A Quasi-Intramolecular Solid-Phase Redox Reaction of Ammonia Ligands and Perchlorate Anion in Diamminesilver(I) Perchlorate
, Istvan E Sajó 5, Imre Miklós Szilágyi 2 and Laszlo Kotai 1,6,*
Round 1
Reviewer 1 Report
When metal complex Ag(NH3)2ClO4 is heated, AgCl remains in the residue after decomposition. Because of the presence of four different chlorine oxoanions (ClOx (x=1~4)) associated with the multivalent nature of chlorine, there are several candidates for the intermediate states that can occur during the decomposition process. The manuscript of the paper entitled “A quasi-intramolecular solid-phase redox reaction of ammonia ligands and perchlorate anion in diamminesilver(I) perchlorate” written by Lara Alexandre Fogaca et al. discusses the results of their investigations for the heat decomposition process using thermal analyses, IR, XRD, and XPS techniques.
This is a relatively long manuscript with 18 pages of printing style text and 11 pages of supplements. It was a little shock for me that the heavy volume paper has a very short introduction consisting of only a few sentences. More surprisingly, the introduction does not mention the chemical reaction involved in the paper’s title at all. For the researchers belonging to the same research field, there might be no need to discuss the background of the study and the universal importance of such pyrolysis reactions. However, there should be few such readers. It would be a duty of author of research papers to explain the purpose of the research so that all readers can quickly understand the content. In addition, such effort will allow the author to polish up their arguments.
In this manuscript, a lot of experimental data were reported. But, these data do not seem to be logically correlated. For example, in the early part of the paper, long discussion has been given for a change of the Raman spectrum due to the phase transition occurring at around 220 K. However, this elaborated discussion using a factor group analysis had virtually nothing to do the thermal decomposition reactions taking place around 200~400C, which would be the main subject of this paper. If the author had tried to write a well-organized introduction, such a logical discontinuity would not occur.
My specialty is molecular solid spectroscopy, thus I am not familiar with the main subject of the paper, i.e. thermal decompositions. So I would like to avoid to evaluate the overall value of the present study. But, if the symmetry analysis presented in the paper is the first report for the phase transition of the compound, I think that the paper would be worth published. However, even in this case, the work should be published as an isolated paper, since the subject is unrelated to the high-temperature decomposition reactions.
As for the Raman study for the phase transition, the author should be advised to polish up the discussion, taking account of the following suggestion. In the present manuscript, the authors discuss the relationship between the local symmetry in the metal complex molecule and the factor group of the crystal using as many as three figures. Since the symmetric change noteworthy in this discussion is associated with the phase transition of the crystal, one should focus on the correlation between the crystal symmetry of the low temperature phase and that of the high temperature, isn’t it?
Besides these problems, there are many simple mistakes in this paper, thereby it seems difficult for the reader to understand the point of the discussion. Some of the obvious issues are listed below, but these are not all. I have to say that this manuscript is incomplete, and has not yet reached the stage of peer review. It should be submitted after polishing up the discussion more carefully.
p1
line 20 “Compound 1” has not been defined at the position.
line 31 “18vibrational spectroscopy”
line 38 [5-9,31][31]: duplicated citation
line 39 Which is compound 1? Mn or Cl? Must be uniquely specified.
p2
line 46 “(Ag(NH3)2(H2O)]ClO4” ( -> [
Figure 1. Figure legend is missing. Cannot distinguish red and blue curves.
p3
line 83, 84, [3+0], [2+1] Meaning of the parentheses is not defined. Jargons should be avoided.
line 89 “[Ag(NH_3)_2]+” ‘+’ should be in upper case. There are numerous similar mistakes.
line 95 “hydrated diamminesilver(I) perchlorate” Should be written in chemical formula or represented with the number such as Compound X. Expressions of compound’s names should be unified in a paper.
p4, 5
Crystal structures should be shown. Only from the information of space group, one cannot guess how many crystallographycally inequivalent molecules exist in the unit cell.
The common names (nu_1~nu_4) appear in Figure 3 and in Figure 4. Are they the same vibrational modes?
p6
Line 150 The sentence “Siliver cations, .....” is unreadable.
Line 159 “IR and Raman 139 spectra”
Line 160 M-1, O-1 are not defined
Line 169 “The band system....” No experimental data is shown.
p7 Infrared data for 1-O and 1-M are not shown.
p11
line 299 “because silver chloride melts at 452C (Figure 6)” Figure 6 is room- and low-temperature Raman data.
p13
line 365 “the peak intensities of silver perchlorate monohydrate increased, whereas ...” It seems the data shows opposite tendency.
p16
line 473 “For research articles with several authors....” should be removed.
Author Response
Reviewer 1:
This is a relatively long manuscript with 18 pages of printing style text and 11 pages of supplements. It was a little shock for me that the heavy volume paper has a very short introduction consisting of only a few sentences.
In order to addres this issue, we added more text into the intro.
