晶体数据审稿意见-R因子高以及无序建模

DJ_Tokyo

★声明：本文仅代表个人观点，笔者学识有限，资料整理过程中难免存在疏漏谬误，请不吝指正。

晶体数据审稿意见-R因子高以及无序建模

案例来源：CCDC [1]: 2416519. DOI [2]:10.5517/ccdc.csd.cc2m3l7l. (Acta Cryst. 2025, C81, 82–92.DOI: 10.1107/S2053229625000282.)

案例结构如图1所示（由ChemBioDraw [3]绘制）。

▲图1 案例结构

审稿意见：

a)The R factors for compound 1 are much higher than is normally expectedfor a paper in this journal. The refinements show some features that give riseto suspicion: Fo2 > Fc2 for most of the reflections ofmedium or weak intensity; large K values for weak reflections; Rinta little larger than one would expect for an uncomplicated structure with agood crystal; R factors higher than expected given Rint.These issues usually point towards a twinned crystal, but I have been unable tofind a twin law to suggest; I've examined twinned possibilities for each of thethree Pca21 space group possibilities suggested by shelxt,but none of them seem to look promising.

b)In 1, the displacement parameters for C6-C10 are much higher thanelsewhere in the molecule. Shelxl suggests splitting these atoms, and when Idid so, I got a refinable cyclopentadienyl group nicely disordered betweeneclipsed and staggered orientations. This did not solve the R-factor problem,but I would suggest that the authors check out disorder possibilities insubmitting an amended paper.

大意

a）化合物1的R因子远高于本期刊论文正常预期。精修显示了一些令人怀疑的特征：对于大多数中等或弱强度衍射点，Fo2 > Fc2；弱衍射点的K值较大；Rint比人们预期的具有良好晶体的简单结构要大一点；考虑到Rint，R因子高于预期。这些问题通常指向孪晶，但我无法找到孪晶法则来提出建议；我已经研究了SHELXT [4]提出的三种Pca21空间群可能性中的每一种孪晶可能性，但似乎都没有前景。

b）在化合物1中，C6-C10的位移参数远高于分子中的其他地方。SHELXL [5]建议分裂这些原子，当我这样做的时候，我得到了一个可精修的环戊二烯基，在遮蔽和交错取向之间很好地无序排列。这并没有解决R因子问题，但我建议作者在提交修改后的论文时检查无序的可能性。

如图2所示（由Olex2 [6]呈现），Rint = 5.25%，R1 = 7.28%，wR2 = 15.41%，Rint较低，但R1和wR2较高，此外，C6-C10位移参数大，表现为原子椭球大和拉长（相较于其他原子）。

▲图2 案例结构投稿时状态

如图3所示，对C6-C10做无序处理，R1和wR2稍有降低，但仍然很高。

▲图3 无序处理结果

后来，作者重新培养了新的晶体，重新测试得到新的数据如图4所示，Rint = 3.26%，R1 = 3.34%，wR2 = 9.01%，该数据返稿后顺利接收。

▲图4 案例结构发表时状态

结语

该数据投的是《晶体学报》期刊，本身对晶体数据要求比较高，如果是投一般期刊，一开始的数据大概也能过，但如果遇到专业且要求较高的审稿人，也可能提出相同审稿意见。当初该数据找笔者时，未提供原始衍射照片文件，因此无法确定是否确系孪晶，不过作者用新的晶体测试得到新的数据解决了问题也是一种解决方案。

相关视频：

单晶结构解析练习715(文献案例-无序处理-审稿意见)：https://www.bilibili.com/video/BV1PTBpBhEwQ

如需数据进行练习，请从以下链接下载：

论文PDF+CIF：

链接:https://pan.baidu.com/s/1NS4ReD4-J7H8jDWrROMTGA?pwd=yeye

提取码: yeye

晶体数据：

链接:https://pan.baidu.com/s/1qSBeIJmxcJjttkIFORl6pg?pwd=g6p6

提取码: g6p6

参考文献

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