Magnetic and Electrochemical Properties of Lantern-Type Dinuclear Ru(II,III) Complexes with Axial Chloride Ions or Water Molecules
, Haruki Yairi 1, Natsumi Yano 1, Minoru Mitsumi 2, Hiroshi Sakiyama 3, Masaharu Kitashima 4, Kazuhito Inoue 4, Ryoji Mitsuhashi 5, Masahiro Mikuriya 5, Haruo Akashi 6 and Yusuke Kataoka 1,*
Round 1
Reviewer 1 Report
1. It would be better to plot three diruthenium units for a zig-zag chain structure in Scheme 1.
2. For a triclinic space group of complex 2, there is only one inversion center in a unit cell.
Lines 107-108, the assignment of two inversion centers is not common.
3. The atom symbolling of Cl3-Ru4-Ru4’’’-Cl4’’’ is not correct in Figure 2S.
4. Lines 179-180, 187 and 312, the formula of [Ru2{O2C(CH3)3}4(HO)2]BF4 and [Ru2{O2C(CH3)3}4(HO)2]BF4.CH2Cl2 are missed one C atom.
5. The magnetic susceptibility data of complexes 1-3 are plotted in one figure.
6. Line 314, the UV assignment, d*/p*(Ru2) →d* (Ru-O), is not reasonable since d* (Ru-O) bonding is not common.
Is it possible to address any information from the results of DFT calculation?
7. Is the results of DFT confirmed to the magnetic data S=3/2?
8. Lines 427 and 439: Ru2, 44.49 and Ru2, 28.54 both C atoms are missed.
Comments for author File: 
Comments.pdf
Author Response
Thank you very much for useful comments to improve the manuscript.
1. It would be better to plot three diruthenium units for a zig-zag chain structure in Scheme 1.(response) According to the suggestion, the figure was remade for Scheme 1.
2. For a triclinic space group of complex 2, there is only one inversion center in a unit cell. Lines 107-108, the assignment of two inversion centers is not common.
(response) The inversion center is not necessarily one, even in a tricilinic space group. The symetry operations are described in the caption of Figure 1.
3. The atom symbolling of Cl3-Ru4-Ru4’’’-Cl4’’’ is not correct in Figure 2S.
(response) The atom symbolling is not incorrect because of the reason for the previus comment.
4. Lines 179-180, 187 and 312, the formula of [Ru2{O2C(CH3)3}4(HO)2]BF4 and [Ru2{O2C(CH3)3}4(HO)2]BF4.CH2Cl2 are missed one C atom.
(response) Thank you very much for the comment. The missing C atoms are all added correctly.
5. The magnetic susceptibility data of complexes 1-3 are plotted in one figure.
(response) That is good idea. But, in the present case, all the data values are close and superposed if they are plotted in one figure. Hence, they are plotted in different figures.
6. Line 314, the UV assignment, d*/p*(Ru2) →d* (Ru-O), is not reasonable since d* (Ru-O) bonding is not common. Is it possible to address any information from the results of DFT calculation?
(response) We carefully checked the assignment. However, the assignment is correct. In the lines 319-321 of the revised manuscript, reference of diffuse reflectance spectra was added (ref. 18) and more detailed explanation for the assignment is described here. For the assignment, different calculation (TD-DFT) should be made. This is a hard and overwhelming task and is beyond the scope we are aiming at in this paper.
Reviewer 2 Report
This paper address the magnetic and electrochemical properties of a Series Ru(II,III) complexes. This topic is potentially interesting to the audience of magnetochemsitry. However, there are some typos which are needed to be changed.
i)Starting from page 4, some of the compound are labeled with [Ru2[O2C(CH3)3]4(H2O)2]... How can any carbon after bond to two oxygen (probably with one double bond, even) then bond to Three Methyl group? What is that supposed to mean?
ii)Starting from page 7, the CV part of this paper, the author sometimes label the 1.3~1.4 V peak as Ru25+->Ru24+, sometime give it Ru26+->Ru25+. Which one should be the right answer?
iii) It is a big question raised by this paper that if Prof. Cotton's proposal is correct especially in solution. Actually, this question can be answered by conductivity experiment. The authors should finish this measurement then can be considered to be published on magnetochemistry.
