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★声明：本文仅代表个人观点，笔者学识有限，资料整理过程中可能存在疏漏错误，请不吝指正。 晶体结构不是预期结构案例24 案例70： 本来是按照如图70所示（由ChemBioDraw [1]绘制），利用硝酸钴六水合物（Co(NO3)2·6H2O, Cobalt nitrate hexahydrate, CAS: 10026-22-9）和配体在N,N-二甲基甲酰胺 [2]（DMF, N,N-dimethylformamide,CAS: 68-12-2, CCDC: 102756 [2a], 1869635–1869638[2b], 1869744–1869752 [2b]）、N,N-二甲基乙酰胺（DMA, N,N-Dimethylacetamide,CAS: 127-19-5）、水 [3]（H2O,water, CAS: 7732-18-5, CCDC: 2080050–2080051）和硝酸[4]（HNO3, nitric acid, CAS: 7697-37-2, CCDC:754934–754936）混合溶剂中在一定条件下反应，以期合成含该配体的钴配合物，然而所得晶体经单晶X射线衍射（SC-XRD, singlecrystal X-ray diffraction）实验得到晶体数据，解析后发现该晶体结构为甲酸钴二水合物（Co(HCOO)2·2H2O），显然，在该反应条件下，配体未能与金属结合，而甲酸 [5]（HCOOH, formic acid,CAS: 64-18-6, CCDC: 1159366 [5a], 1159366 [5b], 640128 [5c]）显然来源于DMF的分解（参阅推文“DMF和DEF会为晶体结构带来什么”）。
▲图70 案例70反应示意图 相关视频： 单晶结构解析练习750(数据还原-非预期结构-残余峰-AB级警报)：https://www.bilibili.com/video/BV1akwRzFEao 案例71： 本来是按照如图71所示，利用4,4'-二甲氧基-2,2'-联吡啶 [6]（4,4'-dimethoxy-2,2'-bipyridine,CAS: 17217-57-1, CCDC: 1414484）和某金属盐在一定条件下反应，以期得到含该联吡啶配体配位的金属配合物，然而所得晶体经SC-XRD实验得到晶体数据，解析后发现该晶体结构为该联吡啶配体的盐酸盐，显然，在该反应条件下，配体未能与金属结合。
▲图71 案例71反应示意图 相关视频： 单晶结构解析练习752(非预期结构-氢键-HTAB用法)：https://www.bilibili.com/video/BV156AJzBERv 案例72： 本来是按照如图72所示，利用三氟甲磺酸铕（Eu(OTf)3, Europium(III)trifluoromethanesulfonate, CAS: 52093-25-1）和卤化四甲铵及有机配体在一定条件下反应，以期合成得到含该配体的铕配合物，然而所得晶体经SC-XRD实验得到晶体数据，解析后发现该晶体结构为四甲铵三氟甲磺酸盐[Me4N][OTf]，显然，在该反应条件下，配体未能与金属结合。
▲图72 案例72反应示意图 相关视频： 单晶结构解析练习753(非预期结构-特殊无序)：https://www.bilibili.com/video/BV1kDA3zZEVD 参考文献 [1] (a)Klein, F. M. CS ChemDraw Pro,1 Version 3.1 for Windows. J. Chem. Inf. Comput. Sci. 1995, 35, 166–167. DOI: 10.1021/ci00023a026. (b)Cousins, K. R. ChemDraw 6.0 Ultra CambridgeSoft Corporation, 100 Cambridge ParkDrive, Cambridge, MA 02140. http://www.camsoft.com. Commercial Price: $1395.Academic Price: $699. J. Am. Chem. Soc. 2000, 122, 10257–10258. DOI: 10.1021/ja0047572.(c) Buntrock, R. E. ChemOffice Ultra 7.0. J. Chem. Inf. Comput. Sci. 2002, 42, 1505–1506. DOI: 10.1021/ci025575p. (d) Li, Z.; Wan, H.; Shi, Y.;Ouyang, P. Personal Experience with Four Kinds of Chemical Structure DrawingSoftware: Review on ChemDraw, ChemWindow, ISIS/Draw, and ChemSketch. J. Chem. Inf. Comput. Sci. 2004, 44, 1886–1890. DOI: 10.1021/ci049794h.(e) Mendelsohn, L. D. ChemDraw8 Ultra, Windows and Macintosh Versions. J. Chem. Inf. Comput. Sci. 2004, 44, 2225–2226. DOI: 10.1021/ci040123t. (f) Cousins, K. R. ChemDrawUltra 9.0. CambridgeSoft, 100 CambridgePark Drive, Cambridge, MA 02140. www.cambridgesoft.com. See Web site for pricing options. J. Am. Chem. Soc. 2005, 127, 4115–4116. DOI:10.1021/ja0410237. (g) Zielesny, A. Chemistry Software PackageChemOffice Ultra 2005. J. Chem. Inf.Model. 