(η4-Tetraphenylcyclobutadiene)-(η5-pentaphenylcyclopentadienyl)-cobalt
Round 1
Reviewer 1 Report
Very nicely written article about an interesting compound.
Only some very minor comments/remarks
p5 line 139-141:
As a remark, in mercury, it is possible to normalize the hydrogens to make a direct comparison possible (Edit>Normalize Hydrogens ... )
p6 line 168-171
Please be conscience that the reported solvent accessible volume reported here is misleading as the 121A3 is the sum of 8 pockets of 13 - 17A3 , which individually are too small to accommodate any solvent molecules! Please make sure this emerges from the text.
The subroutine of crystalExplorer most likely does not take into account the VdW radius and these two lines are best removed as well as Figure S10
p2 line 46 leads -> lead
Author Response
Only some very minor comments/remarks
p5 line 139-141:
As a remark, in mercury, it is possible to normalize the hydrogens to make a direct comparison possible (Edit>Normalize Hydrogens ... )
RESPONSE: Thank you for the hint. Unfortunately, my license of mercury does not allow the use of this feature…
p6 line 168-171
Please be conscience that the reported solvent accessible volume reported here is misleading as the 121A3 is the sum of 8 pockets of 13 - 17A3 , which individually are too small to accommodate any solvent molecules! Please make sure this emerges from the text.
RESPONSE: Thanks for this hint. I therefore added an explanatory sentence to the text, and also a platon cavity plot to the Supporting Information.
The subroutine of crystalExplorer most likely does not take into account the VdW radius and these two lines are best removed as well as Figure S10
RESPONSE: Since I am not yet an expert for CrystalExplorer (although I am using it quite often) and do not really know how this subroutine works, I followed your suggestion and removed the two lines together with the original Figure S10.
p2 line 46 leads -> lead
RESPONSE: This mistake was corrected.
Reviewer 2 Report
This article reports on the synthesis, spectroscopic analysis, and crystal structure analysis of a complex in which a cobalt atom is sandwiched between cyclobutadiene and cyclopentadienyl rings.
The authors have performed the crystal structure analysis without major problems. The authors discuss the molecular structure and in particular compare the molecular structure in the crystal with several molecules with similar sandwich structures. This is a good point. The steric hindrance of the many phenyl groups attached to the two ring structures and the CH. C interactions, and the results of Hirshfeld analysis are included.
Some comments are given.
1) Examination of the RES file in the CIF afforded shows that 9 reflections have been removed. A clear reason must be given for such an manipulation. When these are analyzed with the reflections included, the R factor becomes larger and residuals are found near the C81-C86 rings. These may suggest a small disturbance of the phenyl group.
(2) The CH.... C interaction (L165), it is necessary to describe what criteria are used to recognize it as an interaction. Also, the light blue line needs to be explained in the caption of Fig.3. I prefer the style of not filling in many interactions in a crystal structure diagram such as Fig.3.
3) The position and volume of the void in the crystal is often of interest. Of crystallographic interest is the calculation and display of the void by Platon or Mercury. If the two types of voids are to be listed together, information on their correspondence is needed.
4) I would like to confirm the number of oxidation number of cobalt atom, which may be neutral, so please add a corresponding statement in the text.
Author Response
Some comments are given.
1) Examination of the RES file in the CIF afforded shows that 9 reflections have been removed. A clear reason must be given for such an manipulation. When these are analyzed with the reflections included, the R factor becomes larger and residuals are found near the C81-C86 rings. These may suggest a small disturbance of the phenyl group.
RESPONSE: These 9 reflections had been removed, because the „checkcif“ routine issued a „919_ALERT_3_B REFLECTION LIKELY AFFECTED BY THE BEAMSTOP“ for 8 of them. Checking the „shelxl.lst“ output showed that 6 of them had negative intensities and two very low intensities, much too low for reflections 1 1 1 and 1 0 3. These low intensities cannot be „real“ and have therefore to be removed from the hkl file. Thus only one reflection is left (0 3 6), that creates a checkcif „934_ALERT_3_C“ due to large discrepancy between Iobs and Icalc. I have no explanation for this deviation, as the Difference Fourier synthesis with inclusion of this reflection does not indicate any systematic omission of electron density- all difference peaks are of low intensity (< 0.3 e/Å3) and are spread over the whole molecule. Maybe this reflection has something to do with the unaccounted voids, but there is no proof for this. Therefore, I left the hkl file, as it was.
(2) The CH.... C interaction (L165), it is necessary to describe what criteria are used to recognize it as an interaction. In addition, the light blue line needs to be explained in the caption of Fig.3. I prefer the style of not filling in many interactions in a crystal structure diagram such as Fig.3.
RESPONSE: I have added details about the criteria, and shifted the explanation for the blue lines from the main text to the Figure caption. I also decided to keep the blue lines in the figure, because this shows how many of these interactions exist!
3) The position and volume of the void in the crystal is often of interest. Of crystallographic interest is the calculation and display of the void by Platon or Mercury. If the two types of voids are to be listed together, information on their correspondence is needed.
RESPONSE: I have removed the two lines corresponding to the CrystalExplorer results and the associated Figure S10. I have added some comments on the platon results and also placed a “platon cavity plot” as new Figure S10 into the Supporting Information..
4) I would like to confirm the number of oxidation number of cobalt atom, which may be neutral, so please add a corresponding statement in the text.
RESPONSE: I have added a statement about the results of a Bond Valence Analysis, together with a caveat.
