電子パラマグネティック共鳴と電子核二重共鳴のパラメータからの水素結合幾何学:キノンラジカルアニオン-溶媒相互作用の密度関数研究
Sebastian Sinnecker1, Eduard Reijerse, Frank Neese
1Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany.
Journal of the American Chemical Society
|March 12, 2004
まとめ
水素結合は,p-ベンゾセミキノンラジカルアニオン (BQ(*-)) の性質に大きく影響する. 密度関数理論とENDOR実験は,理論的な予測を確認し,水素結合長さの推定に役立ちます.
科学分野:
- コンピューティング・ケミストリー
- 物理化学 物理化学
- スペクトロスコーピーは,スペクトロスコーピーを用います.
背景:
- p-ベンゾセミキノン基素アニオン (BQ(*-)) は,酸化還元過程における重要な種である.
- 溶媒分子との相互作用を理解することは,その振る舞いを予測するために重要です.
研究 の 目的:
- 計算方法を用いて,BQに対する水素結合の影響を調査する.
- 実験データに対して理論的な計算を検証する.
主な方法:
- 密度関数理論 (DFT) は,幾何学最適化とプロパティ計算のためのものです.
- (1) H, (13) C, (17) Oの超精密結合定数, (2) H核四極結合定数,およびg-テンサーのシミュレーション.
- Q帯パルス (2) H電子核二重共鳴 (ENDOR) 実験. 電子核二重共鳴 (ENDOR) 実験. Q帯パルス (2) H電子核二重共鳴 (ENDOR) 実験.
主要な成果:
- DFTの計算は,BQの実験的なENDORスペクトルをD(2) O.で正確に再現しました.
- 計算された水素結合長 (1.75-1.78 Å) は,異なる溶媒 (水,アルコール) において一貫していました.
- 電子パラマグネティック共振 (EPR) パラメータは,異なる溶媒との最小の変動を示しました.
- EPRパラメータと水素結合の長さの間の相関関係が確立されています.
結論:
- DFTは,BQに対する水素結合効果を研究するための信頼できる方法である.
- ポイント・ディポール・モデルは,高精度結合定数から水素結合の長さを効果的に推定します.
- (2) H核四極結合定数から水素結合の長さを推定するために,経験的関係を使用することができます.
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