CONICET | Buscador de Institutos y Recursos Humanos

Tetrapyrrolic-based molecules and polymers are very important compounds due to their fundamental roles as light absorbers and redox centres in biologic systems and also because of their numerous applications in practical devices.1 Most of these applications are based in both, the redox and light-absorbing properties of porphyrins and phthalocyanines2, and in their capacity of to convert the light energy into an electrochemical potential.3 In several cases, the incorporation of tetrapyrrolic centres into conducting polymers is very convenient for device fabrication and application, because it confers an additional stability to the organic system and also could improve the diffusion and migration of the electrical or photo-generated charge carriers to and from a base contact electrode.4 In this frame, dendrimeric arrangements containing porphyrins are very interesting architectures due to the effects originated by the encapsulation of the tetrapyrrolic core in the interior of the hyperbranched structure.5 However, unfortunately in most of the cases dendrimer synthesis is difficult, expensive and time-consuming, often due to steric hindrance and solubility problems in the sequential synthesis steps.6 As consequence more easy and effective methods for to encapsulate porphyrins in a way that preserves their functional properties afforded by dendritic shells are needed.7 On the other hand, it is know the versatility of electrochemical synthesis methodologies for obtaining organic polymers as films over electrode surfaces that can be used as building blocks in the fabrication of functional devices.8 In the case of porphyrin derivatives the electrochemical polymerization usually is carried out through the oxidative coupling of peripheral substituents, meanwhile the tetrapyrrolic macrocyclic ring remains unaltered.9 In this work we have synthesized a peripherally Carbazole functionalized dendrimeric starburst monomer containing electron acceptor 1,2,3-Triazole in the branches and electron donor Zn(II) porphyrin Core. The Porphyrin holds tetrafluoride aril substituents connecting the triazole moieties. The electrochemical oxidation of the Carbazole terminal groups allows the electrochemical polymerization over Pt and indium tin oxide electrodes of the fully π-conjugate dendrimeric monomer producing a novel electro-active polymeric film. The versatile electropolymerization methodology allows the generation of thin films of hyperbranched macromolecules with good electrical conductivity, reversible electrochemical processes and electrochromic properties.