Synthesis and electrochemical properties of phthalocyanines with four 8-quinolinoxy-substituents

A metal-free phthalocyanine and its cobalt(II) and copper(II) phthalocyanate complexes were prepared by cyclotetramerization of 4-(8-quinolinoxy)phthalonitrile. The new compounds were characterized by elemental analyses, ¹H-n.m.r., i.r. and u.v.–vis. spectral data. Electrochemical measurements indicated that CoPc had two metal based and two ligand based redox couples, while H₂Pc and CuPc showed four ligand based redox couples. For all complexes, linear variation of the peak current of the first reduction peak (I _pc) with scan rate () indicated the adsorption of the complexes to the electrode surface.