Abstract
In the present study, iron complexes modified by differently substituted monodentate pyridine ligands containing a [Fe-O-Fe] unit have been synthesized, isolated and characterized. Noteworthy, the complexes are easily accessible by the reaction of pyridines with iron(II) chloride in the presence of molecular oxygen, which is the source for the oxido bridge as proven by labelling experiments. ...
Abstract
In the present study, iron complexes modified by differently substituted monodentate pyridine ligands containing a [Fe-O-Fe] unit have been synthesized, isolated and characterized. Noteworthy, the complexes are easily accessible by the reaction of pyridines with iron(II) chloride in the presence of molecular oxygen, which is the source for the oxido bridge as proven by labelling experiments. Interestingly, in dependency of the electronic and steric properties of the applied ligand different geometries have been observed by X-ray diffraction analysis. On one hand with pyridine or 4-dimethylaminopyridine as ligand (L) a L4ClFe-O-FeCl3 motif was accessible, while with 4-tert-butylpyridine a L2Cl2Fe-O-FeCl2L2 motif was realized. With the aid of Mossbauer spectroscopy an oxidation state +III was assigned for all iron centres. Moreover, the complexes were easily converted by addition of silver benzoate to trinudear complexes with a [Fe3O] core. (C) 2016 Elsevier B.V. All rights reserved.