清华大学魏飞团队提出了一个单分子范德华罗盘。 相关研究成果于2021年4月21如发表在《自然》。
单分子成像具有挑战性,但是在分子水平研究分子间相互作用方面非常有用。亚纳米尺度上的范德华相互作用强烈地影响限制条件下的各种分子行为。
受传统罗盘的的启发,研究人员使用对二甲苯分子作为旋转指针来检测MFI型分子筛骨架直通道中的主客体范德华相互作用。研究人员使用积分差分相位衬度扫描透射电子显微技术(iDPC-STEM)实现了对单个对二甲苯(PX)分子在二维ZSM-5分子筛内的直接成像。将计算结果与成像研究结果相结合,建立了单分子指针取向与通道原子结构之间的良好关联。对二甲苯的取向有助于人们识别在空间和时间维度上都与通道几何结构有关的范德华相互作用的变化。
该研究工作工作不仅为在分子水平上研究多孔材料中的主客体范德华相互作用提供了一种直观、灵敏的手段,而且也促进了利用电子显微镜技术对其他单分子行为的进一步研究。
附:英文原文
Title: A single-molecule van der Waals compass
Author: Boyuan Shen, Xiao Chen, Huiqiu Wang, Hao Xiong, Eric G. T. Bosch, Ivan Lazi, Dali Cai, Weizhong Qian, Shifeng Jin, Xin Liu, Yu Han, Fei Wei
Issue&Volume: 2021-04-21
Abstract: Single-molecule imaging is challenging but highly beneficial for investigating intermolecular interactions at the molecular level1,2,3,4,5,6. Van der Waals interactions at the sub-nanometre scale strongly influence various molecular behaviours under confinement conditions7,8,9,10,11. Inspired by the traditional compass12, here we use a para-xylene molecule as a rotating pointer to detect the host–guest van der Waals interactions in the straight channel of the MFI-type zeolite framework. We use integrated differential phase contrast scanning transmission electron microscopy13,14,15 to achieve real-space imaging of a single para-xylene molecule in each channel. A good correlation between the orientation of the single-molecule pointer and the atomic structure of the channel is established by combining the results of calculations and imaging studies. The orientations of para-xylene help us to identify changes in the van der Waals interactions, which are related to the channel geometry in both spatial and temporal dimensions. This work not only provides a visible and sensitive means to investigate host–guest van der Waals interactions in porous materials at the molecular level, but also encourages the further study of other single-molecule behaviours using electron microscopy techniques.
DOI: 10.1038/s41586-021-03429-y
Source: https://www.nature.com/articles/s41586-021-03429-y