【关键词】高估占有率
【审稿意见】
Structure 2:
Atom naming is completely meaningless.Meaningless disorder refinement for tBu group of COAA and C01E. Cl04 carries a huge negative density, refines to only 65-70% of a chlorine.Large, well resolved difference densities were squeezed (the largest nearly 5 electrons). The occupancies of the “Ni” and “Co”refine to 97% and 97.5%. 97% of 28 electrons (Ni) is 27 electrons (Co).This could easily be two Co atoms.The proton at the coordinated methanol is missing.It is visible in difference density maps. As refined there are five negative charges (6 if the“methanolate”is counted). Based on bond valence sums the cations are trivalent.Structure 3:
Atom naming is completely meaningless.Large, well resolved difference densities were squeezed (the largest 4 electrons).The disorder refinement is meaningless.The minor CF3 group has a CF3 cyclobutane with F-F bonds of 1.5 Angstroms. Some completely new “halogen bonding”?The second water H atom was refined as half occupied. It is in H-bonding distance to either the SO3 group or to (squeezed) Q4 (an interstitial water molecule)The verification reply for the structure is nonsense. It just proofs that the refinement is insufficient.【分析回复】
在结构2中,审稿人指出原子命名是完全没有意义的。叔丁基上的COAA和C01E的无序精修是没有意义的。Cl04具有巨大的负密度,占有率仅能精修为65-70%。大的、分辨良好的电子密度被SQUEEZE掉了(最大的将近5个电子)。“Ni”和“Co”的占有率可以分别精修到97%和97.5%。28个电子(Ni)的97%是27个电子(Co)。这很容易是两个钴原子,而不是一个Ni和一个Co。配位甲醇处的质子缺失。它在差值电子密度图中可见。精修后有五个负电荷(如果计算“甲醇盐”,则为6个)。根据键价和,阳离子是三价的。结构3中,审稿人指出的问题类似。命名无意义;大的、分辨良好的电子密度被SQUEEZE掉了;无序精修无意义。审稿人一针见血地指出该结构的验证回复是无稽之谈,这恰恰证明了精修是不够的。综上可见审稿人对这精修的结果多失望。命名的问题容易更改,只要将原子重新按顺序命名即可。无序的问题也好修改,只要加上一些距离的限制让键长合理即可。SQUEEZE的问题也好解决,只要把那些电子密度指认了即可,6左右的密度一般是水分子。最不好解决的而且大家不常关注的是审稿人提出的Ni和Co占有率的问题。审稿人说占有率可以精修到97%和97.5%,并不是指的是占有率真的是97%,而是在这个位置上原子可能偏重,可能和一个较轻的原子共同占据这一位置。在这个结构里,重点需要区分哪个是Co哪个是Ni。Co和Ni在元素周期表上很接近,通过单晶衍射不好区分。加上该结构是对称的,单独将一个原子定成Ni另个原子定成Co是不合适的,需要将Co和Ni采取共占据精修才能得到合适的结果。
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