Author Response
(Comments from Reviewer 2) This paper address the magnetic and electrochemical properties of a Series Ru(II,III) complexes. This topic is potentially interesting to the audience of magnetochemsitry. However, there are some typos which are needed to be changed. i)Starting from page 4, some of the compound are labeled with [Ru2[O2C(CH3)3]4(H2O)2]... How can any carbon after bond to two oxygen (probably with one double bond, even) then bond to Three Methyl group? What is that supposed to mean? ii)Starting from page 7, the CV part of this paper, the author sometimes label the 1.3~1.4 V peak as Ru25+->Ru24+, sometime give it Ru26+->Ru25+. Which one should be the right answer? iii) It is a big question raised by this paper that if Prof. Cotton's proposal is correct especially in solution. Actually, this question can be answered by conductivity experiment. The authors should finish this measurement then can be considered to be published on magnetochemistry.
Thank you very much. This comment is vey important to improve the manuscript. (response) 1) [Ru2[O2C(CH3)3]4(H2O)2] was corrected to [Ru2[O2CC(CH3)3]4(H2O)2], because “C” was missed. There are same mistakes in the text. They were all corrected. 2) At the line 380 of the revised manuscript, Ru25+ → Ru24+ was corrected to Ru26+ → Ru25+. 3) It was found to be very difficult to measure the conductivity in CH2Cl2. Hence, we removed the sentences “It is strange why all the complexes of 1–3 show Ru25+ → Ru24+ process similarly at -0.2 – -0.4 V (vs. SCE)”, “If the equilibrium proposed by Cotton et al. exists in the solution, the redox behaviors concerning the Ru25+ → Ru24+ process should be different” and “At least, we could say that we did not confirm the equilibrium shown by [Ru2(O2CC3H7)4]+ + n(Cl-) ↔ [Ru2(O2CC3H7)4Cln](n-1)-”. In the revised manuscript, we only focus on describing the obtained results at the lines form 360 to 387.
Reviewer 3 Report
This paper is clear and easy to read.
I’m not so much familiar with Ru25+ complexes and some clarification of text could be appreciable. The ground state of the complexes is S=3/2, in this case, which is the oxidation state of each ion?
Between dimer you shown that there is no anti-ferromagnetic interaction. Is there any magnetic interaction inside the dimer?
The g and D parameter given are for the complexes or for the ion?
Other section are clear and understandable
Also I have some minor comment:
the paddle type and lantern type complex are same?
Line 91: “formula” instead of “formulae”
Line 92: O-C-C is correct or it should be COO
Line 358: TBAP is not defined. If it is TBA PF6, the correct abbreviation should be TBAHP
Line 449: “were” instead of “ware”
In all text: the correct minus sign should be “–“ instead of “-”
Author Response
Thank you very much for the useful comment to improve our manuscript.
(reviewer's comment) The ground state of the complexes is S=3/2, in this case, which is the oxidation state of each ion?
(response) It is difficult to distinguish which metal has oxidation state of 2 or 3. Hence, we described as Ru25+, which has S= 3/2 spin state.
(reviewer's comment) Between dimer you shown that there is no anti-ferromagnetic interaction. Is there any magnetic interaction inside the dimer?
(response) Yes, there is a very strong interaction within the dinclear unit to form new molecular orbitals between the metals.
(reviewer's comment) The g and D parameter given are for the complexes or for the ion?
(response) The g and D parameter are given for the dinuclear complexes.
(reviewer's comment) The paddle type and lantern type complex are same?
(response) Actually, they are the same.
(reviewer's comment) .Line 91: “formula” instead of “formulae”
(response) Thank you for the comment. The mistake was corrected in the revised manuscript at the line 87 of the revised manuscript.
(reviewer's comment) Line 92: O-C-C is correct or it should be COO
(response) Thank you very much for the comment. The mistake was corrected in the revised manuscript (at line 88 of the revised manuscript).
(reviewer's comment) Line 358: TBAP is not defined. If it is TBA PF6, the correct abbreviation should be TBAHP
(response) According to the other reviewer, e.g., TBAP was defined as nBu4N(ClO4).
(reviewer's comment) Line 449: “were” instead of “ware”
(response) That is an awful mistake, which was corrected in the revised manuscript (at line 452 of the revised manuscript).
(reviewer's comment) In all text: the correct minus sign should be “–“ instead of “-”
(response) According to the suggestion, the minus signs ere all revised to the long hyphen “–“.
Reviewer 4 Report
The authors present synthesis and characterization of some paramagnetic latern-type diruthenium compounds. Before it can be accepted, the following comments should be addressed.
