SerialED has been successful in characterizing structures of zeolites 8, 9 and proteins 10. Although this is generally performed under cryogenic conditions, some success has been reported using room-temperature 3D ED on radiation sensitive metal–organic frameworks with low-dose rotational scans 11. Three-dimensional electron diffraction (3D ED, also known as MicroED) 4, 5, 6, 7 and serial electron diffraction 8, 9, 10 have also attracted attention for structure determination of nano- and microcrystals. When unknowns are characterized, the solution step is often model-assisted, for example, by simulated annealing 24, 25. Therefore, Rietveld refinement is often more suitable for known structures or those with known homologues 22, 23. In PXRD work, peak broadening arises from sample-based and instrument-based factors and complicates the search for a unit cell and the measurement of structure factors. smSFX is a general method with which to structurally characterize microcrystalline, low-symmetry and radiation-sensitive materials.Įlectron diffraction and powder X-ray diffraction (PXRD) are currently the dominant techniques for structural studies on microcrystals. Although the Ag–E coordination is similar in all three systems, we find a motif of linear Ag–Ag interactions in thiorene that provides insight into its lack of optical emission compared to the trigonal planar Ag–Ag network in the other two. We first validate the method against the known structure of mithrene before presenting the previously unknown structures of the homologues thiorene, AgSC 6H 5, and tethrene, AgTeC 6H 5. In this work, we present the room-temperature (298 K) crystal structures of all three materials as determined by X-ray free-electron laser (XFEL) small-molecule serial femtosecond crystallography (smSFX). As an example, the structure of the excitonic and blue-emitting mithrene, AgSeC 6H 5, was determined by SCXRD 18, 19, 20 but the remaining and optically divergent silver benzenechalcogenolates (AgEC 6H 5, E = S, Te) have not yielded to characterization by Rietveld refinement or micro-electron diffraction 21. Powder diffraction and electron microdiffraction are established methods for determining structures of microcrystalline substances, but each can be limited by some combination of the challenges above. Frequently encountered challenges for SCXRD include difficulty in crystal growth, instability to atmosphere, solvent loss and radiation sensitivity. Single-crystal X-ray diffraction (SCXRD) is a foundational characterization technique for chemistry and materials science, with over one million published organic and metal–organic structures 2, 3. We demonstrate that smSFX can be applied as a general technique for structure determination of beam-sensitive microcrystalline materials at near-ambient temperature and pressure. In thiorene, we identify a geometric change in the silver–silver bonding network that is linked to its divergent optoelectronic properties 20. We describe the ab initio structure solutions of mithrene (AgSePh) 18, 19, 20, thiorene (AgSPh) and tethrene (AgTePh), of which the latter two were previously unknown structures. After indexing the sparse serial patterns by a graph theory approach 14, the resulting datasets can be solved and refined using standard tools for single-crystal diffraction data 15, 16, 17. ![]() ![]() We determined unit cells by aggregating spot-finding results into high-resolution powder diffractograms. We subjected microcrystalline suspensions to X-ray free-electron laser radiation 12, 13 and obtained thousands of randomly oriented diffraction patterns. ![]() Here we demonstrate small-molecule serial femtosecond X-ray crystallography (smSFX) for the determination of material crystal structures from microcrystals. ![]() This proliferation has led to a characterization bottleneck: many hybrid materials are obligate microcrystals with low symmetry and severe radiation sensitivity, interfering with the standard techniques of single-crystal X-ray diffraction 2, 3 and electron microdiffraction 4, 5, 6, 7, 8, 9, 10, 11. Inorganic–organic hybrid materials represent a large share of newly reported structures, owing to their simple synthetic routes and customizable properties 1. Nature volume 601, pages 360–365 ( 2022) Cite this article Chemical crystallography by serial femtosecond X-ray diffraction
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