刺激诱导自组装的2链链和构成协调环之间的可逆切换
Raveena Soni1, Devjanee Bardhan1, Shobhana Krishnaswamy1
1IoE Center of Molecular Architecture, Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India.
Chemistry (Weinheim an der Bergstrasse, Germany)
|November 25, 2024
概括
研究人员开发了一种新方法,可以创建称为catenanes的相互锁定的分子环. 这种方法使用阳离子结合可逆地切换链和它们的单个环组成部分,为新型分子机器铺平了道路.
科学领域:
- 超分子化学 超分子化学
- 协调化学 协调化学
- 材料科学 材料科学 材料科学
背景情况:
- 连锁体是机械互锁的分子架构,具有独特的特性.
- 控制联体的组装和拆卸对于开发分子机器至关重要.
研究的目的:
- 设计和合成使用易于获得的配体和金属离子的新型连锁结构.
- 为了研究客分子在联体的形成和分解中的作用.
- 为了建立一个原则,可逆切换之间的catenanes和它们的组成环.
主要方法:
- 使用 cis-Pd (tmeda) 2+,C 型联结体 L1 和线性联结体 L3 的八联结体 2-catenane 的单合成.
- 在客人的存在下形成客人绑定的协调环. di-anionic客人.
- 与C形联结体L22+和L3复合,形成一个六性巨型单环环.
- 演示受客诱导的环分离和随后的回归到连锁链结构.
主要成果:
- 成功合成了一种八度电离的2-catenane和一个六度电离的宏观单环环.
- 展示了客人诱导的分离,使连成其组成环.
- 通过隔离客分子来证明该过程的可逆性.
- 建立了离子结合和封存作为可逆切换的核心概念.
结论:
- 已经建立了一个新的设计原则,用于可逆切换catenane和macromonocyclic环.
- 阳离子结合和封存为控制超分子组合提供了一种多功能策略.
- 这项工作为开发响应性分子材料和机器提供了基础.
相关概念视频
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
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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.
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01:17Thermal Electrocyclic Reactions: Stereochemistry
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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.
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02:02Chair Conformation of Cyclohexane
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The chair conformation is the most stable form of cyclohexane due to the absence of angle and torsional strain. The absence of angle strain is a result of cyclohexane’s bond angle being very close to the ideal tetrahedral bond angle of 109.5° in its chair conformer. Similarly, the torsional strain is also absent owing to the perfectly staggered arrangement of bonds.
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this...
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this...
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01:21[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement
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The Cope rearrangement is classified as a [3,3] sigmatropic shift in 1,5-dienes, leading to a more stable, isomeric 1,5-diene. The reaction involves a concerted movement of six electrons, four from two π bonds and two from a σ bond, via an energetically favorable chair-like transition state.
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01:26Photochemical Electrocyclic Reactions: Stereochemistry
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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
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02:34Structural Isomerism
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Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
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