"イネネ"メタテシスの導入:リング拡張メタテシスのポリメリゼーションは,ノルボネネの高度Cisおよびシンディオタクティックサイクルポリマーにつながる
Soufiane S Nadif1, Tomohiro Kubo2, Stella A Gonsales1
1Center for Catalysis, Department of Chemistry, University of Florida , P.O. Box 117200, Gainesville, Florida 32611, United States.
Journal of the American Chemical Society
|May 13, 2016
まとめ
トングステンアルキリジンはノルボルネンのポリメリゼーションを開始し,周期的なポリノルボルネンを生成する. 複合体3は高度にシスとシンディオタクティックなサイクルポリマーを生産し,高度な特徴付け技術によって確認されています.
科学分野:
- 有機金属化学
- ポリマー科学
- キャタリシス
背景:
- トングステンアルキリジンは有機金属化学における多用途な前駆体である.
- オレフィン転化とポリメリゼーションは,触媒における重要な変換である.
- ポリマーのトポロジーとステレオ化学を制御することは,材料の特性にとって極めて重要です.
研究 の 目的:
- トングステンアルキリジンとエチレンとの反応性を調査する.
- ノルボネンポリメリゼーションにおけるこれらの複合体の触媒的活性を探求する.
- サイクルトポロジーとステレオ選択性に焦点を当てて,結果として生じるポリノルボネン構造を特徴付ける.
主な方法:
- トングステンアルキリジンの合成と特徴付け.
- エチレンと反応して金属サイクロブテンと結合アルキリデン複合体を形成する.
- トングステンアルキリジンをイニシアターとして使用するノルボネンポリメリゼーション
- 固有の粘度,回転半径,エリューション時間を含むポリマーの性質の分析.
主要な成果:
- トングステンアルキリジン (1と3) はエチレンと反応し,金属サイクロブテン (2) と結合アルキリデン (4) を形成する.
- 両方の複合体は,室温でノルボネンポリメリゼーションを開始する.
- 複合体1は非ステレオ選択的ポリマーを生成し,複合体3は高度にシスおよびシンディオタクティックなサイクルポリノルボネンを生成する.
- 合成されたポリノルボネンの周期的トポロジーを確認した.
結論:
- トングステンアルキリジンは,ノルボネンポリメリゼーションの有効なイニシアターとして機能する.
- リガンド環境は,結果のポリノルボネンのステレオ選択性とトポロジーに大きな影響を与える.
- 複合体3は高度にオーダーされたサイクルポリノルボネンへの経路を提供し,先進的な材料での潜在的な応用を提供します.
さらに関連する動画
関連する概念動画
Olefin Metathesis Polymerization: Overview
2.7K
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...
2.7K
Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
3.3K
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...
3.3K
Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)
2.3K
Acyclic diene metathesis polymerization or ADMET polymerization involves cross-metathesis of terminal dienes, such as 1,8-nonadiene, to give linear unsaturated polymer and ethylene. As ADMET is a reversible process, the formed ethylene gas must be removed from the reaction mixture to complete the polymerization process.
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
2.3K
Free-Radical Chain Reaction and Polymerization of Alkenes
10.2K
The conversion of alkenes to macromolecules called polymers is a reaction of high commercial importance. The structure of the polymer is defined by a repeating unit, while the terminal groups are considered insignificant. The average degree of polymerization represents the number of repeating units in the polymer molecule and is denoted by the subscript n.
10.2K
Radical Chain-Growth Polymerization: Chain Branching
2.6K
The skeletal structure of polymers synthesized via radical polymerization is always branched. For example, the polymerization of ethylene by radical polymerization results in a low-density grade of polyethylene with a heavily branched skeletal structure. Here, the radical site abstracts hydrogen from the growing chain, and the radical site shifts from the end (a primary carbon center) to anywhere within the growing chain (a secondary carbon center). Consequently, the part of the chain from the...
2.6K
Ziegler–Natta Chain-Growth Polymerization: Overview
4.2K
Ziegler–Natta polymerization is another form of addition or chain‐growth polymerization used for synthesizing linear polymers over branched polymers. The catalyst used for polymerization is the Ziegler–Natta catalyst, named after Karl Ziegler and Giulio Natta, who developed it in 1953. This catalyst is an organometallic complex of titanium tetrachloride and triethyl aluminum, with the active form of the catalyst being an alkyl titanium compound. Using the Ziegler–Natta...
4.2K


