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-CO₃-1, 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.

中文翻译：

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3D电子衍射能否提供金属-有机骨架的准确原子结构？

许多骨架材料，例如金属有机骨架（MOF）或多孔配位聚合物（PCP），都是多晶粉末合成的，这些粉末太小，无法通过单晶X射线衍射（SCXRD）确定结构。在这里，我们显示了三维（3D）电子衍射方法，即连续旋转电子衍射（cRED），可以用于从头开始确定这种材料。例如，我们介绍了生物复合材料的完整结构分析，表示为BSA @ ZIF-CO ₃-1，其中牛血清白蛋白（BSA）封装在沸石咪唑酸酯骨架（ZIF）中。低电子剂量与超快cRED数据收集相结合，以最大程度地减少电子束对样品的损害。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。高精度和快速的数据收集为原子级框架结构中的合作现象研究提供了新的机会。