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Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)01:16

Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)

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...
Olefin Metathesis Polymerization: Overview01:13

Olefin Metathesis Polymerization: Overview

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...
Radical Chain-Growth Polymerization: Overview01:10

Radical Chain-Growth Polymerization: Overview

Chain-growth or addition polymerization is successive addition reactions of monomers with a polymer chain. In radical chain-growth polymerization, the reaction proceeds via a free-radical intermediate. The free radical is formed from radical initiators, which spontaneously generate free radicals by homolytic fission. Organic peroxides (such as dibenzoyl peroxide, as shown in Figure 1) or azo compounds are popular radical initiators. A low concentration ratio of radical initiator to monomer is...
Acid-Catalyzed Ring-Opening of Epoxides02:24

Acid-Catalyzed Ring-Opening of Epoxides

Epoxides that are three-membered ring systems are more reactive than other cyclic and acyclic ethers. The high reactivity of epoxides originates from the strain present in the ring. This ring strain acts as a driving force for epoxides to undergo ring-opening reactions either with halogen acids or weak nucleophiles in the presence of mild acid. The acid catalyst converts the epoxide oxygen, a poor leaving group, into an oxonium ion, a better leaving group, making the reaction feasible. The...
Base-Catalyzed Ring-Opening of Epoxides02:26

Base-Catalyzed Ring-Opening of Epoxides

Due to their highly strained structures, epoxides can readily undergo ring-opening reactions through nucleophilic substitution, either in the presence of an acid or a base. The nucleophilic substitution reactions in the presence of acid are called acid-catalyzed ring-opening reactions, and nucleophilic substitution reactions in the presence of a base are called base-catalyzed ring-opening reactions. Epoxides undergo base-catalyzed ring-opening reactions in the presence of a strong nucleophile...
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH301:11

ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3

All ortho–para directors, excluding halogens, are activating groups. These groups donate electrons to the ring, making the ring carbons electron-rich. Consequently, the reactivity of the aromatic ring towards electrophilic substitution increases. For instance, the nitration of anisole is about 10,000 times faster than the nitration of benzene. The electron-donating effect of the methoxy group in anisole activates the ortho and para positions on the ring and stabilizes the corresponding...

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関連する実験動画

Updated: Jun 1, 2026

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes
05:48

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes

Published on: November 21, 2017

リング開きポリメリゼーション触媒のレドックス制御

Erin M Broderick1, Neng Guo, Carola S Vogel

  • 1Department of Chemistry & Biochemistry, University of California, Los Angeles, California 90095, USA.

Journal of the American Chemical Society
|May 25, 2011
PubMed
まとめ
この要約は機械生成です。

イットリウムおよびインジウムアルコキシド複合体のレドックス制御は,ポリメリゼーションの速度を調節します. この金属に依存する活動により,ポリマー合成,特にL-ラクチドおよびトリメチレン炭酸の新戦略が生まれます.

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Atom Transfer Radical Polymerization of Functionalized Vinyl Monomers Using Perylene as a Visible Light Photocatalyst
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Atom Transfer Radical Polymerization of Functionalized Vinyl Monomers Using Perylene as a Visible Light Photocatalyst

Published on: April 22, 2016

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers
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Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers

Published on: December 16, 2022

関連する実験動画

Last Updated: Jun 1, 2026

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes
05:48

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes

Published on: November 21, 2017

Atom Transfer Radical Polymerization of Functionalized Vinyl Monomers Using Perylene as a Visible Light Photocatalyst
06:49

Atom Transfer Radical Polymerization of Functionalized Vinyl Monomers Using Perylene as a Visible Light Photocatalyst

Published on: April 22, 2016

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers
08:12

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers

Published on: December 16, 2022

科学分野:

  • 有機金属化学 有機金属化学
  • ポリマーサイエンスの科学
  • カタリシス カタリシス カタリシス

背景:

  • 環開きポリメリゼーション (ROP) は,生物分解性ポリマーの合成に不可欠です.
  • レドックス変化のような外部刺激を通して触媒の活性を制御することは,活発な研究分野です.
  • フェロゼン基リガンドは,金属複合体に対してユニークな酸化還元特性を提供します.

研究 の 目的:

  • ROPにおけるイットリウムおよびインジウムアルコキシド複合体の酸化還元制御を調査する.
  • ポリメリゼーション行動に対する金属同一性の影響を調査する.
  • L-ラクチドとトリメチレン炭酸から派生したポリマーを合成し,特徴づけること.

主な方法:

  • フェロセンのリガンドによるイトリウムアルコキシド複合体の合成と特徴付け.
  • 化学反応剤を用いたイットリウム複合体のレドックス操作.
  • X線結晶学,NMR,XANES,Mössbauerスペクトロスコピーを用いて特徴を決定する.
  • L-ラクチドとトリメチレン炭酸のリング開きポリメリゼーション.
  • ポリマー分析のためのゲル浸透クロマトグラフィ.

主要な成果:

  • イットリウム複合体のポリメリゼーション速度は,酸化還元状態の変化によって調節された.
  • イットリウム複合体の酸化および還元された形態は,異なる触媒的活性を示した.
  • インジウムアルコキシド複合体はイットリウムと比較して逆の行動を示した.
  • ポリメリゼーション率に対する金属ベースの明確な依存性が観察されました.

結論:

  • レドックス交換可能なイトリウムおよびインジウムアルコキシド複合体は,ポリメリゼーション速度を制御することができます.
  • 観測された金属依存的行動は,触媒活動における金属中心の重要性を強調しています.
  • この研究は,制御されたポリマー合成のためのリドックス反応性触媒の設計に関する洞察を提供します.