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関連する概念動画

Preparation of Epoxides03:00

Preparation of Epoxides

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 peroxy acids to...
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...
Polymer Classification: Stereospecificity01:26

Polymer Classification: Stereospecificity

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...
Structure and Nomenclature of Ethers02:28

Structure and Nomenclature of Ethers

Structure and Bonding
Ethers are organic compounds with an ether functional group which is characterized by an oxygen atom connected to two — identical or different — alkyl, aryl, or vinyl groups. The C–O–C linkage in dimethyl ether — the simplest ether — has an approximately tetrahedral bond angle of 110.3 degrees. The oxygen atom is sp3- hybridized, with the C–O distance being about 140 pm.
Classification of Ethers
Based on their attached substituent groups, ethers can be classified into two...
Structure and Nomenclature of Alcohols and Phenols02:23

Structure and Nomenclature of Alcohols and Phenols

Overview
Alcohols are one of the most important functional groups in organic chemistry. The name of alcohol comes from the hydrocarbon from which it is derived. Alcohols are organic molecules containing the functional hydroxyl or –OH group directly bonded to carbon. Phenols have an OH group directly attached to a benzene ring. While alcohols are colorless, phenol is a white crystalline compound with a characteristic "hospital smell" odor.
As with other organic compounds, alcohols and phenols...
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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Updated: Jun 14, 2026

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

オレフィンポリメリゼーションのためのステレオ特異的八面体群4 bis (((フェノラート)) エーテル複合体.

Elizabeth T Kiesewetter1, Sören Randoll, Madalyn Radlauer

  • 1Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA.

Journal of the American Chemical Society
|April 3, 2010
PubMed
まとめ

ハフニウムとジルコニウムビスフェノ酸エーテル複合体は,高度に活性なアルファ-オレフィンポリメリゼーション触媒である. ハフニウム触媒は優れたステレオ選択性を発揮し,特定の構造特性を有する高品質のポリプロピレンを生成します.

さらに関連する動画

Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of &#945;-Imino &#947;-Lactones and Alkylidene Pyrazolones
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Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones

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

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関連する実験動画

Last Updated: Jun 14, 2026

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

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers

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Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of &#945;-Imino &#947;-Lactones and Alkylidene Pyrazolones
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Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones

Published on: February 7, 2019

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

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:

  • 八面体グループ4のビスフェノラートエーテル複合体は,アルファ-オレフィンポリメリゼーションの触媒として知られています.
  • メチラルミノキサン (MAO) は,これらのタイプの触媒の一般的な活性化剤です.

研究 の 目的:

  • グループ4ビスフェノラートエーテル複合体の触媒活性とステレオ特異性を調査する.
  • ハフニウム (Hf) とジルコニウム (Zr) ベースの触媒の性能を比較する.
  • 触媒のステレオ選択性に対するリガンド構造の影響を理解する.

主な方法:

  • 八面体群4のビスフェノラートエーテル複合体の合成と特徴付け.
  • メチルアルミノキサン (MAO) による複合体の活性化.
  • 構造的な類似点と違いを特定するためのX線結晶分析.
  • 触媒活性とステレオ特異性を評価するためのアルファ-オレフィンポリメリゼーション研究.

主要な成果:

  • ZrとHf複合体は,MAOによって活性化されると,アルファ-オレフィンポリメリゼーションにおいて高い活性とステレオ特異性を示した.
  • X線結晶学では,ZrおよびHf複合体は同構造であり,Hf複合体の結合長がわずかに短くなることが示されました.
  • Hf複合体は,構造的類似性にもかかわらず,Zr複合体と比較して,よりステレオ選択的触媒を生成しました.
  • ビス-テルト-ブチルフェニル置換のHfおよびZr複合体は,高分子量ポリプロピレン (>97%イソタクシー,融点165°Cまで) を生成した.

結論:

  • MAOによって活性化されたグループ4ビスフェノラートエーテル複合体は,アルファ-オレフィンポリメリゼーションの有効でステレオ特異的な触媒である.
  • ハフニウムベースの触媒は,ジルコニウムベースの触媒よりもステレオ選択性が向上しています.
  • リガンド構造は,これらのポリメリゼーション触媒のステレオ特異性を決定する上で重要な役割を果たします.