ASIAN JOURNAL OF CHEMISTRY ASIAN JOURNAL OF CHEMISTRY http://dx.doi.org/10.14233/ajchem.2014.16351 INTRODUCTION Pyrrole is one of the most used heterocyclic compounds because of the increasing interest which it arouses regarding medicnal chemistry, organic synthesis and chemistry of materials 1-7 . Consequently, various synthesis procedures were developed for pyrrole and its derivatives. Among these proce- dures, we can quote the following classic methods: (i) Hantzsch reaction 8,9 , which allows one to obtain pyrrole from the reaction between α-chloromethyl ketone, β-ketoester and ammonia water. (ii) Knorr reaction 10-14 , leading to pyrrole by reaction between α-aminoketone and β-ketoester. (iii) Paal Knorr reaction 15 which allows to obtain pyrrole by condensation of 2,5-dimethoxytetrahydrofuran and one primary amine. The interest of monomers stemming from these diverse modes of synthesis made of the chemistry of materials a much widened domain where organic chemists, electrochemists and Synthesis and Electropolymerization of New Phenylene-Substituted Dipyrridyls: Electrochemical and Spectroscopic Characterization ABDOU KARIM DIAGNE DIAW 1 , MODOU FALL 1,* , DIARIATOU GNINGUE-SALL 1 , JEAN-JACQUES AARON 2 and ABDERRAHIM YASSAR 3 1 Laboratoire de Chimie Physique Organique et d'Analyses Environnementales (LCPOAE), Département de Chimie, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, BP 5005, Dakar-Fann, Sénégal 2 Université Paris-Est, Laboratoire Géomatériaux et Environnement (EA 4508), UPEMLV, 77454 Marne-la-Vallée, France 3 LPICM (UMR 7647), Ecole Polytechnique, Route de Saclay, 91128 Palaiseau, France *Corresponding author: E-mail: modou.fall@ucad.edu.sn Received: 13 September 2013; Accepted: 8 January 2014; Published online: 1 September 2014; AJC-15835 The present paper sets out the synthesis and electropolymerization process of 1,1'-phenylenedipyrridyl and 1,1'-diphenylenedipyrridyl. These compounds are prepared by Clauson-Kaas methods with 35 or 71 % yield and characterized. UV-visible electronic absorption spectra and electrochemical methods were used to examine the effects of the electronic π-system extension in 1,1'-phenylenedipyrridyl and 1,1'-diphenylenedipyrridyl structures on the monomer properties relative to N-phenylpyrrole. Also, 1,1'-phenylenedipyrridyl and 1,1'-diphenylenedipyrridyl were electropolymerized on platinum electrode by anodic oxidation in 0.1 M tetrabutylammonium hexafluorophosphate (Bu4NPF6) acetonitrile or dichloromethane solutions and characterized by electrochemical and spectroscopic techniques. The electronic π-system extension effects on the poly(1,1'-phenylenedipyrridyl) physico-chemical properties and structure were investigated by cyclic voltammetry, FT-IR, UV-visible and XPS spectroscopy and scanning electron microscopy (SEM). Cyclic voltammetry of the poly(1,1'-phenylenedipyrridyl) films indicated a good redox behaviour and an improvement of the electrochemical properties. FT-IR spectral studies indicated a linear structure of this polymer with 2, 5 coupling on the pyrrole ring. SEM analysis showed that polymer film morphology changed between the oxidized and reduced states. The solid-state UV-visible spectra of the poly(1,1'- phenylenedipyrridyl) films on ITO were characterized by a significant red-shift of the absorption maximum, as compared to poly(1,1'- phenylenedipyrridyl) film. Moreover, the very low amount of poly(1,1'-diphenylenedipyrridyl) film obtained during the electropolymerization process and electrochemical studies of electrosynthesized poly(1,1'-diphenylenedipyrridyl) showed that the polymer properties modulated by extension of the monomer electronic π-system can be limited by steric effects. Keywords: Synthesis, Phenylpyrrole and derivatives, Electropolymerization, Electrocatalytic effect. photochemists go alongside 17-19 . This enthusiasm is partly related to the possibility of modifying the monomeric unit by grafting of numerous chemical functions, which often leads to a modification of the various properties 20-22 . To this optimi- zation is added the possibility of polymerizing these monomers in various media (organic, micellar, etc.) by means of several techniques (electrochemical, chemical, etc.) and, finally, of utilizing the obtained polymers for several applications. In previous works, the authors studied the impact of the electrosynthesis environment and the electrocatalytic effect of pyrrole which has a lower oxidation potential on the N- phenylpyrrole (N-PhPy) 24-28 electropolymerization process. So, it turned out that the presence of small amounts of pyrrole and the optimization of the environment could lead to an improve- ment of the electrosynthesized poly(N-phenylpyrrole) physico- chemical properties 26,27 . We showed that the use of micellar media for the electropolymerization of the N-phenylpyrrole Asian Journal of Chemistry; Vol. 26, No. 18 (2014), 5973-5980