美国科罗拉多大学博尔德分校Wei Zhang研究团队，报道了通过共价有机框架中的温度调节振荡进行分辨率低于0.2埃的分子识别。相关研究成果发表在2024年6月28日出版的国际学术期刊《科学》。

具有均匀分子大小孔隙的结晶材料适用于广泛的应用，如传感器、催化和分离。然而，连续地调节单个材料的孔径并可逆地区分小分子（低于4埃）是具有挑战性的。

研究人员使用四苯氧基硼酸盐键合成了一系列离子共价有机框架，该键保持结构刚性和局部柔性之间的精细协同作用，以实现2.9埃至4.0埃之间的“动态孔隙”的连续和可逆（100个热循环）可调谐性，分辨率低于0.2埃。这是由高频接头振荡的温度调节、振幅逐渐变化引起的。

这些热弹性孔隙选择性地阻挡较大的分子而不是稍小的分子，证明了基于尺寸的分子识别以及分离具有挑战性的气体混合物（如氧气/氮气和氮气/甲烷）的潜力。

附：英文原文

Title: Molecular recognition with resolution below 0.2 angstroms through thermoregulatory oscillations in covalent organic frameworks

Author: Yiming Hu, Bratin Sengupta, Hai Long, Lacey J. Wayment, Richard Ciora, Yinghua Jin, Jingyi Wu, Zepeng Lei, Kaleb Friedman, Hongxuan Chen, Miao Yu, Wei Zhang

Issue&Volume: 2024-06-28

Abstract: Crystalline materials with uniform molecular-sized pores are desirable for a broad range of applications, such as sensors, catalysis, and separations. However, it is challenging to tune the pore size of a single material continuously and to reversibly distinguish small molecules (below 4 angstroms). We synthesized a series of ionic covalent organic frameworks using a tetraphenoxyborate linkage that maintains meticulous synergy between structural rigidity and local flexibility to achieve continuous and reversible (100 thermal cycles) tunability of “dynamic pores” between 2.9 and 4.0 angstroms, with resolution below 0.2 angstroms. This results from temperature-regulated, gradual amplitude change of high-frequency linker oscillations. These thermoelastic apertures selectively block larger molecules over marginally smaller ones, demonstrating size-based molecular recognition and the potential for separating challenging gas mixtures such as oxygen/nitrogen and nitrogen/methane.

DOI: adj8791

Source: https://www.science.org/doi/10.1126/science.adj8791