Synthesis and characterization of new complexes of the type [Ru(CO)(2)Cl-2 (2-phenyl-1,8-naphthyridine-kN) (2-phenyl-1,8-naphthyridine-kN ')]. Preliminary applications in homogeneous catalysis

Abstract

Novel ruthenium (II) complexes were prepared containing 2-phenyl-1,8-naphthyridine derivatives. The coordination modes of these ligands were modified by addition of coordinating solvents such as water into the ethanolic reaction media. Under these conditions 1,8-naphthyridine (napy) moieties act as monodentade ligands forming unusual [Ru(CO)(2)Cl-2(eta(1)-2-phenyl-1,8-naphthyridine-kN)(eta(1)-2-phenyl-1,8-naphthyridine-kN ')] complexes. The reaction was reproducible when different 2-phenyl-1,8-naphthyridine derivatives were used. On the other hand, when dry ethanol was used as the solvent we obtained complexes with napy moieties acting as a chelating ligand. The structures proposed for these complexes were supported by NMR spectra, and the presence of two ligands in the [Ru(CO)(2)Cl-2(eta(1)-2-phenyl-1,8-naphthyridine-kN)(eta(1)-2-phenyl-1,8-naphthyridine-kN ')] type complexes was confirmed using elemental analysis. All complexes were tested as catalysts in the hydroformylation of styrene showing moderate activity in N,N '-dimethylformamide.