1,8-ビス (hexamethyltriaminophosphazenyl) ナフタレン,HMPN: 超基本的なビスホスファレン"陽子スポンジ"である
Volker Raab1, Ekaterina Gauchenova, Alexei Merkoulov
1Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany.
Journal of the American Chemical Society
|November 10, 2005
まとめ
新しいスーパーベースであるHMPNは,フォスファゼンとナフタレン構造を組み合わせ,前例のない基本性を示しています. この陽子スポンジは,そのユニークな構造と分子内水素結合により,DMANよりも10^11倍以上基本的なものです.
科学分野:
- 有機化学 オーガニック・ケミストリー
- 超分子化学 超分子化学
背景:
- 強い有機基の開発は,様々な化学応用において極めて重要です.
- 1,8-bis(dimethylamino) naphthalene (DMAN) のようなプロトンスポンジは,その高い基本性で知られている.
- Schwesingerのフォスファゼン塩基は,強力な有機塩基の別のクラスを表しています.
研究 の 目的:
- フォスファゼンと1,8-ナフタレン構造モチーフを組み合わせて新しいスーパーベースを合成し,特徴づけること.
- 新型化合物の基本性を評価し,既存の陽子スポンジとフォスファゼン塩基と比較する.
- 強化された基本性に寄与する構造的および電子的要因を解明する.
主な方法:
- 新型化合物HMPNの合成と完全な特徴付け.
- X線結晶学を用いたHMPNとその結合酸の空間構造の決定.
- 陽子相性 (PA) と密度関数理論 (DFT) 計算の理論的推定.
- アセトニトリル (MeCN) のpK (((BH+) の測定.
主要な成果:
- 新しいスーパーベースであるHMPNが成功裏に合成され,特徴づけられました.
- HMPNは,理論的なPAが274kcal/molで,測定されたpK (((BH+) (MeCN) が29.9.である例外的に高い基本性を示しています.
- HMPNは1,8-ビス・ディメチラミノ・ナフタレン (DMAN) よりも10^11倍以上塩基的である.
- X線結晶学とDFT計算により,HMPN.のモノプロトン化形態の非対称な分子内水素ブリッジが明らかになった.
- DFTの計算は,中性塩基のエネルギー含量と結合酸の分子内水素結合から高塩基度が生じることを確認した.
結論:
- フォスファゼンと1,8-ナフタレン構造の組み合わせにより,非常に効果的なスーパーベースが得られます.
- 結合酸内の分子内水素結合は,HMPNの強化された基本性に大きく寄与する.
- HMPNは,陽子スポンジのクラスで新しい基準を代表し,既存の化合物を基本性で上回ります.
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