DBU-catalyzed condensation of metal free and metallophthalocyanines containing thiazole and azine moieties: Synthesis, characterization and electrochemical properties

Schiff base that contains carbothioamide moiety, substituted thiazole derivative, novel phthalonitrile compound and its corresponding metal free and metal phthalocyanines (Zn(II), Ni(II), Co(II) and Cu(II)) were synthesized and characterized for the first time. The solubility of these novel phthalocyanines were high in organic solvents and they did not aggregate in chloroform within the concentration range of 1.6 × 10−5–4 × 10−6 M. Electrochemical properties of the phthalocyanines have been examined by cyclic voltammetry, square wave voltammetry and in situ UV–vis spectroelectrochemistry on Pt in dimethylsulfoxide/tetrabutylammonium perchlorate. These measurements suggested that the compounds display subsequent ligand- and/or metal-based one-electron reduction and oxidation processes. Cobalt complex showed both metal-based and ring-based one-electron redox processes, while the other complexes displayed only ring-based one-electron couples. It was observed that the redox processes of metal free, Zn(II), Ni(II) and Cu(II) phthalocyanines are coupled by aggregation phenomenon, whereas those CoPc are not, probably due to the difference in their axial coordinating properties.