Peroxidative Oxidation of Cyclohexane Using 3d Metal Complexes with Hydrazone-Derived Ligands as Catalysts: Exploring (Un)Conventional Conditions
, Beatriz P. Nobre 1, Atash V. Gurbanov 1,2, António M. F. Palavra 1, M. Fátima C. Guedes da Silva 1,3, Kamran T. Mahmudov 1,2 and Armando J. L. Pombeiro 1,4,*
Round 1
Reviewer 1 Report
The paper is an interesting contribution to the oxidation processes of alkenes despite the results obtained being not as good as the best previously published. The paper is well made and the English language is of good level. Some minor additions are: On page 7, a scheme showing the proposed reaction mechanism, which was described at the bottom of the page, should be included. Also, the results discussed in section 2.3 should be summarized in a table, which facilitates certainly their understanding. The discussion of the data in this section should be also adapted to the table. On page 10, in file 317, the number of complexes should be in bold.
Author Response
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Author Response.docx
Reviewer 2 Report
The article by Pombeiro et al. deals with the catalytic reaction of alkanes into functional derivatives. The topic of C-H functionalisation is quite a rapidly developing one and is interesting from the point of view of practical applications. This work is a continuation of the oxidation of cycloalkanes, including new complexes and reaction conditions. From the readers' point of view, the authors should answer some questions, possibly improving the susceptibility to the material.
Comment 1. It is good that the authors have compared different transition metal complexes. However, the choice of zinc in this series is questionable. Can zinc(II) promote reactions with hydrogen peroxide?
Comment 2. How does the structure of the ligand affect the catalytic properties of the copper complexes? At first sight, under acidic conditions these complexes should undergo a decomposition. In the section comparing the catalytic activity of different copper complexes it would be interesting to analyze depending on the coordination environment of the metal ions. For example, the influence of the nature of the ligands (carboxylates, enamines, etc.), the presence of a hydroxy/oxy cluster framework.
Comment 3. The cited literature is mainly the work of the authors themselves. Publications of other research groups (https://doi.org/10.3390/molecules27238505, https://doi.org/10.1002/ejic.201901052) would be good to cite.
Comment 4. What happens to the catalyst under oxidation conditions? It would be good to describe the observed processes visually (colour change, heterogeneity).
Author Response
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Author Response File: Author Response.docx
