The First End‐On Bonded Superoxo Complexes of Ga and In: The Oxygen‐Rich Compounds GaO 4 and InO 4

We report the first sighting and characterization of the oxygen‐rich molecules GaO 4 and InO 4 , being the products of a three‐step process taking place in an Ar matrix. This process includes (i) reaction of Ga or In atoms (M) with one dioxygen molecule to give the cyclic superoxo complex MO 2 , (ii) photoisomerization into linear OMO by the action of UV light, and (iii) reaction of linear OMO with an additional O 2 molcule. The molecules can be described as end‐on bonded superoxo complexes OMO(O 2 ). On the basis of the observed isotopic data the O–Ga–O angle can be estimated to be ca. 165°. In addition to the experimental studies, quantum chemical calculations were performed to achieve a more complete characterization of these interesting new and unusual molecules, representing the first ever found examples of end‐on bonded superoxo complexes of Ga and In. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)