Structure and Reactivity of Dinitrogen Rhodium Complexes Containing N‐Heterocyclic Carbene Ligands

Abstract The rhodium bis‐carbene complex [Rh(IPr) 2 (N 2 )Cl], where IPr = 1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene, has been synthesized and characterized. The complex is a rare example of a four‐coordinate rhodium complex featuring nitrogen bound end‐on. While quite stable as a solid under inert atmosphere, in solution the N 2 ligand has been found to be quite labile. This lability has been exploited in the synthesis of complexes with the formula [Rh(IPr) 2 (XY)Cl], where XY = O 2 , H 2 and CO. Interestingly, the dihydride coordination leads to oxidation of the metal centre to Rh III , even though previous studies from our lab have shown that Rh remains in the +1 oxidation state upon coordination of dioxygen. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)