidine ring rotation in copper complexes for switching their physical properties.
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DOI：
10.1039/c3cp44710c
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发表时间：
2013-06
期刊：
影响因子：
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通讯作者：
Michihiro Nishikawa;S. Kume;H. Nishihara
中科院分区：
文献类型：
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作者：
Michihiro Nishikawa;S. Kume;H. Nishihara
本文总结了我们最近的研究结果，发展的人工分子转子系统，表现出在氧化还原电位和光致发光响应于外部刺激，如热和光子的变化。分子转子由带有两个双齿配体的铜配合物组成;转子在这里被描述为[Cu（Rpp）（L（x））]（+），其中Rpp和L（x）分别是4-甲基-2-（2 '-吡啶基）嘧啶衍生物和具有大体积部分x的双齿配体，并且嘧啶环可以在铜中心旁边旋转，同时保持吡啶-铜连接。该系统的简单性使我们能够更精确地设计旋转运动。我们预期在L（x）部分的旋转轨迹中放置一个壁会降低旋转动力学的速率。这种缓慢的旋转速率是实现外部刺激诱导的从平衡到亚稳态的转换的关键因素。这种切换是基于四个稳定的异构体来自旋转和氧化态，其行为的特点是孤立的铜（I）配合物，在几个温度下使用光谱和电化学测量。利用环旋转产生的空间位移不仅表现出良好的氧化触发运动，而且还调制电极的静止电位，操纵分子内电子转移，开发基于光驱动旋转的氧化还原电位开关，并展示双发光行为。
This paper summarizes the results of our recent studies on the development of an artificial molecular rotor system that exhibits a change in redox potential and photoluminescence in response to external stimuli such as heat and photons. The molecular rotor is made of copper complexes bearing two bidentate ligands; the rotor is described here as [Cu(Rpmpy)(L(x))](+), where Rpmpy and L(x) are a 4-methyl-2-(2'-pyridyl)pyrimidine derivative and a bidendate ligand with bulky moieties, x, respectively, and the pyrimidine ring can rotate beside the copper centre while maintaining the pyridine-copper connection. The simplicity of the system enabled us to design the rotating motion more accurately. We expected that placing a wall in the rotational trajectory in the L(x) moiety would decrease the rate of the rotational dynamics. This slow rate of rotation was a key factor in achieving an external-stimuli-induced switching from thr equilibrium to metastable states. This switching was based on four stable isomers derived from the rotation and oxidation states, the behaviours of which were characterized for isolated copper(I) complexes using spectroscopic and electrochemical measurements at several temperatures. The steric shifts arising from the ring rotation were exploited not only to exhibit well-established oxidation-triggered motion but also to modulate the rest potential of the electrode, to manipulate the intramolecular electron transfer, to develop a redox potential switch based on photo-driven rotation, and to demonstrate the dual-luminescence behaviour.