晶体数据审稿意见-错用限制指令(PLAT430) 案例来源:CCDC[1] 2396827. RSC Adv.2025, 15, 2645–2650. DOI[2]: 10.1039/d4ra08065c. 审稿意见如下: 审稿意见 | 大意 | Comments: | 评论: | There is 1 structure in this paper. We examined this file: 2396827 | 该论文中有一个结构。我们检查了此文件:2396827 | Thank you for your comments and corrections. | 感谢您的评论和更正。 | **a_sx** (CCDC 2396827) | **a_sx** (CCDC 2396827) | The new cif only includes the absorption correction details of the comments previously made. Currently, the following issues still need addressing: | 新的CIF[3]仅包括先前评论的吸收校正细节。目前,以下问题仍需解决: | - The BASF has refined to 0 so the twin law and BASF should be removed from the ins. | | - A large number of reflections have been omitted using the OMIT command in the ins file and these do not need to be omitted. The SHEL command alone should be left in the file as this cuts the data where I/sigma drops below 3. | | - I note that Squeeze has been used however the formula does not contain the solvent and should, otherwise there are errors in many derived quantities e.g. density, molecular mass, F000 and absorption correction. Please add this in, in line with the IUCr guidance. “The chemical formula must be consistent with the atomic content specified by the _atom_site_ information, and match the _chemical_formula_weight. If atoms are missing from the atomic model (e.g. unlocated H atoms or solvent molecules suppressed by the ‘SQUEEZE’ or similar approach), the moiety and sum formulae should state the assumed overall formula.” Source: https://journals.iucr.org/c/services/cif/reqdata.html | 我注意到使用了SQUEEZE[4],但分子式没有包含(挤掉的)溶剂,实际上应当包含挤掉的溶剂,否则许多衍生量如密度、分子量、F000和吸收校正都会存在误差。请根据IUCr指南添加挤掉的溶剂。“化学式必须与_atom_site_信息指定的原子内容一致,并与_chemical_formula_weight匹配。如果原子模型中缺少原子(例如未确定的氢原子或被‘SQUEEZE’或类似方法抑制的溶剂分子),则单体分子式和总和分子式应说明假定总体分子式。”信源:https://journals.iucr.org/c/services/cif/reqdata.html | - The DFIX 3 0.001 O4 O3_$1 should be removed, this gives a cleaner residual density map in that the region reducing the residuals from 1.6 and -1.4 to 0.5 and -0.6. | 应当删除“DFIX 3 0.001 O4 O3_$1”限制,这会将该区域残余峰从1.6和-1.4将为0.5和-0.6从而得到更加干净的残余密度图。 | - The use of Squeeze should be mentioned in the experimental. Please also check the crystallographic information in the paper after these changes. Thanks very much. | 应在实验部分提及SQUEEZE的使用。按照这些评论更改后,请检查论文中的晶体学信息。非常感谢。 |
▲图1 数据精修情况 ▲图2 B级警报PLAT910 收到审稿意见后,论文作者找笔者处理,作者表示之前是找其他人帮忙处理的,后来联系对方,结果对方不回消息了。 查看结构,发现DFIX指令限制的是与金属配位的羧基氧之间的距离,如图3所示,由于该限制导致羧基氧处的插值电子密度图异常。 ▲图3 异常插值电子密度图 按照审稿意见将删除衍射点的OMIT指令从ins文件中删除,同时删除DFIX、TWIN和BASF等指令,确如审稿人所说,如图4所示,残余峰立马就降低了,羧基处的插值电子密度图也变得很干净,Fobs vs Fcalc图和Bad Reflections列表中都没有任何的离群点,也不知道为何原先帮忙处理的人要用OMIT指令删除大量衍射点。 ▲图4 删除错用限制后的结果 只不过因为与金属配位的羧基氧之间距离小于2.9 Å会触发B级警报PLAT430(参阅推文“CheckCIF-PLAT430”),如图5所示(由PLATON[7]呈现)。 ▲图5 氧原子距离过近触发的B级警报PLAT430 但这个B级警报PLAT430并不是用DFIX强行限制使氧原子距离拉开从而消除的理由,因为这会造成键长键角的不合理,也就是结构的不合理,明显的表现就是插值电子密度图异常,残余峰升高——因为模型与实验数据的拟合度变差了。 