Coordination and Reactions of Diazenes in Trimethylphosphinecobalt(I). Complexes - Syntheses and Structures of Complexes Containing μ2-(N,N′)-Benzo[c]cinnoline and η2-Azobenzene Ligands

Mononuclear compounds CpCo(η2-azobenzene)(PMe3) (1) or ortho-metallated (2) are obtained from azobenzene and CpCo(PMe3)2 or CoMe(PMe3)4, respectively. With 4-acetoxo-azobenzene the ortho-metallation reaction gives isomers , (3A) and (3B) in a 1:1 ratio. Carbonylation of 2 gives (4). Benzo[c]cinnoline affords CoCH3(η2-C12H8N2)(PMe3)3 (5) and μ2-(N ,N′)-C12H8N2(CoCp)[CoCp(PMe3)] (6). The coordination mode of the diazene ligands in 1 and 6 has been shown by X-ray crystal structure determinations. Dynamic N M R spectroscopy indicates intramolecular hopping of trimethylphosphine across the CoCo bond in 6.