Synthetic and Structural Chemistry of Uranyl-Amidoxime Complexes: Technological Implicationsâ€
, Maria Iliopoulou 1, Demetrios I. Tzimopoulos 2 and Spyros P. Perlepes 1,*Round 1
Reviewer 1 Report
This manuscript reviews essentially the synthesis of uranyl-amidoxime complexes that have been characterized by single crystal X-ray diffraction analysis. As seen by the number of publications, wide work has already been performed on the field of uranium extraction from aqueous with amidoxime-based materials.
The authors attempted to obtain clues from the solid-state structure that can contribute to the improvement of the uranium extractants. 95 publications were analyzed to highlight the progress in the field. The work https://doi.org/10.1016/j.ica.2014.06.023 should also be mentioned.
The review was divided into six sections; however the section division must be improved.
The review makes a valuable contribution in the development of this domain; however major revisions are need before acceptance.
Page 1, line 44, I believe that the more recent review DOI:10.1039/c9ta14082d should also be mentioned.
Page 3, line 82: the sentence “in an older” should be removed. The publication is not so older.
Page 3, line 119, the more recent review DOI: 10.1039/d0dt03151h (I am not an author) can also be added after the sentence: “…the development of non-aqueous uranium chemistry [28],”
Page 3, line 149, in the PDF version the eqn. (1) seems to have a problem, some atoms appear as superscript (?)
Page 4, line 177, the references should be cited in the text rather in the title section.
Page 4, line 191, in the legend of Figure 1, replace “amidines” by “amidoxime”
Page 7, line 248, the references should be cited in the text rather in the title section.
Page 9, in order to follow the discussion, it will be better that the numbering of the uranyl complexes follow the order in the text. Example compound 5 should be compound 2.
Page 12, the sub-section 5.1, 5.2 and 5.3 can be emerged in only one section.
Page 13, 14 and 16, check the equations (design).after
Page 16, line 513, after “… converting ligands into IL forms.” a reference should be added.
Page 17, line 545, after “…over Th4+ and Eu3+.” a reference should be added.
Page 17, line 556, move the reference for the end of the sentence.
Page 17, line 562, a reference is missing.
Page 21, the coordination mode illustrated in Figure 22 does not correspond to the one in the complex in Figure 21
Page 23, check equation 8.
Page 24, line 801, remove from the subtitle the sentence “Unpublished results in brief”
Page 24, line 804, “Our results…short overview”. Just mention that since they are unpublished results, it will be discussed briefly, and cite the theses.
Page 28, the discussion in the section 6 should be divided in two parts. First part until the line 923 (
From the line 924 should be the section 6, suggestion for title: Concluding remarks and prospects.
Page 30, line 966, the sentence “Last, but not least, …writing it” should be removed.
Comments for author File: 
Comments.pdf
Author Response
Reviewer 1
This manuscript reviews essentially the synthesis of uranyl-amidoxime complexes that have been characterized by single crystal X-ray diffraction analysis. As seen by the number of publications, wide work has already been performed on the field of uranium extraction from aqueous with amidoxime-based materials.
The authors attempted to obtain clues from the solid-state structure that can contribute to the improvement of the uranium extractants. 95 publications were analyzed to highlight the progress in the field,
Thank you very much for her/his positive evaluation.
The work https://doi.org/10.1016/j.ica.2014.06.023 should also be mentioned.
The comment is correct. We have included the relevant reference (ref. [81]) in the revised ms. The complex described in this paper has been inserted in the discussion (complex 12). As a consequence of this addition, the numbering scheme of the complexes has been changed, e.g., the old compound 12 has now become 13.
The review was divided into six sections; however the section division must be improved.
The section division has improved, please see below.
Page 1, line 44, I believe that the more recent review DOI:10.1039/69ta14032d should also be mentioned.