不能为了消除警报而消除警报,警报不代表错误,只是一种提醒而已,重要的是尊重实验事实,实事求是! 由于原来的数据做了溶剂遮掩,于是笔者尝试取消溶剂遮掩,将溶剂分子建模出来,大概建模了1.5个水分子,做四组分无序处理,发现不存在B级警报PLAT430,如图6所示。 ▲图6 游离水分子建模结果 但作者强烈要求将游离水分子遮掩掉,于是只能对该B级警报做解释了,如图7所示。 ▲图7 B级警报及其解释 类似情况可参阅如下推文: 视频讲解请参阅: 晶体数据审稿意见-错用限制指令(PLAT430):https://www.bilibili.com/video/BV1r1oZY2END 如需论文PDF和CIF文件,请从以下链接下载: 提取码: rwqk 参考文献 [1] (a) Allen, F. H.The Cambridge Structural Database: A Quarter of a Million Crystal Structuresand Rising. Acta Cryst. 2002, B58, 380–388. DOI:10.1107/S0108768102003890. (b) Groom, C. R.; Bruno, I. J.; Lightfoot, M.P.; Ward, S. C. The Cambridge Structural Database. Acta Cryst. 2016, B72, 171–179. DOI:10.1107/S2052520616003954. (c) Mitchell, J.; Robertson, J. H.; Raithby,P. R. Cambridge Crystallographic Data Centre (CCDC). Comprehensive Coordination Chemistry III 2021, 413–437. DOI:10.1016/B978-0-12-409547-2.14829-2. [2] (a) InternationalOrganization 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 Libraryand Information Sciences. Fourth Edition, CRC Press, 2017. DOI: 10.1081/e-elis4. (c) Liu, J. Digital ObjectIdentifier (DOI) and DOI Services: An Overview. Libri 2021, 71, 349‒360. DOI:10.1515/libri-2020-0018. (d) International Organization forStandardization (2022). ISO 26324:2022. Informationand Documentation – Digital Object Identifier System. https://www.iso.org/standard/81599.html[3] (a) Hall, S. R.;Allen, F. H. Brown, I. D. The Crystallographic Information File (CIF): A NewStandard Archive File for Crystallography. ActaCryst. 1991, A47, 655–685. DOI:10.1107/S010876739101067X. (b) Hall, S. R. The STAR File: A New Formatfor Electronic Data Transfer and Archiving. J.Chem. Inf. Comput. Sci. 1991, 31, 326–333. DOI:10.1021/ci00002a020. (c) Hall, S. R.; Spadaccini, N. The STAR File:Detailed Specifications. J. Chem. Inf.Comput. Sci. 1994, 34, 505–508. DOI:10.1021/ci00019a005. [4] Spek, A. L. PLATON SQUEEZE: A Tool for theCalculation of the Disordered Solvent Contribution to the Calculated StructureFactors. Acta Cryst. 2015, C71, 9–18. DOI:10.1107/S2053229614024929. [5] 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. [6] (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 ScatteringFactors for SHELXL – Model,Implementation and Application. ActaCryst. 2019, A75, 50–62. DOI:10.1107/S2053273318013840. [7] (a) Spek, A. L. Single-CrystalStructure Validation with the Program PLATON.J. Appl. Cryst. 2003, 36, 7–13. DOI: 10.1107/S0021889802022112.(b) Spek, A. L. StructureValidation in Chemical Crystallography. ActaCryst. 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. checkCIFValidation ALERTS: What They Mean and How to Respond. Acta Cryst. 2020, E76, 1–11. DOI: 10.1107/S2056989019016244. 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。 如需PDF文档,请从以下链接下载: 通过网盘分享的文件:晶体数据审稿意见-错用限制指令(PLAT430).pdf
|