New poly(p-substituted-N-phenylpyrrole)s. Electrosynthesis, electrochemical properties and characterization

An experimental study of the electronic absorption and fluorescence spectral properties of new p-substituted-N-phenylpyrroles and their electrosynthesized polymers

“…The absence of significant shift of the absorption maximum wavelength, attributed to aromatic p-p * local electronic transitions, upon going from the monomer to the polymer spectrum, confirms that these transitions are due to the pendant un-substituted or p-substituted phenyl group(s) of the NPhPy structure, which do not undergo any significant change during the electropolymerization process [15,20]. Moreover, the increased e max values of the absorption maximum of the polymers, compared…”

“…The other electrosynthesized polymers were not enough soluble in DMF to investigate their electronic spectra in solution [15]. We observed that the absorption spectra shape of available polymers was comparable to that of the corresponding monomers, with poorly-resolved and wider absorption bands, the maximum peak wavelength being very weakly shifted relative to the monomer (Dk max = À6 to +7 nm, according to compound), as can be seen in Table 1 and Fig.…”

“…The corresponding polymers, namely (poly(MeOPhPy), poly(HOPhPy), poly(ThPhPy), and poly(PhDPy) were electrochemically synthesized by using the cyclic voltammetric method or the galvanostatic mode (current density J = 0.125 mA/cm 2 , with electrolysis time t = 1 min) in 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF 6 ) dry acetonitrile solutions containing 10 À2 M of the respective monomers, as previously described [15]. DMF (HPLC grade), DMSO (HPLC grade), acetonitrile (analytical grade) and TBAPF 6 (analytical grade) were purchased from SigmaAldrich.…”

“…These very weak red-shift values of the excitation and emission fluorescence spectra, observed upon going from the monomers to the polymers, might be explained by the fact that the molecules bearing the phenyl groups -the main fluorophore moieties -underwent very small modifications in their organization, relative position or conformation. Moreover, since they were not involved in the coupling reactions, the phenyl groups were not affected by any change during the electropolymerization process, and constituted pendant groups grafted on the polymer polypyrrolic chain [15,20]. In these conditions, there was probably no significant increase of the conjugation in the polymer S 1 state relative to the corresponding monomer, which produced a very weak red-shift of the polymer excitation and emission spectra relative to the monomer ones.…”

“…The interest of these N-functionalized pyrrole derivatives is that the functional groups can be used to fine tune the monomer and polymer physicochemical properties, and can provide anchoring points for post-modifications of the polymer. With this aim in mind, we have synthesized and characterized new p-substituted N-phenylpyrroles (N-PhPys), possessing different functional groups, such as hydroxyl, methoxy, thienyl and pyrrolyl substituents [14], and we have performed the electrochemical synthesis of the corresponding poly(p-substituted N-PhPy)s, determined their electrochemical properties and elucidated their molecular structure [15]. In recent, analogous studies of other research teams, N-functionalized dithienylpyrrole derivatives have been prepared and electropolymerized, leading to electroactive polymer films [16,17].…”