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Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
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2-(3,5-ディニトロフェニル) -1,3-ディシアンカルバニオン: 低エネルギートリプル状態のベンジルアニオン
Raffaele R Perrotta1, Arthur H Winter, William H Coldren
1Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742-2021, United States.
Journal of the American Chemical Society
|August 30, 2011
まとめ
電子を取り除くグループを持つベンジルアニオンは,トリプル電子状態を示すことができます. 実験的および計算的研究により,特定のディニトロフェニルディシアンカルバニオンがトリプレートとして存在するか,または低いトリプレート状態を有することを示唆しています.
科学分野:
- コンピューティング・ケミストリー
- 有機化学 オーガニック・ケミストリー
- 量子化学とは,量子化学である.
背景:
- ベンジルアニオンは通常,シングレット基底状態を持つと考えられます.
- カーバニオンの電子的性質は,置換効果によって調節することができる.
研究 の 目的:
- 強い電子取り除くグループを持つベンジルアニオンの電子状態を調査する.
- これらのアニオンが低い三重体の状態を持つことができるかどうかを判断する.
主な方法:
- 密度関数理論 (DFT) の計算,特に (U) B3 LYP の関数を使用します.
- 化学的トラッピング,核磁共振 (NMR) 光譜,エヴァンズ法を含む実験技術.
主要な成果:
- DFT計算は,メタ置換ベンジルアニオンの低エネルギー二基またはトリプレット状態を予測します.
- 2-(3,5-ディニトロフェニル) -1,3-ディシアンカルバニオンは,自由アニオンとしてほぼ退廃したシングレットおよびトリプレット状態を示します.
- このカルバニオンのリチウムイオンペアは,基底状態のトリプレットであり, singlet-tripleteエネルギーギャップ (26 kcal/mol) が大きいと予測されています.
結論:
- 実験的証拠は,2-(3,5-ディニトロフェニル) -1,3-ディシアンカルバニオンがトリプレートまたはシングレットであり,非常に低エネルギートリプレート状態であるという仮説を支持しています.
- 強いπ電子取り除くグループは,ベンジルアニオンにおけるトリプレート状態を安定させることができる.
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