Spin Crossover in Three Mononuclear Iron (III) Schiff Base Complexes
Round 1
Reviewer 1 Report
My comments are in the file enclosed.
Comments for author File: Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
The authors reported the crystal structures, magnetic susceptibility, and theoretical calculations of new spin crossover mononuclear Fe(III) complexes. The experimental results were sound, but insufficient. Moreover, the conclusion was not supported by the experimental and theoretical results. Therefore, I would like to reconsider publication of this manuscript after the authors address all the following points.
Why did the authors determine the crystal structures at 190 K for 2a and at 293 K for 2b? From the magnetic susceptibility, the complexes 2a and 2b showed spin crossover at those temperatures. The bond lengths and angles for the coordination bonds should be compared at the same temperature. Moreover, the thermal variation of bond lengths and angles is the evidence of spin crossover. I recommend the authors should determine the crystal structures for all complexes at 100 and 293 K.
Although the calculations are performed for a single molecule of a spin crossover complex at the gas phase, the authors compared the calculation results with the thermodynamic parameters from the solid-state magnetic susceptibility. The effect of crystal packing and intermolecular interactions cannot be ignored for a spin crossover complex in the solid-state. If the authors would like to compare the energies between the high-spin and low-spin states by calculation, they should measure the temperature dependence of magnetic susceptibility in the solution.
Minor points
Line 53: Scheme 1 is missing. The structural formulas of the ligands and complexes should be included in the text.
Line 55: The composition of 2a was strange. The elemental analysis indicated [Fe(3EtO-LA)(L1b)](BPh4)·2CH3OH, whereas the crystal structure determination described [Fe(3EtO-LA)(L1b)](BPh4)·CH3OH.
Lines 99-104: Percentage is not a unit, thus it must be followed by a value. The space between the value and percent sign should be deleted.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The description of this manuscript is based on the supposition the present complexes showed spin crossover. However, this is not the case in the present form of this manuscript. The authors argued that spin-crossover was evident from the temperature-dependent magnetic susceptibility. However, the possibility of the antiferromagnetic coupling between the Fe(III) cations is not excluded only by these magnetic data. I can suggest that the authors can list the table that contains the coordination bond lengths and distortion angles both of the present Fe(III) complexes and the previously reported Fe(III) complexes from the same ligand whose spin-state was characterized by another experimental technique.
By the structural formulas added by the authors, I calculated the formulas C55B1Fe1H57N5O4 for 1a, C60B1Fe1H62N4O6 for 2a, and C55B1Fe1H50N4O3 for 2b. The authors should check the composition of 1a.
Author Response
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Author Response File: Author Response.pdf
Round 3
Reviewer 2 Report
I accept the authors' revision.