| Abstrakt: |
In the present work, we have studied the effect of the axial ligands, solvation, and oxidation and reduction on the structure and the nature of the Fe–Fe bonding of [Fe3L3] complex. The NCS−, CN−, and NO3− ions have been placed at the axial position of the [Fe3L3], giving [Fe3L3X2], where X represents NCS−, CN−, and NO3− ions. Our DFT results show that the structure of the [Fe3L3] molecule remains symmetrical regardless of the nature of the capped ligand. The ΔFe–Fe value is 0.01 Å, which falls within the range of symmetrical values (ΔM–M within 0.05 Å) of all the three complexes: [Fe3L3CN2], [Fe3L3(NCS)2], and [Fe3L3(NO3)2]. Next, we examined the solvation effect using benzene and toluene. Our results demonstrate no effect of solvation on the structure of [Fe3L3CN2] and [Fe3L3(NCS)2], as the ΔFe–Fe values remain consistent with the gas-phase structure and also X-ray value. Finally, in terms of the redox effect, our calculations indicate that the first oxidation process removes an electron from the σ* orbital, resulting in [Fe3L3]1+. This oxidation leads to unsymmetrical metal–metal bonds, with Fe1–Fe3 and Fe1–Fe2 measuring 2.35 Å and 2.52 Å, respectively. The second oxidation process removes another electron, this time from the δ* (HOMO-1) orbital, yielding [Fe3L3]2+. This electron removal also results in an unsymmetrical structure, with Fe1–Fe3 of 2.35 Å and Fe1-Fe2 of 2.53 Å, similar to that of the [Fe3L3]1+. This similarity is due to the removal of an electron from the weakly overlapped anti-bonding δ* orbital. The reduction process has a less pronounced effect on the structure of [Fe3L3] compared to that of the two-oxidation process. The Fe–Fe bond lengths of [Fe3L3]1− are the same as those of the natural molecule, with Fe1–Fe3 of 2.39 Å and Fe1–Fe2 of 2.42 Å. [ABSTRACT FROM AUTHOR] |
