ortho-Metallation reactions. Part II. Some ruthenium complexes containing the phenylazophenyl group

Abstract

The reactions of [(azb)Ru(CO)₂Cl]₂(azb = 2-phenylazophenyl) with several different ligands have been studied. Monodentate ligands, L, cleave the halogen bridge to give monomeric complexes (azb)LRu(CO)₂Cl. The bidentate ligand, 2,2′-bipyridyl (bipy), gives the ionic complex [(azb)Ru(CO)₂(bipy)][(azb)Ru(CO)₂Cl₂]: this contains a rare example of a cationic Ru–C σ-bond. Cyclopentadienide and tris(pyrazolyl)borate anions react initially to give complexes containing phenylazophenyl-2C groups; strong heating or irradiation convert them into chelating phenylazophenyl-2C,N′ complexes with loss of carbon monoxide. Other anionic chelates, e.g. acetylacetonate or o-aminobenzenethiolate, give monomeric (azb)Ru(CO)₂(chelate) complexes; benzenethiolate gives dimeric [(azb)Ru(CO)₂(SPh)]₂, a compound containing SPh bridging groups.