エチレン酸化物の螺旋構造の探索: ステリックおよび関連効果を超えて
1Department of Chemistry, Institute of Natural Sciences, Federal University of Lavras, Lavras, MG, 37200-900, Brazil.
まとめ
ダイメトキシエタン (DME) はジグザグ構造を好み,様々な形をとるが,極性溶媒では螺旋形を形成する. この螺旋構造は 安定した複合体を形成する カリウムのようなイオンを 効率的に封じ込めます
科学分野:
- ポリマー科学
- コンピュータ化学
- 材料科学
背景:
- ディメトキシエタン (DME) はポリエチレン酸化物の主要なモノマーであり,材料科学において重要な応用があるポリマーである.
- DMEの形状特性は,イオンとの相互作用に影響を与え,ポリマーの特性に影響を与えます.
- DMEの構造と性質の関係を理解することは,高度な材料の設計に不可欠です.
研究 の 目的:
- 量子化学的方法を用いて,ダイメトキシエタン (DME) の回転性イソメリゼーションと形状的偏好を調査する.
- 特に極性溶媒におけるDMEの螺旋構造形成を制御する要因を解明する.
- カチオンを封じ込むためのDMEオリゴマーの可能性を探求する.
主な方法:
- DMEの9つの回転器を研究するために,量子化学的な計算が採用されました.
- ジグザグやゴーシェの配置を含む形状の好みの分析.
- 溶媒 (例えば,DMSO) がDMEの形状に及ぼす影響を調査する.
- カリウムカチオンと相互作用する21重原子のDMEオリゴマーの研究.
主要な成果:
- DMEは,ジグザグ (オールトランス) の形状を好んで,9つのロタマーを展示し,その後にガウチOCCOの配置があります.
- ジグザグの形状の好みは 鎖の長さを増すにつれて強まります
- 極性溶媒では,二極性排斥が減少し,超結合相互作用が強化されるため,螺旋構造が生じます.
- 21重原子のDMEオリゴーマーが,その螺旋構造をカリウムカチオンに圧縮することで安定した複合体を形成する.
結論:
- DMEの形状は鎖の長さや溶媒の極性に対して敏感であり,極性媒体の螺旋構造を好みます.
- 螺旋構造の形成は,ステリック効果ではなく,電子的要因 (二極反発,超結合) によって引き起こされる.
- DMEオリゴーマーには選択的イオン封じ込みの可能性があり,高度に安定した複合体となる.
さらに関連する動画
09:35Preparation of a Corannulene-functionalized Hexahelicene by CopperI-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
11.6K
08:25Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks MOFs
Published on: January 17, 2020
7.4K
関連する概念動画
01:17Thermal Electrocyclic Reactions: Stereochemistry
2.1K
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.
2.1K
02:18Conformations of Ethane and Propane
14.5K
In an organic molecule, free rotation about the carbon-carbon single bond results in energetically different conformers of the molecule. Due to this rotation, called the internal rotation, ethane has two major conformations — staggered and eclipsed.
Staggered conformation is a low energy and more stable conformation with the C-H bonds on the front carbon placed at 60°dihedral angles relative to the C-H bonds on the back carbon, leading to a reduced torsional strain. In staggered...
Staggered conformation is a low energy and more stable conformation with the C-H bonds on the front carbon placed at 60°dihedral angles relative to the C-H bonds on the back carbon, leading to a reduced torsional strain. In staggered...
14.5K
01:10Radical Reactivity: Steric Effects
2.0K
The presence of electron-donating, electron-withdrawing, or conjugating groups adjacent to a radical center, imparts electronic stabilization to the radicals. Examples of such electronically-stabilized radicals are triphenylmethyl, tetramethylpiperidine‐N‐oxide, and 2,2‐diphenyl‐1‐picrylhydrazyl. These radicals are remarkably stable and are known as persistent radicals. Some of the persistent radicals can even be isolated and purified.
Along with electronic...
Along with electronic...
2.0K
01:12Cycloaddition Reactions: MO Requirements for Photochemical Activation
2.2K
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
2.2K
01:18Directing and Steric Effects in Disubstituted Benzene Derivatives
3.2K
When disubstituted benzenes undergo electrophilic substitution, the product distribution depends on the directing effect of both substituents. When the directing effects of both substituents reinforce each other, a single product is obtained. For example, bromination of p-nitrotoluene occurs ortho to the methyl group and meta to the nitro group, which is the same position, resulting in a single product. However, if the directing effects of the two groups oppose each other, the...
3.2K
03:00Preparation of Epoxides
8.1K
Overview
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of...
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of...
8.1K