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

Abstract

Mononuclear compounds CpCo(η2-azobenzene)(PMe3) (1) or ortho-metallated Co-2-C6H4–N = N(C6H5)(PMe3)3 (2) are obtained from azobenzene and CpCo(PMe3)2 or CoMe(PMe3)4, respectively. With 4-acetoxo-azobenzene the ortho-metallation reaction gives isomers Co-2-C6H3(4-OAc)–N = N(C6H5)(PMe3)3 (3A) and Co-2-C6H4–N = N(4-OAc–C6H4)(PMe3)3 (3B) in a 1:1 ratio. Carbonylation of 2 gives Co-2-C6H4–N = N(C6H5)(PMe3)2CO (4). Benzo[c]cinnoline affords CoCH3(η2-Cl2H8N2)(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 NMR spectroscopy indicates intramolecular hopping of trimethylphosphine across the CoCo bond in 6. © 1993, Walter de Gruyter. All rights reserved.