Activation of dioxygen by an yttrium iodide adduct: First example of an yttrium superoxide displaying also a rare 1,1-bridging mode of the superoxide ligand

YI3(PriOH)4 (1), obtained from the reaction between yttrium chips and iodine in isopropanol, reacts with dioxygen to give a superoxide bridged dinuclear ionic species [Y2I2(μ2,μ0:η1-O2)2(PriOH)8][I]2 (2). The ligand exchange reaction of 1 with N,N-dimethylaminoethanol (dmaeH) afforded YI3(dmaeH)4 (3). Complex 2 is the first structurally characterised yttrium superoxide derivative. In addition, it displays a rare μ2,μ0:η1 bonding mode of image, unknown in transition metal chemistry. 2 is also the first example of a superoxide derived from a metal iodide. The DFT calculations on a model compound, where the PriOH molecules of 2 are replaced by water molecules, i.e. for [Y2I2(μ2,μ0:η1-O2)2(H2O)8][I]2 (2a), show that this molecule is stable in its high spin triplet state with the SOMO–LUMO gap being 3.7 eV.