More surprisingly, the introduction does not mention the chemical reaction involved in the paper’s title at all. For the researchers belonging to the same research field, there might be no need to discuss the background of the study and the universal importance of such pyrolysis reactions. However, there should be few such readers. It would be a duty of author of research papers to explain the purpose of the research so that all readers can quickly understand the content. In addition, such effort will allow the author to polish up their arguments.
The reviewer is right, but these reactions are new. Thus, we could not tell about them anything before showing our results. In order to addres this issue, we added further information to last sentence of the intro: Based on these results, we propose the possibility of solid-phase quasi-intermolecular redox reactions, between ammonia ligand and perchlorate anion.
In this manuscript, a lot of experimental data were reported. But, these data do not seem to be logically correlated. For example, in the early part of the paper, long discussion has been given for a change of the Raman spectrum due to the phase transition occurring at around 220 K. However, this elaborated discussion using a factor group analysis had virtually nothing to do the thermal decomposition reactions taking place around 200~400C, which would be the main subject of this paper.
The polymorphs of the compound have been known, but the spectroscopic properties of the low-temp. polymorph and the phase change enthalpy has not been studied yet. Therefore, we showed the characteristics of the phase transition and the Raman spectroscopic properties of this low-temperature polymorph – comparing that with the Raman results given for high-temperature polymorph. We also performed factor group analysis of the low- and high temperature polymorphs in order to properly assign the FTIR and Raman data. Following the reviewer’s suggestions, we entered new subtitles.
But, if the symmetry analysis presented in the paper is the first report for the phase transition of the compound, I think that the paper would be worth published. However, even in this case, the work should be published as an isolated paper, since the subject is unrelated to the high-temperature decomposition reactions.
The factor group analysis is new and we think it belongs to this paper because it is essential to properly assign the FTIR and Raman data of the two polymorphs.
As for the Raman study for the phase transition, the author should be advised to polish up the discussion, taking account of the following suggestion. In the present manuscript, the authors discuss the relationship between the local symmetry in the metal complex molecule and the factor group of the crystal using as many as three figures. Since the symmetric change noteworthy in this discussion is associated with the phase transition of the crystal, one should focus on the correlation between the crystal symmetry of the low temperature phase and that of the high temperature, isn’t it?
Yes, it is.
p1 line 20 “Compound 1” has not been defined at the position.
The reviewer is right. It has been revised.
line 31 “18vibrational spectroscopy”
line 38 [5-9,31][31]: duplicated citation
It has been revised.
line 39 Which is compound 1? Mn or Cl? Must be uniquely specified.
It has been revised. This is a general sentence about studying these compounds, and in the next sentence we clarify, that in this paper we deal with only compound 1 (X=Cl).
p2 line 46 “(Ag(NH3)2(H2O)]ClO4” ( -> [
It has been revised.
Figure 1. Figure legend is missing. Cannot distinguish red and blue curves.
It has been revised.
p3 line 83, 84, [3+0], [2+1] Meaning of the parentheses is not defined. Jargons should be avoided.
In order to address the reviewer’s issue we added explaining.
line 89 “[Ag(NH_3)_2]+” ‘+’ should be in upper case. There are numerous similar mistakes.
It has been revised.
line 95 “hydrated diamminesilver(I) perchlorate” Should be written in chemical formula or represented with the number such as Compound X. Expressions of compound’s names should be unified in a paper.
It has been revised.
p 4, 5 – Crystal structures should be shown. Only from the information of space group, one cannot guess how many crystallographycally inequivalent molecules exist in the unit cell
The reviewer is right. The number of crystallographical non-equivalent molecules are given in the text..
The common names (nu_1~nu_4) appear in Figure 3 and in Figure 4. Are they the same vibrational modes?
These vibrational modes are not the same. They are the components of the tetrahedral modes, which arise after the splitting of the “local symmetry group” and the factor-group (f-g). As a rule the same designation of the modes is always used for the components originating from these modes. The explanations of these modes are given in the text.
p6
Line 150 The sentence “Siliver cations, .....” is unreadable.
It can be read in our (downloaded from the “Inorganics” website) version.
Line 159 “IR and Raman 139 spectra”
It has been revised.
Line 160 M-1, O-1 are not defined
These labels have been defined in the introduction and above this sentence in the figure caption.
Line 169 “The band system....” No experimental data is shown.
The experimental data can be seen in the supplementary information as that is given after this sentence.
p7 Infrared data for 1-O and 1-M are not shown.
IR data can be seen for 1-O in Table at p.7, in the first column. The text has been changed.
p11
line 299 “because silver chloride melts at 452C (Figure 6)” Figure 6 is room- and low-temperature Raman data.
The reviewer is right, the supplementary Figure (S6) is the correct. It has been revised.
p13
line 365 “the peak intensities of silver perchlorate monohydrate increased, whereas ...” It seems the data shows opposite tendency.
Yes, the three diffractograms were not normalized, therefore could show the effect correctly. After normalization of AgCl peaks, the real intesntiy ratios can be seen. The figure has been
p16 line 473 “For research articles with several authors....” should be removed.
It has been revised.
