Far-infrared studies of Cu(II)—1-(2 pyridylazo)-2-naphthol complexes by metal isotope technique

The metal isotope technique is applied to the investigation of the metal—ligand bands in the i.r. spectra of complexes of type: Cu(PAN)X and Cu(PAN)2 where X = Cl, Br and PAN symbolizes 1-(2-pyridylazo)-2-naphthol. For the Cu(PAN)Cl complex, bands at 337, 274 and 196 cm−1 were assigned to the CuO, CuNpy and CuNazo stretching vibrations, respectively. Two CuCl stretching vibrations have been found at 298 and 236 cm−1. The spectrum indicates that in the Cu(PAN)2 complex, PAN acts as a bidentate ligand as only CuO and CuNazo bonds are formed.