N-Heterocyclic Carbene Gold Complexes Active in Hydroamination and Hydration of Alkynes

Round 1

Reviewer 1 Report

There is no doubt that this is a sound review. The language is easy to understand and the paragraphs are well organized. Most of the examples in this paper are from representative literature, which can benefit readers. However, in the conclusion, the authors should use more sentences to forecast the application potential of these type complexes. Whatever, I think this review meets the publication requirements of the journal.

Author Response

Authors thank the reviewer for comments. According to the suggestion, we revised the conclusions by adding some sentences.

Despite all these studies, there is still work to be done, for example 1-achieving low loadings catalytic NHC systems; 2-enhancing the catalytic activity of gold catalysts turned on by ligands and counter anions. Furthermore, given the interesting results obtained by NHC Au(III) complexes in hydroamination reactions, it is also possible to imagine that new higher performing gold (III) complexes will be designed and tested in these and other types of reactions.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper submitted by A. Mariconda et al. is a review of literature covering the period 2007-2022, on the application of NHC gold (I/III) complexes in the proces of hydroamination and hydration of terminal and internal alkynes. Although the concept of the paper is very interesting and the contents fill the gap in literature, I have many reservations as to the way of presentation. My comments and suggestions for the authors are given below. 

1. The presentation of tables should be uniformized to make them clear and understandable. For instance:

- Table 1 – no conditions of the reaction are given in the reaction schema,

- Table 2 – no data on the molar ratio of reagents and catalyst concentration,
- Table 3 –no molar ratio of reagents,  
- Tables 4-7  – in the tables the authors gave conversion, while in the legend is yield,
- Table 8 – both reactions could be presented in one schema, the more so that the reaction conditions are the same, in the legend there is no information on the index b used for description of conversion,
- Table 9 – no schema of reaction, no reaction conditions, no information on index b,
- Table 10 – in the column “yield’ there is no b index, although it is described in the legend,
- Table 11, Table 14 – should be “phenylacetylene” instead of “phenylacetilene”
- Table 17 – incomprehensible result in the column “yield” , entry 196.

 

2. In the Tables giving data on conversion instead of yield, it would be worthwhile to mention the selectivity of the process. It is important as it indicates the amount of the formed by-products.

3. Incomprehensible relation to complexes  4, 5 and 7 in lines 175-177  as they are not mentioned in the paper cited at this place.

 

4. Another difficulty in reading is the number of paragraphs. Usually it is suggested that subsequent paragraphs should be devoted to separate problems, and they should not divide (sometimes at a few points) the information on one problem (one paper), e.g. lines 288 and 289.

 

 

5. I assume that formatting can be improved. For example, Scheme 10 and Fig. 10 should be enlarged for better readability.

 

 

 

6. Very short texts describing the contents of Ref. 17 (lines 131-133).  The authors should give more accurate results to illustrate the advantages of the method described. I mean for instance some results for complexes 4-7, the type of substrates studied.

7. Line 145: complex 8 instead of complex 1 (?)

8. The data presented at some places are difficult to comprehend because there are reaction schemas to illustrate the point. In my opinion, such schemas should be given close to the text referring to them. It really make more sense to present them than to refer the reader to some other fragment or literature. For example, in Table 21 they referred the reader to the structure from Figure 1, etc. Each reaction was run in different conditions that should be described, e.g. above and below the arrow.   

9. In line 590 the authors mention Table 20 that is in line 637 (seems illogical)

10. Minor comments:

- Erroneous numbering of schemas, schema 12 is referred to as schema 8,

- Erroneous numbering of some tables, e.g. Table 15 is referred to as Table 145, while Table 14 – as Table 134,

- In scheme 3, under the arrow the catalyst should be specified by number (cat. 1), and its concentrations should be given in parentheses,

- I would recommend numbering subsequent entries in tables starting from number 1. Each Table presents separate set of results, so continuation of numbering in a few tables is hard to understand.

- apply a uniform way of inserting references in the text, sometimes it is given after the authors’ names , sometimes after year, e.g. 180 vs 186,

- There are many typos and misspellings in the manuscript. Therefore, please use a spell-checker on the revised manuscript before submission.

Because of the above-mentioned comments, this manuscript should be published after major revision.

 

 

 

 

Author Response

We thank the Reviewer. The useful comments and suggestions were taken into consideration and the manuscript has been revised according to the criticisms of the reviewer.

1-All tables have been standardised and correct as suggested by the reviewer. The reaction conditions have been added below each table or in the reaction schemes.

2-The data have been completed when they were available in the reference paper.

3- The mistake was corrected.

4-We have revised this aspect.

5-We tried to improve the formatting.

6-We have included further details of the work.

7-The mistake was corrected.

8-We agree with the reviewer, but reporting the same figures several times would make the paper very heavy. The choice made requires only a little extra effort from the reader, making the paper more light.

9-Correct with table 18.

10-All the suggestions (minor comments) underlined by the reviewer were taken into account and the required changes have been made.

Author Response File: Author Response.pdf