Solution Equilibria Formation of Manganese(II) Complexes with Ethylenediamine, 1,3-Propanediamine and 1,4-ButanediaMine in Methanol
Round 1
Reviewer 1 Report
The authors in article present the spectrophotometric determination of manganese(II) complexes with some diamines (1,2-ethanediamine, 1,3-propandiamine, and 1,4-butandiamine) in methanol. The formation constants of six different complexes were determined, but neither of them was isolated and characterised. The authors have done nice work about spectroscopic speciation, but the aims of Molbank journal is publish the short works about synthesis of new compound and their characterisation with suitable methods (X-ray diffraction or multinuclear NMR).
For this reason, I think that the article in actual form is not acceptable for publication in Molbank journal.
Author Response
Response to Reviewer 1 Comments
Point 1: The authors in article present the spectrophotometric determination of manganese(II) complexes with some diamines (1,2-ethanediamine, 1,3-propandiamine, and 1,4-butandiamine) in methanol. The formation constants of six different complexes were determined, but neither of them was isolated and characterised. The authors have done nice work about spectroscopic speciation, but the aims of Molbank journal is publish the short works about synthesis of new compound and their characterisation with suitable methods (X-ray diffraction or multinuclear NMR).
For this reason, I think that the article in actual form is not acceptable for publication in Molbank journal.
Response 1: Is important to mention that the determination of the equilibrium constants for metal complexes and its speciation, is a method to actually characterize the complexes in solution. If a complex is characterized for example using X-ray diffraction, the change to use a method with solid samples to a method that use liquid samples might change the stoichiometry of the complex. This can also occurs if a complex is isolated and redisolving. The stoichiometry determination of the complexes in solution is a previous step to test the catalytic activity of a complex.
Reviewer 2 Report
In this study, the authors reported the equilibrium study on the formation of manganese(II) complexes with ethylenediamine (en), 1,3-propanediamine (pn) and 1,4-butanediamine (bn) in methanol. Although manganese(II) complexes mimicking the oxygen-evolving complex (OEC) in photosynthesis have been synthesized by using simple ligands in recent years, most of the ligands are nitrogen-donor aromatic ligands, and the studies on aliphatic diamine are still limited. In this paper, the authors showed the formation constants for the manganese(II) systems with en, pn, and bn in pure methanol using a spectrophotometric method for the first time. Although the results of crystallographic studies should be awaited to understand the detailed geometry of these manganese(II) complexes, the present results will contribute to the spectral studies on OEC, and therefore, this referee recommends that this paper is published in Molbank after the following revisions.
1) Line 145,
The title of the subsection is missing.
2) Line 146,
“Autho” should be deleted.
3) Line 211,
Is the subsection number 2.3?
4) Page 10,
The authors should comment in the revised text on the reason for difference between Figures 7a-7c. For example, why is the formation ratio of [Mn(pn)]2+ larger than that of [Mn(en)]2+ or [Mn(bn)]2+ for the solution with equimolar concentration of manganese(II) and the aliphatic diamine (en, pn, or bn)?
5) Figure 7,
The resolution and size of the image should be improved. In addition, the legends in Figure 7b should be checked. Shouldn't the legends of [Mn(pn)2]2+ and [Mn(pn)]2+ be replaced?
Author Response
Response to Reviewer 2 Comments
Point 1: Line 145,
The title of the subsection is missing.
Response 1: the line 176, 2.2 subsection was deleted
Point 2: Line 146,
“Autho” should be deleted.
Response 2: “Autho” was deleted
Point 3: Line 211,
Is the subsection number 2.3?
Response 3: there is no subsection 2.3
Point 4: Page 10,
The authors should comment in the revised text on the reason for difference between Figures 7a-7c. For example, why is the formation ratio of [Mn(pn)]2+ larger than that of [Mn(en)]2+ or [Mn(bn)]2+ for the solution with equimolar concentration of manganese(II) and the aliphatic diamine (en, pn, or bn)?
Response 4:At the end of section 2.2 was added a small paragraph with a brief explanation.
Point 5: Figure 7,
The resolution and size of the image should be improved. In addition, the legends in Figure 7b should be checked. Shouldn't the legends of [Mn(pn)2]2+ and [Mn(pn)]2+ be replaced?
Response 5: The resolution of Figure 7 was improved and the legends [Mn(pn)2]2+ and [Mn(pn)]2+ were changed.
Round 2
Reviewer 1 Report
I have no any comments.
