Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden.
Faraday Discuss. 2021 Feb 1;225:118-132. doi: 10.1039/d0fd00015a. Epub 2020 Oct 29.
Many framework materials such as metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) are synthesized as polycrystalline powders, which are too small for structure determination by single crystal X-ray diffraction (SCXRD). Here, we show that a three-dimensional (3D) electron diffraction method, namely continuous rotation electron diffraction (cRED), can be used for ab initio structure determination of such materials. As an example, we present the complete structural analysis of a biocomposite, denoted BSA@ZIF-CO-1, in which Bovine Serum Albumin (BSA) was encapsulated in a zeolitic imidazolate framework (ZIF). Low electron dose was combined with ultrafast cRED data collection to minimize electron beam damage to the sample. We demonstrate that the atomic structure obtained by cRED is as reliable and accurate as that obtained by single crystal X-ray diffraction. The high accuracy and fast data collection open new opportunities for investigation of cooperative phenomena in framework structures at the atomic level.
许多框架材料，如金属-有机骨架（MOFs）或多孔配位聚合物（PCPs），都是作为多晶粉末合成的，对于单晶 X 射线衍射（SCXRD）来说，这些粉末太小，无法进行结构测定。在这里，我们展示了一种三维（3D）电子衍射方法，即连续旋转电子衍射（cRED），可用于此类材料的从头算结构确定。作为一个例子，我们介绍了一种生物复合材料 BSA@ZIF-CO-1 的完整结构分析，其中牛血清白蛋白（BSA）被封装在沸石咪唑骨架（ZIF）中。低电子剂量与超快 cRED 数据采集相结合，以最小化电子束对样品的损伤。我们证明了通过 cRED 获得的原子结构与通过单晶 X 射线衍射获得的原子结构一样可靠和准确。高准确性和快速的数据采集为在原子水平上研究框架结构中的协同现象开辟了新的机会。