2005, 45, 1474–1477. DOI:10.1021/ci050273j. (h) Mills, N. ChemDraw Ultra 10.0 CambridgeSoft, 100CambridgePark Drive, Cambridge, MA 02140. www.cambridgesoft.com. CommercialPrice: $1910 for download, $2150 for CD-ROM; Academic Price: $710 fordownload, $800 for CD-ROM. J. Am. Chem. Soc. 2006, 128, 13649–13650. DOI: 10.1021/ja0697875. (i) Kerwin, S. M.ChemBioOffice Ultra 2010 Suite. J. Am. Chem. Soc. 2010, 132, 2466–2467. DOI: 10.1021/ja1005306. (j) Milne, G. W. A. SoftwareReview of ChemBioDraw 12.0. J. Chem. Inf.Model. 2010, 50, 2053. DOI:10.1021/ci100385n. (k) Narayanaswamy, V. K.; Rissdörfer, M.; Odhav, B.Review on CambridgeSoft ChemBioDraw Ultra 13.0v. Int. J. Theor. Appl. Sci. 2013, 5, 43–49. [2] (a)Borrmann, H.; Persson, I.; Sandström, M.; Stålhandske, C. M. V. The Crystal andLiquid Structures of N,N-Dimethylthioformamide and N,N-DimethylformamideShowing a Stronger Hydrogen Bonding Effect for C–H⋯S than of C–H⋯O. J.Chem. Soc. Perkin Trans. 2 2000, 393–402. DOI:10.1039/a904531g. (b) Ratajczyk, P.; Sobczak, S.; Katrusiak, A. High-PressureStructure and Properties of N,N-Dimethylformamide (DMF). Cryst.Growth Des. 2019, 19, 896–901. DOI: 10.1021/acs.cgd.8b01452. [3] Salzmann, C.G., Loveday, J.S., Rosu-Finsen, A.;Bull, C. L. Structure and nature of ice XIX. Nat. Commun. 2021, 12, 3162. DOI: 10.1038/s41467-021-23399-z. [4] Allan, D. R.; Marshall,W. G.; Francis, D. J.; Oswald, I. D. H.; Pulham, C. R.; Spanswick, C. TheCrystal Structures of the Low-Temperature and High-Pressure Polymorphs ofNitric Acid. Dalton Trans. 2010, 39, 3736–3743. DOI: 10.1039/b923975h. [5] (a)Holtzberg, F.; Post, B.; Fankuchen, I. The Crystal Structure of Formic Acid. ActaCryst. 1953, 6, 127–130. DOI:10.1107/S0365110X53000478. (b) Nahringbauer, I. A Reinvestigation of theStructure of Formic Acid (at 98 K). Acta Cryst. 1978, B34,315–318. DOI: 10.1107/S0567740878002940. (c) Allan,D. R.; Clark, S. J. Impeded Dimer Formation in the High-Pressure CrystalStructure of Formic Acid. Phys. Rev. Lett. 1999, 82, 3464–3467.DOI: 10.1103/PhysRevLett.82.3464. [6] Kusano, Y.; Ohno,K.; Fujiara, T. Crystal Structure of 4,4′-Dimethoxy-2,2′-bipyridine. ActaCryst. 2015, E71, o623–o624. DOI: 10.1107/S2056989015013985.
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