灵活性的优势:在含有C-H··F相互作用的晶体结构中的作用
Cameron J G Wilson1, Jan Plesniar1, Heike Kuhn1
1Centre for Science at Extreme Conditions, School of Chemistry, The University of Edinburgh, King's Buildings, West Mains Road, Edinburgh EH9 3FJ, U.K.
Crystal growth & design
|March 11, 2024
概括
弱C-H···F相互作用显著稳定分子晶体通过,而不仅仅是. 这些相互作用同样有助于键,影响晶体结构的稳定性.
科学领域:
- 固态化学 固态化学
- 分子相互作用分子相互作用.
- 晶体学 晶体学是指结晶学.
背景情况:
- 分子晶体结构通常通过强相互作用 (如键和π堆叠) 来分析.
- 弱相互作用,尽管它们的累积意义,由于它们的微妙性质和缺乏定义的几何形状,经常被忽视.
- 这些弱相互作用对晶体稳定的性贡献尚未完全理解.
研究的目的:
- 研究C-H···F相互作用在稳定分子晶体结构中的热贡献.
- 量化弱相互作用对晶体二衍生物总体稳定性的作用.
- 为了比较C-H···F相互作用的稳定作用与更成熟的分子间力.
主要方法:
- 使用周期密度函数理论 (DFT) 计算,计算了五种甲衍生物的值.
- 计算的值与不弹性中子散射数据和实验热容量测量结果进行了验证.
- 分析了C-H··F接触的力常数,并与键,键和C-H···π相互作用的力常数进行了比较.
主要成果:
- 计算准确地重现了实验数据,证实了计算的有效性.
- 与键,键和C-H··π相互作用相比,C-H··F接触的强力常数较低.
- C-H···F 相互作用的可变性导致低能振动模式,在 150 K (-10 到 -15 kJ mol-1) 时提供显著的稳定性热贡献.
结论:
- 弱C-H··F相互作用在稳定分子晶体方面起着至关重要的作用,提供与强键相比的稳定.
- 接触C-H··F的频率高于单独由体贡献预测的频率,突出显示了体因素的重要性.
- 了解弱相互作用的性贡献对于全面分析分子晶体结构及其稳定性至关重要.
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