The comment is correct. The suggested review has been mentioned (ref. [9] in the revised ms). Due to this addition (but also because of other changes −please see below), the numbering scheme of the references has been changed.
Page 3, line 82: the sentence "in an older" should be removed. The publication is not so older.
The correction has been made.
Page 3, line 119, the more recent review DOl: 10.1039/dOdt03151h (I am not an author) can also be added after the sentence: " …the development of non-aqueous uranium chemistry [28],”
The suggested review has been added (ref. [29] in the revised ms).
Page 3, line 149, in the PDF version the eqn. (1) seems to have a problem, some atoms appear as superscript (?)
This is a GENERAL COMMENT for all equations (see also comments below). When we uploaded the original ms, all equations were correct. The observed discrepancies have been derived from the journal’s system, and we are not responsible for this. We apologize to the reviewer. In order to avoid further inconvenience with the ChemDraw equations, we have incorporated the same equations as images in the manuscript.
Page 4, line 177, the references should be cited in the text rather in the title section.
We have removed the references from the section title. The references are now cited in the text of the revised ms.
Page 4, line 191, in the legend of Figure 1, replace "amidines" by "amidoxime"
The mistake in the legend of Figure 1 has been corrected.
Page 7, line 248, the references should be cited in the text rather in the title section.
We have removed the references from the section title. The references are now spread in the text of the revised ms.
Page 9, in order to follow the discussion, it will be better that the numbering of the uranyl complexes follow the order in the text. Example compound 5 should be compound 2.
This is the only point by Reviewer 1 which we have not taken into account. Although we fully respect the reviewer’s opinion, we prefer to retain the numbering scheme as it was in the originally submitted ms. In such a way, the numbering follows the order in Table 1 in which the complexes are grouped according to the ligand used. For example, complexes 1-4 contain the neutral and anionic forms of H2AAO, complexes 5-9 contain the neutral and anionic forms of H2BAO, complexes 17 and 18 (revised numbers) are compounds of the singly and doubly deprotonated forms of H3L3, respectively, and complexes 19 and 20 contain the singly and doubly deprotonated forms of H3L4, respectively. Also, complexes 11 and 12 contain the monoanions of the chemically similar ligands H3A and H3A’. In any case the issue raised by the reviewers concerns only complexes 1-9; the rest of the complexes follow the order both in the text and Table 1. We believe that this numbering scheme is convenient for the readers and we, therefore, asking Reviewer’s 1 indulgence to retain the present scheme.
Page 12, the sub-sections 5.1, 5.2 and 5.3 can be emerged in only one section.
The comment is logical. We have emerged the sub-sections 5.1, 5.2 and 5.3 in only one sub-section (sub-section 5.1 in the revised ms). As a consequence, the numbering of the sub-sections has been changed; for example, the old sub-section 5.4 is sub-section 5.2 in the revised ms and so on.
Page 13, 14 and 16, check the equations (design).
Please, see our answer (general comment concerning the equations) above.
Page 16, line 513, after "…converting ligands into IL forms." a reference should be added.
The appropriate reference (ref. [79] in the revised ms), which existed 13 lines below this point, has been also added at the suggested position.
Page 17, line 545, after"…over Th4+ and Eu3+." a reference should be added.
The appropriate reference (again ref. [79]) has been added at the suggested position in the revised ms.
Page 17, line 556, move the reference for the end of the sentence.
We have moved the reference (ref. [80] in the revised ms) at the end of the sentence.
Page 17, line 562, a reference is missing.
The missing reference (again ref. [80]) has been added at the suggested point.
Page 21, the coordination mode illustrated in Figure 22 does not correspond to the one in the complex in Figure 21
This comment is correct and extremely valuable! We have re-drawn the now correct coordination number in Figure 22, thus avoiding a serious mistake.
Page 23, check equation 8.
Please see our answer (general comment concerning the equations) above.
Page 24, line 801, remove from the subtitle the sentence "Unpublished results in brief"
We have removed from the subtitle the requested sentence.
