Carbonylmolybdenum complexes with di(imino)pyridine and related ligands: Reduction of a di(imino)pyridine to an aminoiminopyridine system under mild conditions

The reactions of [Mo(CO)6] towards a 2,6-di(imino)pyridine L1 and related ligands were studied. The reaction with L1 afforded two new complexes, [Mo(CO)4L1] (1) and [Mo(CO)4L2] (2), where L2 is the 2-amino-6-iminopyridine ligand arising from the hydrogenation of one imine function of L1; similar reaction with a 2-acetyl-6-iminopyridine ligand L3 afforded [Mo(CO)4L3] (3). Compounds 1, 2 and 3 have been fully characterised by IR, 1H NMR and X-ray crystallography; they present a metal ion in a pseudo-octahedral environment, the three organic ligands acting with bidentate N2 coordination modes. One of the imine functions in 1, the amine function in 2, and the ketone function in 3 are uncoordinated.