之前的文章中已经详细介绍了单晶衍射实验部分如何详细描述《正文中如何写单晶衍射试验内容》，但是对精修部分描述较少。这次将仔细介绍单晶结构精修部分如何详细撰写。
![]()
The space group P212121 was determined by Olex2(Dolomanov, 2009). The structure was solved by the ShelXT (Sheldrick, 2015) structure solution program using intrinsic phasing methods. All non-hydrogen atoms were determined directly by ShelXT and refined by Least Squares using version 2018/3 of ShelXL (Sheldrick, 2015). 首先描述精修使用的软件。本例中采用OLEX2软件确定空间群为P212121，采用ShelXT中的本征相位法进行粗解，然后采用ShelXL中的最小二乘法进行精修。All non-hydrogen atoms were refined anisotropically. The tert butyl at the end of the molecule has undergone disorderly refinement with PART instruction. The occupancies was refined freely and the final occupancies were about 0.4:0.6. Some instructions (SIMU and DFIX) were performed to get a better model for tert butyl. From the perspective of temperature factors, some free solvents are clearly not fully occupied, so their occupancies are freely refined.然后描述非氢原子的精修方式，包括用到的指令和占有率处理等信息。所有非氢原子均采用各向异性进行精修。末端的叔丁基使用PART指令采取了无序精修。叔丁基占有率采用自由变量精修，最终占有率约为0.4:0.6。为了得到更好的叔丁基模型，采用了SIMU和DFIX指令进行精修。对于一些游离的溶剂分子，其温度因子偏大，因此对其占有率进行了无序精修。The positions of hydrogen atoms on carbon atoms were calculated geometrically and refined using the riding model. Their coordinates and displacement parameters were constrained to ride on the carrier atom [C-H = 0.97 Å and Uiso(H) =1.2Ueq(C) for alkyl H atoms, C-H = 0.93 Å and Uiso(H) =1.2Ueq(C) for aromatic H atoms.再然后描述碳原子上的氢原子的处理方式。碳原子上的氢位置均是通过理论计算得到，并采用骑式模型进行精修。氢原子被约束在其相连的碳原子上，其键长和温度因子也需详细描述。All the hydrogen atoms on oxygen atoms were located from difference Fourier map inspection and freely refined with Uiso(H) = 1.5Ueq(O). The distance between the hydrogen atom and the oxygen atom were restrained to 0.85 Å for hydroxyl and water molecules.再然后描述活泼氢的处理方式。同碳原子上的氢不同，活泼氢一般采用自由精修的方式，并且其占有率被指定为相连原子的1.5倍。活泼氢和相连的原子距离一般被限制为0.85Å。The structure contained large void, and the solvent and the positive or negative ions located in the void couldn’t be identified because it was highly disordered had so small residual peak.Therefore, SQUEEZE in PLATON program was performed to remove the highly disordered solvent and ions. The numbers of masked ions and solvent molecules were confirmed by TG analysis. After calculation, the ions and solvent molecules were added in the _chemical_formula_moiety,_chemical_formula_sum and other relative items.结构中如果有很大的孔洞，且其中的溶剂无法被指认出，就需要采用溶剂掩膜。该例中使用了PLATON中的SQUEEZE进行操作。还需对其中的溶剂分子采用其他方法进行确证，该例中采用了热重的方法。最后还需要对cif中相关的项进行更新，将溶剂的信息加到其中。Finally, inverted twins were discovered and BASF/TWIN instructions were used for refinement.最后还发现该例为倒反孪晶，采用BASF/TWIN 对倒反孪晶进行了精修。![]()
本公众号永远免费且无任何广告。
如需软件下载请去qq群。
如需交流可加公众号微信进微信群：dayouzidanjin
或者qq群：653906413
目前微信一群已满，有兴趣可加二群。
