Deprotonation or protonation: The coordination properties, crystal structures and spectra of cobalt (II) complex with 1-(2-pyridylazo)-2-acenaphthequinol ligand

Abstract The reaction of 1-(2-pyridylazo)-2-acenaphthequinol (PAAL) with cobalt acetate in CHCl 3 gave the complex of Co(PAAL-H) 2 (1), and (PAAL + H) 2 [CoCl 4 ]·2H 2 O (2) was isolated in the same system with ultraviolet light irradiation. Structures of both compounds were determined by X-Ray diffraction. The PAAL ligand was deprotonated in 1 , but it further protonated on N position at pyridine group in 2 and form cations. The spectra of these two compounds were also studied, as well as the fluorescence properties. Also, the redox property of 1 was preliminary investigated by cyclic voltammogram.