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
<i>ab initio</i> structure determination of such
materials. As an example, we present a complete structural analysis of a biocomposite,
denoted BSA@ZIF-C, where Bovin 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 of 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 atomic level.
3D electron diffraction as an important technique for structure elucidation of metal-organic frameworks and covalent organic frameworks
