NO • Disproportionation by a {RhNO} 9 Pincer-Type Complex

Abstract

The reactivity of the {RhNO}9 complex [Rh(PCPtBu)(NO)] (1) with NO was studied. A disproportionation reaction takes place in which N2O is released quantitatively, while the complex Rh(PCPtBu)(NO)(NO2) (2), with coordinated nitrite, is formed. The new complex 2 was fully characterized by multinuclear NMR techniques, IR and X-ray diffraction. The X-ray structure reveals a square pyramidal geometry with an N-bound nitro ligand trans to the Cipso of the PCP ligand and a bent nitrosyl ligand in the apical position. IR measurement of released N2O confirms that one equivalent forms for each molecule of 1. Infrared spectroscopic experiments with 1-15NO and 14NO suggest that the reaction occurs through the intermediacy of a dinitrosyl complex. In addition, DFT calculations were performed to provide more evidence on the structure of the intermediates and to support the observed reactivity.