アキラルアニオン刺激によるダイナミックヘリシティの逆転が,合成ラビルコバルト ((II) 複合体における
Hiroyuki Miyake1, Kana Yoshida, Hideki Sugimoto
1Department of Chemistry, Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan. miyake@sci.osaka-cu.ac.jp
Journal of the American Chemical Society
|May 27, 2004
まとめ
チラルのコバルト複合体は,その螺旋構造をラムダからデルタに切り替えることができる. この変化は,窒素アニオンを加えることで引き起こされ,分子キラリティに対する外部制御が示されます.
科学分野:
- 協調化化学について
- 超分子化学 超分子化学
- チラリティ研究 チラリティ研究
背景:
- チラル金属複合体は,非対称合成と分子認識において極めて重要です.
- 金属複合体のステレオ化学を制御し,切り替えることは,化学における重要な課題です.
研究 の 目的:
- コバルト (II) 複合体の螺旋性キラリティに対するアキラルアニオンの影響を調査する.
- 協調化合物におけるステレオ化学の外部刺激によるスイッチングを実証する.
主な方法:
- チラルコバルト ((II) 複合体とテトラデント酸リガンドの合成.
- 複雑な構造とキラリティを決定するために,光譜および結晶学的分析を行います.
- アキラル酸ナイトアニオンの添加とキラル性の変化のモニタリング.
主要な成果:
- コバルト (((II) 複合体は螺旋状のキラリティを示しています.
- アキラル酸ナイトアニオンの加わりは,ラムダからデルタへの螺旋的なキラリティを完全に逆転させます.
- アキラル酸ナイトアニオンは,立体化学逆転のための効果的な外部刺激として作用します.
結論:
- コバルト (II) 複合体の螺旋性キラリティは,アキラル外部の刺激によって可逆的に制御することができます.
- この発見は,切り替え可能なキラル材料と触媒の設計に新たな道を開く.
関連する概念動画
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...
Radical Chain-Growth Polymerization: Mechanism
The radical chain-growth polymerization mechanism consists of three steps: initiation, propagation, and termination of polymerization. The polymerization initiates when a free radical generated from the radical initiator adds to the unsaturated bond in the monomer. The unpaired electron of the free radical and one π electron in the unsaturated bond creates a σ bond between the free radical and the monomer. As a result, the other π electron in the unsaturated bond converts this species into the...
Anionic Chain-Growth Polymerization: Overview
The polymerization process that involves carbanion as an intermediate is called anionic polymerization. It is also a type of addition or chain-growth polymerization. Anionic polymerization gets initiated by a strong nucleophile such as an organolithium or a Grignard reagent. The most commonly used initiator for anionic polymerization is butyl lithium. Monomers involved in anionic polymerization must possess a vinyl group bonded to one or two electron-withdrawing groups. For instance,...
Anionic Chain-Growth Polymerization: Mechanism
The mechanism for anionic chain-growth polymerization involves initiation, propagation, and termination steps. In the initiation step, a nucleophilic anion, such as butyl lithium, initiates the polymerization process by attacking the π bond of the vinylic monomer. As a result, a carbanion, stabilized by the electron‐withdrawing group, is generated. The resulting carbanion acts as a Michael donor in the propagation step and attacks the second vinylic monomer, which acts as a Michael acceptor.
Cationic Chain-Growth Polymerization: Mechanism
The cationic polymerization mechanism consists of three steps: initiation, propagation, and termination. In the initiation step of the polymerization process, the π bond of a monomer gets protonated by the Lewis acid catalyst, which is formed from boron trifluoride and water. The protonation of the π bond generates a carbocation stabilized by the electron‐donating group. In the propagation step, the π bond of the second monomer acts as a nucleophile and attacks the generated carbocation,...
Unsymmetric Bending - Angle of Neutral Axis
Unsymmetrical bending occurs when a structural member is subjected to bending moments in a plane that does not align with the member's principal axes. This scenario typically arises in beams and other structural components when loads are applied at non-ideal angles, introducing complexities in stress analysis.
When a bending moment is applied at an angle θ concerning the vertical axis of a symmetrical member, it can be resolved into components along the member's principal centroidal axes. The...
When a bending moment is applied at an angle θ concerning the vertical axis of a symmetrical member, it can be resolved into components along the member's principal centroidal axes. The...


