The unexpected synthesis of rhodium(I) complexes with the 1-(2′-pyridyl)-3-oxo-1-propenoxide anionic ligand

The enaminone compound 1-(2′-pyridyl)-3-dimethylamine-1-propenone (1) reacts with [{Rh(μ-OY)(COD)}2] (OY=OMe, OH) dimers in the presence of water to form a mononuclear square-planar rhodium(I) complex 2, which incorporates the unexpected 1-(2′-pyridyl)-3-oxo-1-propenoxide ligand (N, O). The mediation of the metal in this ligand transformation is demonstrated. The crystal structure of [Rh(N,O)(COD)] (2) reveals the coordination of the new propenoxide ligand as a N,O-bidentate with the presence of an additional non-coordinated aldehyde group. Complex 2 reacts with CO by displacement of the COD molecule, but maintaining the N,O-coordination of the chelate propenoxide ligand.