Novel phthalocyanines bearing 4-(2-isopropylphenoxy) groups: Synthesis, characterization, electrochemical and in-situ spectroelectrochemical properties

Abstract

In this study, 4-(2-isopropylphenoxy)phthalonitrile (3) was prepared via a substitution reaction between 2-isopropylphenol (1) and 4-nitrophthalonitrile (2). Then, peripherally tetra 2-isopropylphenoxy substituted zinc(II) (4) and cobalt(II) (5) phthalocyanines were obtained via a cyclotetramerization reaction between phthalonitrile (3) and related metal salt. The structural characterization of synthesized compounds were completed via FT-IR, ¹HNMR , UV–Vis and MALDI-TOF mass data. Electrochemical and spectroelectrochemical measurements were performed to determine the potential of novel phthalocyanines to be used in electrochemical applications. While the cobalt(II) phthalocyanine (5) displayed one metal-based reduction, two ring-based reductions and one metal and ring-based oxidation; zinc(II) phthalocyanine (4) showed three ring-based reductions and one ring-based oxidation reaction. In addition, it was determined that electron-releasing isopropyl phenoxy group affected half-wave peak potentials of complexes and the Q band positions. Diffusion-controlled, reversible and multi-electron transfer abilities of the zinc(II) (4) and cobalt(II) (5) phthalocyanines showed that they have redox richness for can be used in optical technological applications.