表面トポケミアによるビシェリケーンへのダイアステロセレクティブ・ウルマン結合
Anaïs Mairena1, Christian Wäckerlin1, Martin Wienke2
1Empa, Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf , Switzerland.
Journal of the American Chemical Society
|November 2, 2018
まとめ
黄金の表面に9,9′-ビシェプタエリケンの自己組み立ては,メソフォームの50%のダイアステレオメア余剰を生成する. このステレオ選択性は,表面合成中に表面誘発のトポケミカル効果から生じる.
科学分野:
- 有機化学
- 表面科学
- 超分子化学
背景:
- ヘリケンは独特の構造と電子特性を有するキラル型多環芳香炭化水素である.
- 表面合成は 制御された構造を持つ複雑な有機分子を 構築するための強力なプラットフォームを提供します
- 機能的なナノ材料の設計には 自己組み立てプロセスを理解することが重要です
研究 の 目的:
- 9,9′-ビシェプタヘリセンの自己組み立て行動を,Au(111) 表面で調査する.
- 同じ分子の表面合成と自己組み立て結果を比較する.
- これらのプロセスにおけるステレオ選択性を支配する要因を解明する.
主な方法:
- スキャントンネル顕微鏡 (STM) を用いて,9,9′-ビシェプタヘリケンの自己組立をAu111で研究した.
- 9-ブロモヘプタヘリセンのウールマン結合による表面合成が標的分子を得るために実施された.
- STM画像の分析により,ダイアステレオメアの比率を決定することができました.
主要な成果:
- 9,9′-ビシェプタヘリケンのAu(111) 上の自己組み立ては, (M,P) メソフォームの50%のダイアステロエーマー過剰 (de) を引き起こした.
- 表面合成でも同じダイアステロエーマー過剰が生み出され,一貫したステレオ化学的結果を示した.
- 観察されたステレオ選択性は,トポケミカル効果に起因した.
結論:
- 表面合成の過程で,反応物質と中間物質の表面配列は (M,P) 移行状態をステリックに好む.
- トポケミカルコントロールは,表面媒介反応において高いステレオ選択性を達成する重要な要因である.
- この研究は,表面上の特定の空間的配置を持つキラル分子の合理的な設計に関する洞察を提供します.
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