具有立体元素的分子电机的全光化学旋转
Gregory B Boursalian1, Eise R Nijboer1, Ruth Dorel1
1Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Journal of the American Chemical Society
|September 9, 2020
概括
新的分子电机实现全光化学单向旋转,这是一个罕见的壮举. 它们独特的中心使得第一个全360度分子电机旋转周期的晶体学特征成为可能.
科学领域:
- 有机化学
- 超分子化学
- 摄影化学
背景情况:
- 单向分子旋转通常依赖于组合的光化学和热步骤.
- 分子电机中的纯光化学旋转周期并不常见.
- 过度拥挤的是分子电机设计中的常见动机.
研究的目的:
- 开发能够完全光化学单向旋转的新型第二代分子电机.
- 调查立体中心对分子运动行为的影响.
- 为了实现分子电机的完整旋转周期的晶体学特征.
主要方法:
- 三个新的二代分子电机与中心的合成.
- 分析旋转行为的光化学异构研究.
- 动力分析和计算建模以阐明机制.
- 用X射线结晶学来确定所有二聚体状态的结构.
主要成果:
- 新的分子电机显示出完全光化学的单向旋转.
- 所有四种二聚体状态都通过光化学手段相互转换.
- 获得了所有二聚体状态的第一个X射线晶体结构,用于过度拥挤的基电机的360°旋转.
- 立体中心的热反转为旋转周期提供了捷径.
结论:
- 开发的分子电机在实现纯光化学旋转周期方面取得了重大进展.
- 立体中心引入了独特的轴向性,并使新的机械路径成为可能.
- 结晶学洞察力为分子运动提供了前所未有的原子层次理解.
- 热化为控制分子运动功能提供了一种新的策略.
相关概念视频
ATP Synthase: Mechanism
16.2K
In animals, the mitochondrial F1F0 ATP synthase is the key protein that synthesizes ATP molecules through a complex catalytic mechanism. While the nuclear genome encodes the majority of ATP synthase subunits, the mitochondrial genome encodes some of the enzyme's most critical components. The formation of this multi-subunit enzyme is a complex multi-step process regulated at the level of transcription, translation, and assembly. Defects in one or more of these steps can result in decreased...
16.2K
Photochemical Electrocyclic Reactions: Stereochemistry
2.1K
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
2.1K
Photosystem I
68.9K
Although structurally similar to photosystem II (PSII), photosystem I (PSI) is has a different electron supplier and electron acceptor.
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
68.9K
ATP Driven Pumps I: An Overview
9.5K
ATP-driven pumps, also known as transport ATPases, are integral membrane proteins. They have binding sites for ATP located on the membrane's cytosolic side and the ion-conducting domain in the transmembrane region. These pumps use the free energy released from ATP hydrolysis to move the solutes across cell membranes against an electrochemical gradient.
There are four main types of ATP-driven pumps - P-type, V-type, F-type, and ABC transporter. All these pumps are of varying complexities and...
There are four main types of ATP-driven pumps - P-type, V-type, F-type, and ABC transporter. All these pumps are of varying complexities and...
9.5K
The Photochemical Reaction Center
5.0K
Reaction centers are pigment-protein complexes that initiate energy conversion from photons to chemical entities. Therefore, photochemical reaction center is a more appropriate term that describes these complexes. The Nobel laureates Robert Emerson and William Arnold provided the first experimental evidence of photochemical reaction centers by demonstrating the participation of nearly 2,500 chlorophyll molecules for the release of just one molecule of oxygen. Despite thousands of photosynthetic...
5.0K
ATP Synthase: Structure
14.5K
ATP synthase or ATPase is among the most conserved proteins found in bacteria, mammals, and plants. This enzyme can catalyze a forward reaction in response to the electrochemical gradient, producing ATP from ADP and inorganic phosphate. ATP synthase can also work in a reverse direction by hydrolyzing ATP and generating an electrochemical gradient. Different forms of ATP synthases have evolved special features to meet the specific demands of the cell. Based on their specific feature, ATP...
14.5K


