Eステレオレギュラー1,1と1,3の構成単位は,高度に阻害されたc(2) の対称メタルロセーンによって触媒化されたコポリメリゼーションにおける1,3-ブタジエンの構成単位である
Pasquale Longo1, Stefania Pragliola, Giuseppe Milano
1Università di Salerno, Dipartimento di Chimica Via S. Allende, I-84081 Baronissi Salerno, Italy.
Journal of the American Chemical Society
|April 17, 2003
まとめ
高度に阻害されたメタルロセンの触媒は,エーテン/ブタジエンの共ポリメリゼーションにおける前例のないE-選択的1.1および1.3構成単位を可能にし,反応機構とステレオ選択性に関する洞察を明らかにします. これは,ポリマー化学の進歩を意味する.
科学分野:
- ポリマー化学のポリマー化学について
- オーガノメタリック触媒.
背景:
- オレフィンとダイエンの共ポリマー化により,構造的およびステレオ化学的結果の制御に課題が生じます.
- メタロセン触媒はオレフィンポリメリゼーションにチューナブルな特性を提供しますが,ダイエンで特定のマイクロ構造を達成することは複雑です.
研究 の 目的:
- エチネ/ブタジエネ共ポリマーのE構成で前例のない1.1と1.3の構成単位を達成する.
- 阻害メタルロセンの触媒を用いたコポリメリゼーションのメカニズムとステレオ選択性を解明する.
主な方法:
- 高い温度と低いエチンの濃度でエチンと1,3-ブタジエンの共ポリマー化.
- 非常に阻害されたC(2) -対称メタルロセンの触媒を使用しました.
- ポリマーの微細構造と反応運動を研究した.
- サイクロプロパネーション反応の分子モデリングを行いました.
主要な成果:
- E構成の1.1と1.3の構成単位で前例のない収量が得られた.
- 標準条件下では,触媒はメチレン-1,2-サイクロプロパン単位を主に形成した.
- 運動分析では,シクロプロパネーションの速度決定のステップにはエテンが関与しているが,1,1/1,3単位形成には関与していないことが示された.
- 分子モデリングは,アルリルイソメリゼーションによるE-ステレオ選択性を支持しました.
結論:
- エチネ/ブタジエンの共ポリメリゼーションにおける特定の構成単位への新しい経路が確立されました.
- この発見は,メタルロケーンで触媒化されたダイエンの組み込みをより深く理解することを可能にします.
- この研究は,イソメリゼーションメカニズムを通じた観察されたE-ステレオ選択性の合理化を提供します.
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