メタル・オーガニック・フレームからポリチオフェンへのキラリティの転写
Takashi Kitao1,2, Yujiro Nagasaka2, Masanobu Karasawa3
1Department of Applied Chemistry, Graduate School of Engineering , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-8656 , Japan.
Journal of the American Chemical Society
|December 3, 2019
まとめ
キラルの金属有機フレームワーク (MOF) は,アキラルのポリチオフェン (PTh) ポリマーにキラリティを与える. この閉じ込めは,MOFのサポートから取り除かれた後でも,PThの安定したキラリティを誘導します.
科学分野:
- 材料科学
- ポリマー化学
- クリスタルグラフィー
背景:
- 化学と生物学の基本的な性質です
- 高度なアプリケーションでは,ポリマーのキラリティを誘導することが重要です.
- メタル・オーガニック・フレームワーク (MOF) は,材料合成のための調整可能なナノ環境を提供します.
研究 の 目的:
- キラルMOFからアキラルポリマーへのキラル性移転を調査する.
- ナノコンフィネメントがポリマーのキラリティに及ぼす影響を調査する.
- キラルポリマーの生成と安定化のための方法を開発する.
主な方法:
- キラルMOFナノチャネル内の非置換ポリチオフェン (PTh) の合成
- カイロプティカルな性質を分析するために,円形の二重化 (CD) スペクトロスコーピーを用いる.
- キラリティの安定性を評価するための熱分析.
主要な成果:
- アキラルPThはキラルMOFに閉じ込められたときにキラル性を獲得した.
- カイロプティカルプロパティは,PThの負荷とアセンブリの厚さを制御することによって調節可能であった.
- MOFのサポートから削除された後でも,PThのチラリティは持続しました.
- 回収されたPThは250 °Cまでの高熱安定性を示した.
結論:
- チラルMOFは,ポリマーのチラリティを誘導し制御するための効果的なプラットフォームを提供します.
- ナノコンフィネンションは 光学的に活性なポリマーを作るための 実行可能な戦略です
- この方法は,ポリマーアセンブリにおける連鎖間および連鎖内キラリティの研究を容易にする.
関連する概念動画
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
2.9K
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.
2.9K
01:17Thermal Electrocyclic Reactions: Stereochemistry
2.4K
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.
2.4K
01:26Polymer Classification: Stereospecificity
3.1K
Polymerization generates chiral centers along the entire backbone of a polymer chain. Accordingly, the stereochemistry of the substituent group has a significant effect on polymer properties. Polymers formed from monosubstituted alkene monomers feature chiral carbons at every alternate position in the polymer backbone. Relative to the predominant orientation of substituents at the adjacent chiral carbons, the polymer can exist in three different configurations: isotactic, syndiotactic, and...
3.1K
01:13Olefin Metathesis Polymerization: Overview
2.5K
Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
2.5K
01:16Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
3.1K
Ring-opening metathesis polymerization or ROMP involves strained cycloalkenes as starting materials. The mechanism of ROMP proceeds by reacting cycloalkene with Grubbs catalyst to give metallacyclobutane intermediate which undergoes a ring-opening reaction to form new carbene. The new carbene reacts with another molecule of cycloalkene. Repetition of these steps leads to the formation of an unsaturated open-chain polymer product. All these steps are reversible, however, relieving the ring...
3.1K
02:05Prochirality
4.8K
The concept of prochirality leads to the nomenclature of the individual faces of a molecule and plays a crucial role in the enantioselective reaction. It is a concept where two or more achiral molecules react to produce chiral products. A typical process is the reaction of an achiral ketone to generate a chiral alcohol. Here, the achiral reactant reacts with an achiral reducing agent, sodium borohydride, to generate an equimolar mixture of the chiral enantiomers of the product. For example, an...
4.8K