熱力学的な安定性は,有機分子モデルにおける共結晶化の悪い指標である
Yulia Pimonova1, John E Carpenter1, Michael Gruenwald1
1Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States.
Journal of the American Chemical Society
|January 19, 2024
まとめ
固体状態の性質を変化させるコクリステル化は,しばしば予測不可能である. この研究は,安定した共結晶が熱力学的に可能である場合でも,動的要因がしばしば共結晶化を防ぐことを明らかにし,ダイナミックなプロセスの重要性を強調しています.
科学分野:
- 固体化学
- 材料科学
- コンピュータ化学
背景:
- 固体状態の分子特性を調整する鍵です
- ほとんどの分子ペアは共結晶化に失敗し,単一成分結晶または無形固体を形成する.
- 同結晶化の予測は,計算による結晶構造の予測に依存しているが,運動的要因はしばしば見過ごされている.
研究 の 目的:
- 熱力学的に安定した共結晶が共結晶化を保証するかどうかを調査する.
- 同結晶化結果を予測する熱力学的基準の信頼性を評価する.
- 同結晶化成功に対する運動要因の影響を調査する.
主な方法:
- 2Dのキラルモデル分子の2600以上のペアの結晶をシミュレートした.
- すべてのシミュレートシステムのための正確なクリスタルエネルギー風景を計算した.
- 熱力学的安定性と観察された共結晶化の関係を分析した.
主要な成果:
- 熱力学的な安定性だけでは,共結晶化の予測には信頼できない.
- 熱力学的に好ましい共結晶を持つほとんどのシステムは共結晶化しなかった.
- コクリスタル化率は,より秩序が低い単一成分結晶を形成するコフォーマーを使用すると3倍に増加した.
結論:
- 同結晶化の結果には,運動的要因が決定的な役割を果たします.
- 熱力学的に安定したコクリスタルの形成は,実際にはそれらの形成を保証しません.
- 運動的障壁を理解することは,成功するコクリステル化の予測と達成に不可欠です.
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