无序示例-乙二胺阳离子二重无序

DJ_Tokyo

相关软件或概念：Olex2[1] (Version: Olex2-1.5); SHELXL[2] (Version: SHELXL-2019/3); PLATON[3] (Version: 60124); SHELXT[4]

最近，佳木斯某高校友友求助处理一个晶体数据，最大的两个残余峰Q1和Q2处于乙二胺附近，与两个碳原子形成交错状态，整个乙二胺只有N3椭球正常，其余三个原子椭球均严重拉长变形，如图1所示。

▲图1 乙二胺原子椭球状态及残余峰

显然该乙二胺分子需要做无序处理，以N3为支点，将其余三个原子做二组分无序并让两个碳原子和残余峰拟合，用SAME指令（参阅推文“SHELXL指令之SAME”）和SIMU指令（参阅推文“SHELXL指令之SIMU”）分别对两个无序组分的几何结构和原子各向异性位移参数进行限制，结果如图2所示，乙二胺两个无序组分的原子椭球均正常，且附近无异常残余峰。

▲图2 乙二胺无序处理结果

参考文献

[1]Dolomanov, O. V.; Bourhis, L. J.; Gildea, R. J.; Howard, J. A. K.; Puschmann,H. OLEX2: A complete structure solution,refinement and analysis program. J. Appl. Cryst. 2009, 42, 339–341.

[2](a) Sheldrick, G. M. SHELXL-2019/3, Program for Crystal Structure Refinement,University of Göttingen, Germany, 2019. (b) Sheldrick, G. M. A short history ofSHELX. Acta Cryst. 2008, A64, 112–122. (c) Sheldrick, G. M.Crystal structure refinement with SHELXL.Acta Cryst. 2015, C71, 3–8. (d)Lübben, J.; Wandtke, C. M.; Hübschle, C. B.; Ruf, M.; Sheldrick, G. M.;Dittrich, B. Aspherical scattering factors for SHELXL – model, implementation and application. Acta Cryst. 2019, A75, 50–62.

[3] (a) Spek, A. L. Single-crystal structure validationwith the program PLATON. J. Appl.Cryst. 2003, 36, 7–13. (b) Spek,A. L. Structure validation in chemical crystallography. Acta Cryst. 2009, D65, 148–155. (c) Spek, A. L. What makes a crystal structure reportvalid? Inorg. Chim. Acta 2018, 470, 232–237. (d) Spek, A. L. checkCIFvalidation ALERTS: what they mean and how to respond. Acta Cryst. 2020, E76, 1–11.

[4]Sheldrick, G. M. SHELXT – Integratedspace-group and crystal structure determination. Acta Cryst. 2015, A71, 3–8.

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