Reduction of organic azides by indyl-anions. Isolation and reactivity studies of indium-nitrogen multiple bonds

The synthesis of a new potassium-indyl complex, K[In(NON^Ar)] (NON^Ar = [O(SiMe₂NAr)₂]^2-, Ar = 2,6-ⁱPr₂C₆H₃) and its reactivity with organic azides RN₃ is reported. When R = 2,6-bis(diphenylmethyl)-4- Bu-phenyl, a dianionic alkyl-amide ligand is formed via C-H activation across a transient In-N_imide bond. Reducing the size of the R-group to 2,4,6-trimethylphenyl (mesityl, Mes) enables oxidation of the indium and elimination of dinitrogen to afford the imide species, K[In(NON^Ar)(NMes)]. The anion contains a short In-N_imide bond, shown computationally to contain appreciable multiple bond character. Reaction of isolated imides with an additional equivalent of azide (R = Mes, SiMe₃) generates tetrazenido-indium compounds K[In(NON^Ar){κ-N,N'-N₄(Mes)(R)-1,4}], shown by X-ray crystallography to contain planar InN₄ heterocycles in the anion.