缓冲协调调制作为控制晶体形态和分子扩散的手段
Kristen A Colwell1, Megan N Jackson2, Rodolfo M Torres-Gavosto2
1Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720, United States.
Journal of the American Chemical Society
|March 30, 2021
概括
研究人员开发了一种新的方法,通过独立调整pH来控制金属有机框架晶体的大小和形状. 这允许精确调整晶体形态,影响工业应用的客体扩散率.
科学领域:
- 材料科学
- 晶体学
- 化学工程
背景情况:
- 金属有机框架 (MOF) 提供可调的化学环境,但由于不可预测的晶体大小和形状,在材料开发方面面临挑战.
- 控制晶体生长通常涉及协调调节器,这可能无意中改变溶液的pH值,使形态控制复杂化.
- 在MOF合成中,pH和协调物种之间的相互作用仍然是研究的关键领域.
研究的目的:
- 使用非协调缓冲器在MOF合成过程中独立控制反应pH.
- 阐明协调物种在影响MOF晶体生长和形态上的具体作用.
- 为定制MOF晶体形状及其对客体扩散的影响制定预测策略.
主要方法:
- 使用非协调性缓冲器在MOF合成过程中保持7的恒定pH值.
- 使用乙酸合成的低分散性单晶二氧化碳.
- 使用密度功能理论 (DFT) 计算来分析乙与的结合相互作用.
- 具有不同碳酸盐离子的多种 (II) 盐,研究它们对晶体生长方向的影响.
- 应用零长度列色谱来评估晶体形态对m-xylen扩散的影响.
主要成果:
- 通过独立控制pH,成功合成了CO2的单晶.
- DFT计算证实了酸盐在结晶过程中与的竞争性结合.
- 证明了碳酸盐离子的协调强度的变化可以控制c方向的晶体生长.
- 显示了MOF晶体形态与m-xylen扩散路径长度之间的直接相关性.
结论:
- 在MOF合成中,非协调缓冲器提供了一种强大的工具,可以将pH效应与调节器效应脱.
- 晶体形态显著影响客体扩散率,对MOF应用有影响.
- 这项工作提供了分子层面的见解和控制MOF结晶体形态和优化扩散特性的实用策略.
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