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(NONAr )] (NONAr = [O(SiMe2 NAr)2 ]2- , Ar = 2,6-i Pr2 C6 H3 ) and its reactivity with organic azides RN3 is reported. When R = 2,6-bis(diphenylmethyl)-4- t Bu-phenyl, a dianionic alkyl-amide ligand is formed via C-H activation across a transient In-Nimide 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(NONAr )(NMes)]. The anion contains a short In-Nimide 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(NONAr ){κ- N , N '-N4 (Mes)(R)-1,4}], shown by X-ray crystallography to contain planar InN4 heterocycles in the anion.