Structural and spectroscopical characterization of μ-oxo bridged Iron(III) bromide complexes of Pyclen ligands

Binuclear iron oxo-bridged complexes have found much interest since the early 80's as synthetic models for relevant biological molecules, catalysts and magnetic probes. In this work, a series of iron(III)bromide-based oxo-bridged complexes of Pyclen ligands was prepared, with the aim of investigating the peculiar iron-oxygen bond features in different molecular environments. We observed the influence of the steric hindrance of the ligands employed in this study towards the formation of symmetrical and non-symmetrical mu-oxo complexes, and we confirmed this peculiar behaviour by single crystal X-ray diffraction and Raman spectroscopy. We report here structural and spectroscopical insight of three unprecedented oxo-iron complexes and their relative precursors, enlarging the existing database of these particular class of metal complexes.