真のMOFポリモルフの安定性の実験的および理論的評価は,それらのメカノ化学的相互変換を説明する
Zamirbek Akimbekov1, Athanassios D Katsenis2, G P Nagabhushana1
1Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California, Davis , One Shields Avenue, Davis, California 95616, United States.
Journal of the American Chemical Society
|May 19, 2017
まとめ
この研究は,リガンド構造とフレームワークトポロジが金属有機フレームワーク (MOF) の安定性に大きく影響することを明らかにしている. リガンド置換剤の影響を受けたより密度の高いMOFポリモルフは,熱力学的により安定している.
科学分野:
- 材料科学
- 化学について
- クリスタルグラフィー
背景:
- メタル・オーガニック・フレームワーク (MOF) は,調節可能な性質を持つ多用性のある多孔性材料です.
- MOFポリモルファの安定性を支配する要因を理解することは,その標的の合成と適用にとって極めて重要です.
- 同組成MOFまたは真のポリモルフは,同じ化学組成を共有するが,構造と特性によって異なる.
研究 の 目的:
- 同組成MOFの相対的な安定性に対するリガンド構造とフレームワークトポロジーの影響を実験的および理論的に評価する.
- 亜鉛ゼオリティイミダゾラートフレームワーク (ZIF) の熱力学的安定性を,異なるリガンド置換物質とトポロジーで調査する.
- MOFの密度と安定性をリガンド構造とフレームワークトポロジーと相関させる.
主な方法:
- ZIFポリモルフの熱力学的安定性を測定するために溶液カロミテリーを使用した.
- 理論的評価には周期密度関数理論 (DFT) の計算を用いた.
- 2メチルおよび2エチリミダゾラートリンカーに基づく2つのZIFファミリーを分析した.
主要な成果:
- 測定された熱力学的安定性とZIFポリモルフの密度との間には直接的な相関が観察された.
- リガンド置換剤は,ZIFの安定性に顕著な効果があることが判明しました.
- ZIFの機械化学合成と変換はオストワルドの段階規則に適合し,より密集した,より安定した段階を好みます.
結論:
- リガンド構造とフレームワークトポロジは,MOFの多形安定性の重要な決定因子である.
- MOFの密度の増加は熱力学的安定性の向上と相関する.
- 機械化学的条件下でのMOF変換は,熱力学的に好ましい,より密度の高い構造へと進みます.
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