There is a too much repetition throughout the manuscript. The countercation, tetrabutylammonium should be correctly inscribed [N(nBu)4], with the definition given in the first usage negating the need to repeat the name every time there is a new anion. Similarly for tetrafluoroborate - once to define BF4-, and then just the formula.
Reduction potentials are referenced to the saturated calomel electrode, and this must be stated in the experimental section. There is no need to "(vs SCE)" every time a reduction potential is mentioned - a table would be helpful to summarize the electrochemical data.
The method for calculating reduction potentials is not well explained. There should be references to the method, and total and free energies given for the solvated and gas phase calculations. Optimized coordinates should be included in the Supplementary Information. It is also not clear how the calculated reduction potential was calibrated to the SCE reference electrode, whether this was calculated or a known value was sourced.
Cl- ligands are correctly named "chloro" and not "chlorido". Similarly halide ligands rather than halgenido. References to citations should be removed from the abstract, i.e. Cotton et al. The use of et al. is incorrect here is Cotton is not the first author, and so it is correctly written "Cotton and co-workers" or "Bennett et al." There are other instances were et al. is used though not with the name of the first author.
The ESR simulation is not a computation; rather, this sentence should be moved to section 3.1. The simulations are also incorrect. The spin-Hamiltonian given in the experimental section includes the hyperfine term, yet there are no hyperfine features in these spectra. But the zero-field splitting term, S·D·S, is not in the spin-Hamilitonian, yet these are S = 3/2 species with large D-values. Using the correct spin-Hamiltonian would allow the authors to determine the rhombicity, E/D, of the zero-field interaction. The EPR spectra have been simulated using effective g-values, which are different to intrinsic g-values that the authors list when highlighting the work of Telser et al., and Cukiernik et al., lines 282-285. The experimental conditions for the EPR measurements are missing and need to be added.
Ref 14 needs to be combined with Ref 7, as this a just a correction. It would be worthwhile removing the zJ' term entirely from the fit of the susceptibility data as this parameter cannot be determined.
Author Response
Thank you very much for very useful comments to improve our manuscript.
(reviewer's comment) There is a too much repetition throughout the manuscript. The countercation, tetrabutylammonium should be correctly inscribed [N(nBu)4], with the definition given in the first usage negating the need to repeat the name every time there is a new anion. Similarly for tetrafluoroborate - once to define BF4-, and then just the formula.
(response) According to the comment, “nBu4N “ and “BF4-“ were used instead of “tetrabutylammonium” and “tetrafluoroborate” after their definition in the revised manuscript.
(reviewer's comment) Reduction potentials are referenced to the saturated calomel electrode, and this must be stated in the experimental section. There is no need to "(vs SCE)" every time a reduction potential is mentioned - a table would be helpful to summarize the electrochemical data.
(response) According to the comment, “vs. SCE” was all removed. In the experimental section (at 420-421 lines), the sentence “All the potential values are described versus SCE “ was added. Although it is good suggestion to summarize the results in a table, we do not give a detailed discussion on the redox values and Figure 11 describing CVs of the complexes is considered to be enough to be understood for their redox properties.
(reviewer's comment) The method for calculating reduction potentials is not well explained. There should be references to the method, and total and free energies given for the solvated and gas phase calculations. Optimized coordinates should be included in the Supplementary Information. It is also not clear how the calculated reduction potential was calibrated to the SCE reference electrode, whether this was calculated or a known value was sourced.
(response) The DFT calculated values (in eV) were inverted to the SCE potential values according to the literature. The details on the treatment to obtain the energy values are given also in the literature. Refs. 23 and 24 are added in the revised manuscript as the literatures. Optimized coordinates are effective for the special case such that abnormal bond lengths are discussed. In order to calculate the potential values, in the present study, 9 geometrical calculations (for Ru26+, Ru25+ and Ru24+ for [Ru2(O2CC3H7)4Cl2]-, [Ru2(O2CC3H7)4Cl], and [Ru2(O2CC3H7)4(H2O)2]+) should be made. The enormous numeric data on the optimized coordinates may not be needed for usual readers.
(reviewer's comment) Cl- ligands are correctly named "chloro" and not "chlorido". Similarly halide ligands rather than halgenido. References to citations should be removed from the abstract, i.e. Cotton et al. The use of et al. is incorrect here is Cotton is not the first author, and so it is correctly written "Cotton and co-workers" or "Bennett et al." There are other instances were et al. is used though not with the name of the first author.
