无序示例-氯丁基二重分无序

DJ_Tokyo

无序示例-氯丁基二重分无序

文本所用软件/程序

GUI: Olex2[1]    Structure refinement: SHELXL[2]    Crystallographic tool: PLATON[3]

案例来源：CCDC[4] 2381945, DOI[5]:10.5517/ccdc.csd.cc2kyly2.

案例结构如图1所示。

▲图1 案例结构

如图2所示，虽然没有AB级警报，但差值电子密度图显示氯丁基附近有较大残余峰，MaxPeak约为1.1。

▲图2 残余峰

对该氯丁基做二组分无序处理，使第二组分与残余峰拟合，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。无序处理后，Max Peak降为0.4，R因子也大幅度下降，C级警报的数量也大幅减少，如图3所示。

▲图3 无序处理结果

视频演示操作请参阅：

单晶结构解析练习174(数据还原-非预期结构)：https://www.bilibili.com/video/BV1LUH9exEMW

如需数据进行练习，请从以下链接下载：

链接:https://pan.baidu.com/s/1wBW7yB5wwAt6QjEiH-wW1w

提取码: gr3a

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. DOI: 10.1107/S0021889808042726.    [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 of SHELX.  Acta Cryst. 2008, A64, 112–122. DOI: 10.1107/S0108767307043930. (c) Sheldrick, G. M. Crystal Structure  Refinement with SHELXL. Acta Cryst. 2015, C71, 3–8. DOI: 10.1107/S2053229614024218. (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. DOI:  10.1107/S2053273318013840.    [3] (a)  Spek, A. L. Single-Crystal Structure Validation with the Program PLATON. J. Appl. Cryst. 2003, 36, 7–13. DOI: 10.1107/S0021889802022112. (b) Spek, A. L. Structure Validation in  Chemical Crystallography. Acta Cryst. 2009, D65, 148–155. DOI: 10.1107/S090744490804362X. (c) Spek, A. L. What Makes a Crystal Structure  Report Valid? Inorg. Chim. Acta 2018, 470, 232–237. DOI: 10.1016/j.ica.2017.04.036. (d)  Spek, A. L. checkCIF Validation  ALERTS: What They Mean and How to Respond. Acta Cryst. 2020, E76, 1–11. DOI: 10.1107/S2056989019016244.    [4] (a) Allen, F.  H. The Cambridge Structural Database: a quarter of a million crystal  structures and rising. Acta Cryst. 2002, B58, 380–388. DOI:  10.1107/S0108768102003890.  (b) Allen, F. H. The Cambridge Structural Database: a quarter of a million  crystal structures and rising. Acta  Cryst. 2016, B72, 171–179. DOI:  10.1107/S2052520616003954.    [5] (a) International Organization for Standardization  (2012). ISO 26324:2012. Information and  Documentation – Digital Object Identifier System.  http://www.iso.org/iso/catalogue_detail.htm?csnumber=43506. (b) McDonald J.  D.; Levine-Clark, M. Encyclopedia of  Library and Information Sciences. Fourth Edition, CRC Press, 2017. DOI: 10.1081/e-elis4.  (c) Liu, J. Digital Object Identifier (DOI) and DOI Services: An Overview. Libri 2021, 71, 349‒360. DOI: 10.1515/libri-2020-0018. (d) International Organization for Standardization  (2022). ISO 26324:2022. Information and  Documentation – Digital Object Identifier System. https://www.iso.org/standard/81599.html

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