Hydrolysis of 4-(4-oxopentan-2-ylideneamino)benzoic acid and in-situ formation of nickel(II), zinc(II) and cadmium(II) complexes of 4-aminobenzoic acid

Metal(II) acetates of nickel, zinc and cadmium facilitate hydrolysis of 4-(4-oxopentan-2-ylideneamino)benzoic acid (iminocarb). In the case of nickel a dinuclear iminocarb complex is proposed as intermediate species to form nickel complex of 4-aminobenzoic acid (Haben). The nickel complex formed from hydrolysis has a composition [Ni(O2CCH3)2(Haben)2(H2O)2]·2H2O. In this complex, the nitrogen atoms of the 4-aminobenzoic acid ligands coordinate to nickel ion and the benzoic acid end of the ligands remain free. A five coordinate [Zn(aben)2(py)(H2O)] complex is obtained from a similar reaction of iminocarb with zinc(II) acetate followed by reaction with pyridine (py). On the other hand the reaction of iminocarb with cadmium(II) acetate forms a coordination polymer [{Cd(aben)2(H2O)}·H2O]n.

Hydrolysis of 4-(4-oxopentan-2-ylideneamino)benzoic acid is facilitated by various metal acetates such as nickel(II) acetate, zinc(II) acetate and cadmium(II) acetate. The coordination effect in the hydrolysis is presented.Figure optionsDownload as PowerPoint slideHighlights
► Hydrolysis of 4-(4-oxopentan-2-ylideneamino)benzoic acid is facilitated by metal acetates.
► Coordination effect on formation of different 4-aminobenzoate complexes of Ni, Zn and Cd is discussed.
► A dinuclear intermediate is proposed as reaction intermediate for nickel(II) mediated hydrolysis.
► A five-coordinate zinc(II) 4-aminobenzoate complex is characterized.