Synthesis, spectroscopic, electrochemical and spectroelectrochemical properties of metal free, manganese, and cobalt phthalocyanines bearing peripherally octakis-[4-(thiophen-3-yl)-phenoxy] substituents

Abstract

Metal free ( 2), manganese ( 3), and cobalt ( 4) phthalocyanines, which are octa-substituted at the peripheral positions with [4-(thiophen-3-yl)-phenoxy] moieties, were synthesized and electrochemical properties were reported for the first time. The complexes were characterized by elemental analysis, IR, 1H NMR, mass spectroscopy, and electronic spectroscopies. Electrochemical and spectroelectrochemical measurements exhibit that incorporation of the redox active metal ions, Co II and Mn IIIOAc, into the phthalocyanine core extends the redox richness of the Pc ring with the reversible metal-based reduction and oxidation couples in addition to the common Pc ring-based electron transfer processes. Presence of molecular oxygen in the electrolyte system causes to form π-oxo MnPc complexes, which alter the voltammetric and spectroelectrochemical responses of the complex. An in situ electrocolorimetric method has been applied to investigate the color of the electro-generated anionic and cationic forms of the complexes for possible electrochromatic applications.