Molecular and electronic structure of a trinuclear oxo-centred Iron(III) complex with trigonal bipyramidal metal sites

A μ3-oxotriiron(III) complex with isovalent ferric sites was synthesized in the reaction of iron(II) triflate and the new ligand, 1,4-di-(2′-N-methylbenzimidazolyl)aminophthalazine (H2L). The [Fe3OL3]+ cluster is formed in a one-pot, self-assembly reaction when the inert reaction mixture is exposed to dioxygen. The complex exhibits a triple-helical ligand arrangement and unprecedented homochiral trigonal bipyramidal iron-ligand framework. X-ray structural analysis shows typical isosceles distortion of the Fe3 triangle with Fe–Fe distances of 3.330 and 3.305 Å. Spectroscopic, magnetic and electrochemical properties of the [Fe3OL3]+ compound is discussed in the article.