水素結合と陽子の移転における酸としての中性過渡金属水化物:媒体の極性および特定の溶解効果
Vladislava A Levina1, Oleg A Filippov, Evgenii I Gutsul
1A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, 119991 Moscow, Russia.
Journal of the American Chemical Society
|August 12, 2010
まとめ
有機金属ヒドリドの弱い水素結合は,陽子転移反応に影響する. 特定の溶媒の相互作用は,予期せぬ形でこの移転を阻害し,化学反応性に影響を与える可能性があります.
科学分野:
- 有機金属化学 有機金属化学
- 物理化学 物理化学
- コンピューティング・ケミストリー
背景:
- CpM ((CO)) ((3) H (M = Mo, W) のような有機金属水素は,化学反応において重要な役割を果たしています.
- 有機塩基との相互作用を理解することは,反応機構の解明に不可欠です.
- これらの水素を含む陽子伝達反応は,触媒と合成において根本的な役割を果たします.
研究 の 目的:
- 弱い水素結合複合体の構造,スペクトル,および電子特性を調査する.
- リバーシブルな陽子転送ステップの熱力学パラメータを決定するために.
- 水素結合と陽子の移転における溶媒効果の役割を明らかにする.
主な方法:
- 温度変数の赤外線 (IR) スペクトロスコピーを用いた実験的決定.
- 密度関数理論 (DFT/M05) と周波数計算を用いた計算分析.
- ヘクサン,ジクロロメタン (CH(2)Cl(2)),テトラヒドロフーラン (THF),アセトニトリル (CH(3) CNの溶媒効果の研究は,IRとコンドクター型の極化連続体モデル (CPCM) の計算を用いて行われました.
主要な成果:
- CpM ((CO)) ((3) H水化物と様々な有機塩基間の弱い水素結合複合体の特徴.
- ヘクサンの可逆性プロトン転送ステップの熱力学パラメータ (ΔH°,ΔS°) の決定.
- 水素結合形成を促進し,陽子伝送均衡に影響を与える特定の溶解効果の特定.
結論:
- 弱い水素結合は,これらの有機金属ヒドリドの陽子転送機構において重要な役割を果たします.
- THFやCH(3) CNのような溶媒との競争力のある弱い相互作用は,ヒドリドと塩基の活性を調節することができます.
- 溶媒の選択は陽子伝送に重大な影響を及ぼし,中性極性溶媒は時には直感に反して非極性ヘクサンと比較して反応を阻害する.
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