Rhodium and iridium NNO-Scorpionate complexes: synthesis, structure, and reactivity with aluminum alkyls

Synthesis of rhodium and iridium NNO (NNO = bis(3,5-dimethyl-pyrazol-1-yeacetate) complexes is reported. Complexes have been fully characterized by H-1 and C-13{H-1} NMR spectroscopy, mass spectrometry and X-ray diffraction. Addition of K(NNO) to [M(cod)Cl](2) results in formation of a new, fluxional species, M(cod)(NNO), which crystallizes as a bimetallic M(I)-M(I)dimer bridged by two NNO ligands. In contrast, addition of the protic starting material NNO-H to [Ir(cod)(2)] [BArF24] (BArF24 = tetrakis(3,5-trifluoromethylphenyl)borate) resulted in the Ir(III) hydride species [Ir(cod)(NNO)(H)]BArF24. Finally, the reactivity of the newly synthesized complexes with alkyl aluminum reagents, AlR3 (R = Et, Bu-i) is explored.