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 O2−, 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.

Graphical abstractYI3(PriOH)4 (1), obtained from the reaction between yttrium chips and iodine in isopropanol, reacted with dioxygen to give a dinuclear ionic species [Y2I2(μ2,μ0:η1-O2)2(PriOH)8][I]2 (2). It is the first structurally characterized yttrium superoxide derivative as well as the first superoxide derived from an iodide. In addition, it displays a rare μ2,μ0:η1 bonding mode of O2−. DFT calculations indicate that this molecule is stable in its high spin triplet state.Figure optionsDownload full-size imageDownload as PowerPoint slide