Chiral molecular motors driven by a nonhelical laser pulse.
Chiral molecular motors driven by a nonhelical laser pulse.
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由非螺旋激光脉冲驱动的手性分子马达。
DOI：
10.1002/anie.200250872
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发表时间：
2003
影响因子：
--
通讯作者：
Y. Fujimura
中科院分区：
文献类型：
--
作者：
K. Hoki;M. Yamaki;Y. Fujimura
分子发动机和机械领域是应用化学中发展最快的研究领域之一。[1-4]预计这一领域将在纳米科学和纳米技术的出现中发挥重要作用。迄今为止报道的大多数分子马达都是由具有不对称势的手性分子制成的。此外，这些马达由浓度梯度驱动，浓度梯度由热和化学力或电磁辐射的时间相关力产生。[5-9]光驱动的分子马达是特别有趣的，因为它们的旋转方向，以及它们的扭矩，可以通过利用光的性质，如光子偏振，频率和脉冲形状来控制。[10例如，在经典分子动力学的基础上，已经从理论上研究了由圆极化电场驱动的网格安装的分子偶极转子。[6]应该注意的是，如果使用螺旋光场，例如圆偏振激光器，则分子马达的手性是不必要的。[12]关于非螺旋光驱动的手性分子马达的有趣实验最近有报道;[8，9]这种马达由具有两个手性中心的烯烃组成。由线性偏振可见光或UV光诱导的顺反异构化产生围绕中心碳-碳双键的重复单向旋转，随后是热诱导的顺反异构化;后者阻止反向旋转。在这些实验中，马达作用的速率决定步骤是热控制异构化，这是一个不相干的过程。[8，9]据我们所知，只有少数报道使用辐射场的相干特性驱动分子马达。因此，研究由电磁场的相干特性驱动的分子马达是十分必要的。本文在量子力学和经典力学计算的基础上，解释了非螺旋相干光脉冲如何单向驱动手性分子马达。为此，选择了2-氯-5-甲基环戊-2，4-二烯甲醛（图1），这是一种简单的手性分子马达。在本文中，具有R构型的手性分子被称为（R）-
The field of molecular motors and machines is one of the most rapidly advancing research areas in applied chemistry.[1–4] It is expected that this area will play an important role in the advent of nanoscience and nanotechnology. Most of the molecular motors reported to date have been made from chiral molecules that have asymmetric potentials. Furthermore, these motors are driven by concentration gradients that are created by thermal and chemical forces, or by the timecorrelated forces of electromagnetic radiation.[5–9] Lightdriven molecular motors are particularly interesting because their rotational directions, as well as their torque, can be controlled by utilizing the properties of light, such as photon polarization, frequency, and pulse shape.[10, 11] For example, a grid-mounted molecular dipolar rotor, driven by a circularly polarized electric field, has been theoretically studied on the basis of classical molecular dynamics.[6] It should be noted that if helical light fields, such as circularly polarized lasers are used, the chirality of the molecular motors is unnecessary.[12] Interesting experiments regarding nonhelical-light-driven chiral molecular motors have recently been reported;[8, 9] such motors consist of an alkene with two chiral centers. cis–trans Isomerization that is induced by linearly polarized visible or UV light generates repetitive unidirectional rotation around a central carbon–carbon double bond, which is followed by thermally induced cis–trans isomerization; the latter blocks reverse rotation. In those experiments, the ratedetermining step of the motor action is the thermally controlled isomerization, which is an incoherent process.[8, 9] To the best of our knowledge, there are only a few reports on molecular motors driven by using the coherent properties of radiation fields. Investigation of molecular motors driven by the coherent properties of electromagnetic fields is therefore required.In this communication, on the basis of both quantum and classical mechanical calculations, we explain how a chiral molecular motor is unidirectionally driven by a nonhelical coherent light pulse. For this purpose, 2-chloro-5-methylcyclopenta-2, 4-dienecarbaldehyde was chosen (Figure1), which is a simple, chiral molecular motor. In this communication, chiral molecules with an R formation are called (R)-