Reviewer 2 Report
This manuscript presents a series of high-quality powder-diffraction, gravimetric and spectroscopic measurements on diammine silver(I) perchlorate. It is a thorough, classic study contributing in-depth characterization to the scientific record. Overall, it is well suited for publication in Inorganics.
The authors should carefully re-read and check their manuscript.
As an example, 'assignment' is preferable to 'assignation'
On p.6, line 175 the units for the values in () should be given.
The DSC data in Fig. S1 do not appear to be to a precision of 0.1 K, the temperature of the phase transition should be rounded to reflect the data.
Could some of the shoulders in the low-temperature Raman spectra be due to isotopomers (35Cl and 37Cl), instead of effects due to the phase transition?
Author Response
- As an example, 'assignment' is preferable to 'assignation'
I agree that assignment is better than assignation.
- On p.6, line 175 the units for the values in () should be given.
It has been revised.
- The DSC data in Fig. S1 do not appear to be to a precision of 0.1 K, the temperature of the phase transition should be rounded to reflect the data.
It has been revised
- Could some of the shoulders in the low-temperature Raman spectra be due to isotopomers (35Cl and 37Cl), instead of effects due to the phase transition?
The reviewer is right. It is a possibility, we inserted it into the text
Reviewer 3 Report
In this manuscript, authors corroborated that the reaction of ammoniacal AgNO3 solution or [Ag(NH3)2]NO3 with aqueous solution of NaClO4 only formed [Ag(NH3)2]ClO4, without [Ag(NH3)2]ClO4.H2O reported previously, because the hydration of the diamminesilver(I) cation couldn’t be expected based on thermochemical considerations. Authors also further explored the spectroscopies of [Ag(NH3)2]ClO4, such as IR, Raman and UV and all vibrations were assigned. In addition, thermal decomposition of [Ag(NH3)2]ClO4 was investigated to unveil reaction mechanism and intermediates were analyzed by IR, XPS and titrimetric methods to confirm the formation of silver chlorite and chlorate. This work is very basic study, it is certain significant and of partial interest. I would like to recommend this manuscript for consideration to accept for publication in Inorganics after major revision.
1. Introduction is too short. This section must be improved.
2.The order of references cited is too mess. Authors must reorganized the order of references in manuscript as [1], [2]…
3. In Figure 1, no any label showed what did the red and blue curve represent?
4. In Figure 3-5, although authors wanted to explain the vibration modes of perchlorate anion, ammonia ligand and silver in polymorphs of [Ag(NH3)2]ClO4, it is difficult to understand for a general reader in chemistry. Is it possible to provide a simple method and let reader understand what are A’, A’’, Ag, Bg, Au, Bu etc.?
5. Subscript of some formulas in manuscript need to be corrected.
Author Response
Reviewer 3:
- Introduction is too short. This section must be improved.
Please see our answer to reviewer 1.
2.The order of references cited is too mess. Authors must reorganized the order of references in manuscript as [1], [2]…
It has been done.
- In Figure 1, no any label showed what did the red and blue curve represent?
It has been revised
- In Figure 3-5, although authors wanted to explain the vibration modes of perchlorate anion, ammonia ligand and silver in polymorphs of [Ag(NH3)2]ClO4, it is difficult to understand for a general reader in chemistry. Is it possible to provide a simple method and let reader understand what are A’, A’’, Ag, Bg, Au, Bu?
These are the common group theory symbols. However, some pieces of information regarding to their meaning which are the most important to understand this paper (e,g type of degeneration) have been inserted into the text.
- Subscript of some formulas in manuscript need to be corrected.
These have been done.
Reviewer 4 Report
The authors present a careful study on the quasi-intramolecular solid-phase redox reaction of ammonia ions and ClO4- anion in diamminesilver(I) perchlorate. The authors performed detailed spectroscopic analyses (e.g. corrrelation analysis, IR, UV, Raman). The temperature and enthalpy of phase change for the title compound were determined. It was observed that the thermal decomposition of [Ag(NH3)2]ClO4 undergoes a solid-pase quasi-intramolecular redox reaction. The solid phase AgCl-AgClO4 mixture eutectically melts and the resulting AgClO4 deecomposes in this melt into AgCl and O2. The final decomposition products were detected by IR, XPS and titrimetric methods.
I rfecommend acceptance of the manuscript after taking into account the very minor comment:
references numbers should be given in order of appearance in the manuscript.
Author Response
References numbers should be given in order of appearance in the manuscript.
We corrected these reference numbers.
Round 2
Reviewer 1 Report
I made several comments in the last peer review report. In particular, the introduction in the first manuscript was too short and the scope and purpose of the research were unclear, which was a major problem, I think. In this revision of the manuscript, the authors have expanded the introduction to make it easier to understand the contents of the paper. The improvement seems to be effective. To the other comments, the authors have also made corrections in the revised manuscript. I suppose that the manuscript is now ready to be opened to the public as an academic paper.
Reviewer 3 Report
Based on revised manuscript, I would like to recommend this manuscript for publication in Inorganics.
