変温19FのNMRと1,9と1,7-C60F (CF3) とC (s) -とC1-C60F (CF17) の理論的研究:CF3の回転が妨げられ,宇宙中J (FF) カップリングが阻害された
Ivan E Kareev1, Gustavo Santiso Quiñones, Igor V Kuvychko
1Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka 142432 Russia.
Journal of the American Chemical Society
|August 11, 2005
まとめ
研究者は新しいフルレンの誘導体であるC60F (CF3) とC60F (CF3) を精製し,その構造を研究した. 温度変数19F NMRは,これらのフッ素フルレンのトリフローロメチル群の回転が妨げられていることを明らかにしました.
科学分野:
- フラーレンの化学
- オーガノフッ素化学 オーガノフッ素化学
- 核磁共振スペクトロスコーピー 核磁共振スペクトロスコーピー
背景:
- フーラーレンは,ユニークな電子的および構造的特性を有する炭素のアロトロップです.
- フラーレンの機能化,特にフッ素およびトリフッ素メチル基は,その性質の調節に極めて重要です.
- フラーレンケージの置換剤のダイナミクスと相互作用を理解することは,それらの適用の鍵です.
研究 の 目的:
- 新しいフッ素フルレン誘導体,特にC60F (CF3) とC60F (CF3) を分離し,浄化する.
- 温度変数19FNMRを用いたフルレン誘導体のトリフローロメチル (CF3) 群の回転ダイナミクスを調査する.
- これらのフッ素フルレンにおける支配的な核スピン・スピン結合メカニズムを解明する.
主な方法:
- C60/K2PtF6反応混合物から新しいフルレン化合物のミリグラムの量を分離.
- BuckyprepとBuckyclutcherコラムを使用した二次元高性能液体染色体 (2D-HPLC) を使用して,高構成純度 (>90-98 mol %) に浄化.
- 変温19F核磁気共鳴 (NMR) スペクトロスコピーは,CF3群の回転とフッ素-フッ素 (F-F) 結合を研究する.
主要な成果:
- 1,9-および1,7-C60F (CF3) とC60F (CF3) の同位体と,以前に報告されたC60F (CF3) とC60F (CF5) とC60F (CF7) の同位体との分離と浄化が成功しました.
- 遅い交換限界の実証は, -40 ± 10 °Cで隣接する置換物とのフルレネ ((F) n ((CF3) m誘導体におけるCF3の回転を妨げました.
- CF3の回転のための実験的およびDFTで予測された活性化エネルギー (ΔH‡) の決定と,空間を通るF-F結合定数の分析 ((≥4) JFF).
結論:
- この研究は,特定のフッ素フルレンの誘導体におけるCF3回転の妨げられた最初の証拠を提供します.
- トゥルー・スペース・カップリングは,フッ素原子間の支配的な核スピン・スピン・カップリングメカニズムとして特定されています.
- 得られたNMRデータは,フラーレンの誘導体に関する将来の研究と計算上の予測のための貴重な参考資料として役立つ.
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