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Cu (I) - ディアゼン複合体における無害なリドックス水素結合を解明する
Evan J Gardner1, Sean C Marguet2, Caitlyn R Cobb1
1Department of Chemistry, Georgetown University, Box 51277-1227, Washington, D.C. 20057, United States.
Journal of the American Chemical Society
|September 21, 2021
まとめ
この研究は,アンモニア合成のための中間窒素を安定化するために,銅複合体内の分子内H結合を調査する. H結合は二重の水素原子移転を促進し,窒素固定のための新しい経路を提供します.
科学分野:
- 無機化学
- 有機金属化学
- カタリシス
背景:
- 窒素 (N2) をアンモニア (NH3) に還元することは不可欠ですが,ダイアゼン (N2H2) のような高エネルギー中間物質のために運動的に困難です.
- これらの反応性中間物質を安定させる戦略として,分子内水素結合 (H結合) が研究されている.
研究 の 目的:
- 銅複合体内のダイアゼン中間物質の安定化における分子内H結合の役割を調査する.
- 窒素固定における反応経路に影響を与えるH結合の可能性を調査する.
主な方法:
- ペンダントの芳香性N-ヘテロサイクル (xHet) を含む[TpCu]2[μ-N2H2]複合体の合成とX線結晶学.
- 赤外線 (IR) 光譜と低温1H NMRの研究で,H結合とダイナミックバランスを特徴付けます.
- 電子構造と反応経路を分析するための密度関数理論 (DFT) の計算.
- N−N結合の振動変化を研究するための共振ラーマン光譜法.
主要な成果:
- ペンダントのN-ヘテロサイクルとブリッジングのN2H2リガンドの間のH結合は[pyMeTpCu]2[μ-N2H2]で確認された.
- DFTとNMRの研究では,対称なH結合モチーフの間の動的均衡が示されました.
- レゾナンスのラマン研究では,H結合によるNN結合の振動に重大な変化が示された.
- DFTの計算は,N2H2からxHetへの協調された二重水素原子移転 (HAT) が熱力学的に有利な経路であることを示した.
結論:
- [TpCu]2 ((μ-N2H2) コンプレックスにおける分子内H結合は,ダイアゼンの中間物質を効果的に安定させる.
- レドックス非無害なH結合は,N2H2から部分的なH原子移転を促進する.
- N2/N2H2の相互変換は,窒素固定触媒にとって有効な経路を示しています.
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