一种二甲共晶,可以将光转化为机械工作
Masakazu Morimoto1, Masahiro Irie
1Department of Chemistry and Research Center for Smart Molecules, Rikkyo University, Nishi-Ikebukuro 3-34-1, Toshima-ku, Tokyo 171-8501, Japan.
Journal of the American Chemical Society
|September 23, 2010
概括
这项研究显示了一种光色共晶体,在紫外线和可见光下可逆曲. 这些分子晶体可以举起沉重的物体,产生显著的机械应力.
科学领域:
- 材料科学 材料科学 材料科学
- 晶体学 晶体学是指结晶学.
- 摄影化学的使用.
背景情况:
- 光色材料在暴露于光线时会改变颜色.
- 分子晶体具有独特的机械性能.
- 利乙烯衍生物以其光色行为而闻名.
研究的目的:
- 为了研究一种新型的二甲-甲合晶的光机械效应.
- 描述可逆曲运动及其基本机制.
- 探索这种材料在分子执行器中的潜在应用.
主要方法:
- 合成和表征的1,2-bis(2-甲基-5-(1-纳) -3-乙烯) perfluorocyclopentene (1o) 和 perfluoronaphthalene (FN) 的共晶.
- 在现场进行X射线晶体分析以研究晶体变形.
- 分子晶体支柱的机械测试.
- 低温动态测量曲运动.
主要成果:
- 1o·FN共晶体在交替的紫外线和可见光辐射下呈现可逆曲,可重复超过250个周期.
- 晶体变形归因于二甲光环化引起的b轴延长.
- 曲运动即使在4.7K时也会发生,在微秒时间尺度上有异性膨胀.
- 分子晶体支架可以举起重量200-600倍的物体.
- 生成的应力达到44MPa,相当于压电材料.
结论:
- 迪亚利乙烯- perfluoronaphthalene 共同晶体表现出显著的光机械性能.
- 该材料表现出高效且可重复的光感应曲和机械工作.
- 这项研究为开发先进的分子机器和执行器开辟了道路.
相关概念视频
01:26Photochemical Electrocyclic Reactions: Stereochemistry
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
01:17Thermal Electrocyclic Reactions: Stereochemistry
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
01:29Determination of Crystal Structures
In the late 1800s, the revelation that light extended beyond visible wavelengths led to the discovery of X-rays by Wilhelm Roentgen. Recognized as high-energy electromagnetic radiation with short wavelengths, X-rays prompted exploration into their interaction with crystals. Max von Laue proposed in 1912 that the periodic arrangement of atoms, ions, or molecules in crystals would cause them to diffract X-rays, a hypothesis confirmed through experiments with copper sulfate and zinc sulfide...
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01:16[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.
01:35Light as Energy
The energy required to carry out photosynthesis is light— typically electromagnetic radiation from the sun. The range of all possible wavelengths is known as the electromagnetic spectrum.
Photons
A photon is a discrete electromagnetic particle or bundle of energy. Photons are characterized by their frequency, wavelength, and amplitude, similar to the properties of a wave. Waves with higher frequencies transmit more energy and have shorter wavelengths than longer wavelengths that transmit less...
Photons
A photon is a discrete electromagnetic particle or bundle of energy. Photons are characterized by their frequency, wavelength, and amplitude, similar to the properties of a wave. Waves with higher frequencies transmit more energy and have shorter wavelengths than longer wavelengths that transmit less...