(response) Following revisions were made: 1) According to IUPAC Recommendations 2005, “chlorido” is recommended. We use “chloride” (at 276 line of the revised manuscript) and “halide” (at 279 line) are used to avoid the use of “chlorido” and “halogenido”. 2) In the abstract, reference citation was removed. 3) At 47 line of the revised manuscript, “Cotton et a.” was changed to "Cotton and co-workers".
(reviewer's comment) The ESR simulation is not a computation; rather, this sentence should be moved to section 3.1. The simulations are also incorrect. The spin-Hamiltonian given in the experimental section includes the hyperfine term, yet there are no hyperfine features in these spectra. But the zero-field splitting term, S·D·S, is not in the spin-Hamilitonian, yet these are S = 3/2 species with large D-values. Using the correct spin-Hamiltonian would allow the authors to determine the rhombicity, E/D, of the zero-field interaction. The EPR spectra have been simulated using effective g-values, which are different to intrinsic g-values that the authors list when highlighting the work of Telser et al., and Cukiernik et al., lines 282-285. The experimental conditions for the EPR measurements are missing and need to be added.
(response) Thank you very much for the good comments, which helps us improve the manuscript. Following revisions were made: 1) According to the comment, the explanation of EPR simulation was moved to 3.1 2) As has been pointed out, the spin-Hamiltonian should not include the hyperfine term, which was deleted. Although the spin-Hamiltonian does not contain the zero-field splitting term, the simulations could be well done, because the measured temperature was low (5K) enough to be analyzed. 3) At the 308 -311 lines of the revised manuscript. We gave the explanation on the effective g values. Our previous report was newly added as ref. 17, in addition to ref. 7. 4) The experimental condition (EPR spectra were measured at 5 K in solid) was described in the experimental section at 415 line of the revised manuscript.
(reviewer's comment) Ref 14 needs to be combined with Ref 7, as this a just a correction. It would be worthwhile removing the zJ' term entirely from the fit of the susceptibility data as this parameter cannot be determined.
(response) Thank you very much again for the good comments. According to the suggestion, following revisions were made: 1) Ref.14 was inserted into the Ref. 7. 2) zJ term was removed from the analyzing equation (1) – (5), hence they are renamed as (1) – (4) in the revised manuscript. The definition of zJ was written in the 270 line, because zJ is discussed on the relationship to the structural parameter Ru-X/Ru-X-Ru in the following sentence (at 280 line)
Round 2
Reviewer 2 Report
The authors have satisfied all the comments.
Author Response
Comments from Reviewer 2
The authors have satisfied all the comments.
(response)
We think that our responses were accepted by the reviewer. The previous comments were really helpful to improve the manuscript. We appreciate the comments.
Reviewer 4 Report
Nevertheless the authors should provide a list of atomic coordinates for all optimized structures (there are only 56 atoms) and the thermodynamic energies upon which they have estimated the reduction potentials. A schematic depiction of the Born-Haber cycle can also be added to the SI to aid the reader.
There is also a typographical error on line 310 for the intrinsic g-value.
Measured is misspelled in Figure S4.
Author Response
Comments from Reviewer 4
1) Nevertheless the authors should provide a list of atomic coordinates for all optimized structures (there are only 56 atoms) and the thermodynamic energies upon which they have estimated the reduction potentials. A schematic depiction of the Born-Haber cycle can also be added to the SI to aid the reader.
(response)
According to the comments, all the atomic coordinates of optimized geometries needed for the estimations for the redox values are given at Tables S3 – S11. Because the scheme of Born Harbor cycle and details on the Gibbs free energy changes are described in the literature reported by Noodleman and co-workers (Inorg. Chem., 1996, 35, 4694-4702 (ref. 23)), the procedure to estimate the redox potentials (Ecalc1/2) for Ru25+ Ru24+ and Ru26+ Ru25+ processes was described simply at 476-480 lines of the revised manuscript. If readers want to estimate the values by themselves using DFT calculation, they can check their results referring to the atomic coordinates given at Tables S3 – S11. Thank you very much for the useful comment.
2) There is also a typographical error on line 310 for the intrinsic g-value.
(response)
According to the comment, the g value was corrected to g = 2.168.
Thank you very much!
3) Measured is misspelled in Figure S4.
(response)
Correction to “measured” was made in Figure S4.
Thank you very much! (because we did not find the mistake).
