Structure Controlling Factors of Oxido-Bridged Dinuclear Iron(III) Complexes
Open Access
- 8 February 2021
- Vol. 26 (4), 897
- https://doi.org/10.3390/molecules26040897
Abstract
Oxido bridges commonly form between iron(III) ions, but their bond angles and symmetry vary with the circumstances. A large number of oxido-bridged dinuclear iron(III) complexes have been structurally characterized. Some of them belong to the C2 point group, possessing bent Fe–O–Fe bonds, while some others belong to the Ci symmetry, possessing the linear Fe–O–Fe bonds. The question in this study is what determines the structures and symmetry of oxido-bridged dinuclear iron(III) complexes. In order to gain further insights, three oxido-bridged dinuclear iron(III) complexes were newly prepared with 2,2′-bipyridine (bpy) and 1,10-phenanthroline (phen) ligands: [Fe2OCl2(bpy)4][PF6]2 (1), [Fe2O(NO3)2(bpy)4][PF6]2·0.6MeCN·0.2(2-PrOH) (2), and [Fe2OCl2(phen)4][PF6]2·MeCN·0.5H2O (3). The crystal structures of 1, 2, and 3 were determined by the single-crystal X-ray diffraction method, and all of them were found to have the bent Fe–O–Fe bonds. Judging from the crystal structure, some intramolecular interligand hydrogen bonds were found to play an important role in fixing the structures. Additional density functional theory (DFT) calculations were conducted, also for a related oxido-bridged dinuclear iron(III) complex with a linear Fe–O–Fe bond. We conclude that the Fe–O–Fe bridge tends to bend like a water molecule, but is often stretched by interligand steric repulsion, and that the structures are mainly controlled by the intramolecular interligand interactions.Keywords
Funding Information
- Japan Society for the Promotion of Science (15K05445)
This publication has 28 references indexed in Scilit:
- Oxidative renal tubular injuries induced by aminocarboxylate-type iron (III) coordination compounds as candidate renal carcinogensBioMetals, 2006
- μ-Oxo-bis{chloro[N-(2-methoxyethyl)-N,N-bis(pyridin-2-ylmethyl)amine-κ4-N,N′,N′′,O]iron(III)} bis(trifluoromethanesulfonate) acetonitrile disolvateActa Crystallographica Section E Structure Reports Online, 2005
- How iron-containing proteins control dioxygen chemistry: a detailed atomic level description via accurate quantum chemical and mixed quantum mechanics/molecular mechanics calculationsCoordination Chemistry Reviews, 2003
- In situ study of the goethite-hematite phase transformation by real time synchrotron powder diffractionAmerican Mineralogist: Journal of Earth and Planetary Materials, 1999
- Synthesis, crystal structure and properties of [Fe2O(bipy)4C12](ClO4)2 · 0.25CH3CN · 0.25CH30H · 0.25H2O, a μ-Oxo diiron(III) complexPolyhedron, 1998
- Chemical Basis for High Activity in Oxygenation of Cyclohexane Catalyzed by Dinuclear Iron(III) Complexes with Ethereal Oxygen Containing Ligand and Hydrogen Peroxide SystemZeitschrift für Naturforschung B, 1997
- Chemical origin of high activity in oxygenation of cyclohexane by H2O2 catalysed by dinuclear iron(III) complexes with amide-containing ligandsJ. Chem. Soc., Dalton Trans., 1996
- Synthesis and Reactivity of (.mu.-Oxo)diiron(III) Complexes of Tris(2-pyridylmethyl)amine. X-ray Crystal Structures of [tpa(OH)FeOFe(H2O)tpa](ClO4)3 and [tpa(Cl)FeOFe(Cl)tpa](ClO4)2Inorganic Chemistry, 1994
- The crystallographic information file (CIF): a new standard archive file for crystallographyActa Crystallographica Section A Foundations of Crystallography, 1991
- Precipitation in hydrolysed iron(III) solutionsJournal of Inorganic and Nuclear Chemistry, 1974