Efficient synthesis of carborane azo derivatives and their reactivity.

An iridium(iii)-catalyzed C-N-bond-forming direct synthesis of carborane azo derivatives was developed. The reaction of o-carborane monocarboxylate with aryldiazonium salt in the presence of a catalytic amount of [Cp*IrCl2]2 and NaOAc in CH3CN at 80 °C gave the corresponding carborane azo derivative in good yield. A series of cyclometalated iridium/rhodium complexes that contain Cp*M-B (M = Ir, Rh) bonds, and are stabilised by the intramolecular coordination of nitrogen donors, were successfully isolated and structurally characterised.