6-Amino-3-(prop-2-en-1-yl)-9H-purin-3-ium Tetracopper(I) Hexabromide: Synthesis and X-ray Structure Determination
Round 1
Reviewer 1 Report
The paper is written well. In my opinion, the study is adequate to the scope of the journal. Structural analysis is presented reliably. I recommend the work to publish in Molbank.
Author Response
The authors are thankful to Reviewer #1 for the favorable review and his approval of the manuscript for publication.
Reviewer 2 Report
The submitted study is clear, concise and provides the method of synthesis, crystal structure and Raman spectroscopic characterization of the new Cu(I) complex. Therefore it meets the criteria of Molbank. I have, however, some ideas that should help the Authors improve their article.
In the introduction it could be mentioned that it was possible for both N(1) and N(2) to act as a Lewis base and form a bond with Cu(I). For example, in similar structure with Co(III), the bond between the metal cation and N is being formed with the N(2) (CCDC refcode: ACNTCC).
{Cu2Br6} is a quite common motif in the reported crystal structures (more than 150 crystal structures reported in CCDC). Can the Authors comment on the structure of this part of the complex in the different crystals and compare it with their one. I.e. the coordination number, lengths, angles.
Supplementary materials: It should not be “Raman spectra” but “Raman spectrum”.
Author Response
We are grateful to Reviewer #2 for the favorable and supportive review. We have addressed the comments as mentioned below:
“1) In the introduction it could be mentioned that it was possible for both N(1) and N(2) to act as a Lewis base and form a bond with Cu(I). For example, in similar structure with Co(III),the bond between the metal cation and N is being formed the N(2) (CCDC refcode: ACNTCC).”
Response: Introduction part now is improved according to the Reviewer suggestions.
“2) {Cu2Br6} is a quite common motif in the reported crystal structures (more than 150 crystal structures reported in CCDC). Can the Authors comment on the structure of this part of the complex in the different crystals and compare it with their one. I.e. the coordination number, lengths, angles.”
Response: The deeper discussion on structural motifs was implemented to the paper.
“3) Supplementary materials: It should not be “Raman spectra” but “Raman spectrum””.
Response: Now this was corrected.
All changes in the manuscript are marked in green.
Reviewer 3 Report
This paper by Slyvka et al. concerns the crystal structure of a tetracopper(I) hexabromide core bearing two adenine derivatives as a ligand. The title copper complex was characterized by X-ray crystallography and Raman spectroscopy. However, the paper cannot be published in its present form, and a major revision is needed.
1) A comment concerning the product yield for complex 1 is missing in the main text, Scheme 1, and the experimental section.
2) The authors could characterize the complex 1 by X-ray crystallography, while no evidence of the purity of 1 is mentioned in the paper. This may also be why the authors did not provide any elemental analysis for 1.
3) Despite measuring the Raman spectrum for 1, there was no discussion of the observed peaks. The authors should be discussed the assignment and comparison with a free adenine ligand.
4) Have the authors tried the Energy framework analysis? Energy framework analysis may give many readers a more comprehensive understanding of energy values.
5) For the crystal structure in Figure 1, it is better to use ORTEP, which gives a visual indication of the degree of thermal ellipsoids, than a ball-and-stick diagram.
6) In Scheme 1, the structural formula for 1 should be rewritten to show the coordination environment around the copper atoms. Additionally, ‘e-‘ above the arrow in Scheme 1 should be eliminated.
Author Response
We are grateful to Reviewer #3 for the favorable and supportive review. We have addressed the comments as mentioned below:
“1) A comment concerning the product yield for complex 1 is missing in the main text, Scheme 1, and the experimental section. ”
“2) The authors could characterize the complex 1 by X-ray crystallography, while no evidence of the purity of 1 is mentioned in the paper. This may also be why the authors did not provide any elemental analysis for 1. ”
Response: We succeeded to obtain only very small amount (to be exact, few crystals) of the crystals of the title compounds. Such an amount of the compound was not enough for us to perform elemental analysis. Concerning the purity of studied complex, we checked most found crystals by diffraction technique and found them in accordance to 1. No other compounds were found on the electrode surface.
“3) Despite measuring the Raman spectrum for 1, there was no discussion of the observed peaks. The authors should be discussed the assignment and comparison with a free adenine ligand. ”
Response: The band assignment in the Raman spectrum of 1 now is presented in Supplementary Materials. It is based on the Raman spectra of adenine and other ally derived heterocycles found in the literature.
“4) Have the authors tried the Energy framework analysis? Energy framework analysis may give many readers a more comprehensive understanding of energy values. ”
Response: Energy framework calculations have not been performed for 1. His addition to the topological analysis of the structure and the geometric description of weak interactions (both are given in the text of the article), in our opinion, could complicate the perception of the compound description.
“5) For the crystal structure in Figure 1, it is better to use ORTEP, which gives a visual indication of the degree of thermal ellipsoids, than a ball-and-stick diagram.”
Response: Figure 1 was improved providing thermal ellipsoids for atoms.
“6) In Scheme 1, the structural formula for 1 should be rewritten to show the coordination environment around the copper atoms. Additionally, ‘e-‘ above the arrow in Scheme 1 should be eliminated. ”
Response: Now the structure formula in Scheme 1 is rewritten according to the Reviewer suggestions.
All changes in the manuscript are marked in green.
Round 2
Reviewer 3 Report
The manuscript has been revised in accordance with the comments, and I think it can be accepted for publication in Molbank.