Page 24, line 804, "Our results…short overview" Just mention that since they are unpublished results, it will be discussed briefly, and cite the theses.
We have exactly followed this suggestion in the revised ms.
Page 28, the discussion in the section 6 should be divided in two parts. First part until the line 923 ( From the line 924 should be the section 6, suggestion for title: Concluding remarks and prospects.
We have divided the discussion in the original section 6 in two parts, as correctly suggested by the reviewer. To avoid confusion, and since the first part concerns a separate issue (which can not be mixed with the sub-section 5.9), the former section 6 has been splitted in two sections in the revised ms. Section 6 has now the title “EXAFS Studies” and Section 7 has now the title “Concluding Remarks and Prospects”.
Page 30, line 966, the sentence "Last, but not least,…writing it" should be removed.
We have removed this sentence in the revised ms.
We are grateful to Reviewer 1 for her/his time to study the ms, and provide us with valuable comments and suggestions. She/he examined the ms line-by-line and all the revision comments were clear and well organized. Her/his contribution to improve the quality of the review is great!
Reviewer 2 Report
Although I’m rather expert for the coordination chemistry of transition metals then f-block elements, I have much appreciated the lecture of this quite comprehensive review article on the coordination chemistry of Uranyl- salts ligated by amidoxime ligands. This well-written and scholarly well-presented manuscript also allowing the comprehension of the topic for a non-specialist covers in an exhaustive manner several aspects such as the organic chemistry of amidoximes, their coordination chemistry, the structural diversity including crystallography. The potential for a technological application, notably the retention and extraction of uranyl salts dissolved in seawater is also addressed.
Note however, that another thematical related review article “Amidoxime-based materials for uranium recovery and removal” has been recently publish and must be cited and commented (J. Mater. Chem. A, 2020,8, 7588-7625).
Another point requiring some minor revision is the technical poor quality of some equations. These reaction schemes would also benefit from some coloring.
So, in conclusion, I think that this contribution fits well for the Special Issue: Coordination Chemistry: Current Developments and Future Perspectives.
Author Response
Reviewer 2
Although I'm rather expert for the coordination chemistry of transition metals then f-block elements, I have much appreciated the lecture of this quite comprehensive review article on the coordination chemistry of Uranyl- salts ligated by amidoxime ligands. This well-written and scholarly well-presented manuscript also allowing the comprehension of the topic for a non-specialist covers in an exhaustive manner several aspects such as the organic chemistry of amidoximes, their coordination chemistry, the structural diversity including crystallography. The potential for a technological application, notably the retention and extraction of uranyl salts dissolved in seawater is also addressed.
We thank the reviewer for her/his warm comments.
Note however, that another thematical related review article "Amidoxime-based materials for uranium recovery and removal" has been recently publish and must be cited and commented J. Mater. Chem. A, 2020,8, 7588-7625).
This point was also raised by Reviewer 1. The suggested review has been mentioned and commented (ref. [9] in the revised ms). Due to this addition (but also because of other changes-please see our responses to Reviewer 1), the numbering scheme of the references has been changed.
Another point requiring some minor revision is the technical poor quality of some equations. These reaction schemes would also benefit from some coloring.
This correct comment was also raised by Reviewer 1. As we explained in our response to Reviewer 1, when we uploaded the original ms, all equations were in the correct format and their technical quality was perfect. The observed discrepancies were derived from the journal’s system. We are not responsible for this and we apologize to the reviewer. In order to avoid further inconvenience with the ChemDraw equations, we have incorporated the same equations as images in the manuscript.
We thank Reviewer 2 for her/his time to study the ms and the valuable comments/suggestions which contribute to the quality of the work.
Round 2
Reviewer 1 Report
Just one suggestion for 5.1 section title:
The beginning of the story: the uranyl-acetamidoxime and uranyl-benzamidoxime chemistry
