Synthesis of new electroactive polymers by ion-exchange replacement of Mg(II) by 2H(+) or Zn(II) cations inside Mg(II) polyporphine film, with their subsequent electrochemical transformation to condensed-structure materials

It has been demonstrated that the treatment of the magnesium polyporphine of type I, pMgP-I, by trifluoroacetic acid in acetonitrile may be used to replace initial central Mg(II) cations inside the monomeric macrocycle units by protons, to get a new electroactive polymer, ``free-base polyporphine of type I'', pH(2)P-I. In its turn, these inserted protons may be replaced by Zn(II) cations via the film treatment with zinc acetate in organic solvent, to get another new electroactive polymer, ``zinc polyporphine of type I'', pZnP-I. These changes of central ions inside monomer units manifest themselves by characteristic modifications of their electroactive properties as well as of UV-visible and IR spectra. Similar to the magnesium polyporphine of type I, pMgP-I, studied in our previous paper (Electrochim. Acta, 2010, 55, 6703) both new polymers are subject to an irreversible electrooxidative transformation into the corresponding polyporphines of type II, pH(2)P-II and pZnP-II. All these polyporphines of type II demonstrate a very broad range of their redox activity, without any potential interval of non-electroactivity. It means that they represent electroactive polymers with a zero-width band gap in the neutral state of the polymer and the Fermi level is located into a broad electronic band for a wide range of the positive and negative oxidation states. Expected molecular structures of all these polymers are discussed. (C) 2013 Elsevier Ltd. All rights reserved.