5,5′-Thiobis(4-chloro-3H-1,2-dithiole-3-thione)

Round 1

Reviewer 1 Report

Overall, this manuscript has been clearly and carefully written. The English language is very good.  I have some suggestions that I believe would enhance its impact. I think that the paper should be published after these comments have been addressed.

[1] Line 22 change to "1,3-dipolar cycloadditions"

[2] Line 31 change to "In an attempt to obtain thiocyanate..." This change is necessary because the thiocyanate was not in fact obtained.

[3] Line 39 change "also occurred" to "was observed"

[4] The reference for compound 1 does not give data for this compound. The current manuscript would be significantly enhanced if it also reported data for this compound. The authors have worked extensively with 1 and it is about time that its full data were recorded so that it is easily accessible to others.

[5] Line 45 and 46, the authors say "apparently due to its further transformations at elevated temperature" Since compound 3 is not detected they have no real evidence of its formation and subsequent decomposition. There could be other explanations for the decomposition seen here.

[6] My biggest issue with this manuscript was the presentation and discussion of the possible mechanism for the formation of the dimer. Firstly, what is presented is a partial incomplete hypothesis for the mechanism. The authors should show a complete proposal for the mechanistic course of the reaction. For instance, what is the nucleophile? They should also clearly state that it is hypothetical as no work has been done to support the hypothesis. This is particularly important because it is not at all clear to me whether this process is likely to be a single electron or two electron process. Secondly, ref 9 refers to a very different reaction (Pd and SmI2 catalysed) that quite probably occurs through single electron transfer mechanisms so it is not very relevant to the current mechanistic discussion. Furthermore, ref 9 actually contains two interesting observations; namely, that the reaction does not occur without the catalyst and that there is no reaction in THF at reflux. Thus, I would like to see the section on the mechanism improved a little before publication.

[7] Line 63, based on my comment above, I would change "nucleophilic substitution of" to "reaction of"

Author Response

Reviewer 1

The authors are grateful to the reviewer for a kind and highly professional review.

Point 1.

Line 22 change to "1,3-dipolar cycloadditions"

Response from authors.

Corrected as suggested by the reviewer.

Point 2.

Line 31 change to "In an attempt to obtain thiocyanate..." This change is necessary because the thiocyanate was not in fact obtained.

Response from authors.

Corrected as suggested by the reviewer.

Point 3.

Line 39 change "also occurred" to "was observed"

Response from authors.

Corrected as suggested by the reviewer.

Point 4.

The reference for compound 1 does not give data for this compound. The current manuscript would be significantly enhanced if it also reported data for this compound. The authors have worked extensively with 1 and it is about time that its full data were recorded so that it is easily accessible to others.

Response from authors.

The required data were added to the paper.

Point 5.

Line 45 and 46, the authors say "apparently due to its further transformations at elevated temperature" Since compound 3 is not detected they have no real evidence of its formation and subsequent decomposition. There could be other explanations for the decomposition seen here.

Response from authors.

The explanation for the decomposition of the thiocyanate derivative 3 has been removed.

Point 6.

My biggest issue with this manuscript was the presentation and discussion of the possible mechanism for the formation of the dimer. Firstly, what is presented is a partial incomplete hypothesis for the mechanism. The authors should show a complete proposal for the mechanistic course of the reaction. For instance, what is the nucleophile? They should also clearly state that it is hypothetical as no work has been done to support the hypothesis. This is particularly important because it is not at all clear to me whether this process is likely to be a single electron or two electron process. Secondly, ref 9 refers to a very different reaction (Pd and SmI2 catalysed) that quite probably occurs through single electron transfer mechanisms so it is not very relevant to the current mechanistic discussion. Furthermore, ref 9 actually contains two interesting observations; namely, that the reaction does not occur without the catalyst and that there is no reaction in THF at reflux. Thus, I would like to see the section on the mechanism improved a little before publication.

Response from authors.

The part of the paper related to the mechanism of the described reaction has been completely revised. Scheme 2 has been removed from the paper.

Point 7.

Line 63, based on my comment above, I would change "nucleophilic substitution of" to "reaction of"

Response from authors.

Corrected as suggested by the reviewer.