Functionalized Pyrrole Monomers Research Articles

Sensitive and Selective Recognition of Teriflunomide Based on Molecularly Imprinted Electrochemical Sensor Via Newly Synthesized Functionalized Pyrrole Monomer: Pyrrole Histidine

Sensitive and Selective Recognition of Teriflunomide Based on Molecularly Imprinted Electrochemical Sensor Via Newly Synthesized Functionalized Pyrrole Monomer: Pyrrole Histidine

Electrosynthesis of polypyrrole nano/micro structures using an electrogenerated oriented polypyrrole nanowire array as framework

The purpose of this paper is to show that it is possible to increase the diameter and length of the nanostructures of a framework formed of oriented polypyrrole nanowires that has been prepared by a templateless electrochemical method based on the use of a pyrrole solution containing a high concentration of weak-acid anion and a low concentration of non-acidic anion. The dimensions of the initial nanowires are increased by performing an additional electrosynthesis in a ‘classical’ monomer solution. Depending on the polarization time of this last synthesis (a few tens of seconds), wires with various diameters, from one hundred up to several hundred nanometers, are obtained. In addition to the variation of the nanowire size, these findings confirm, as outlined in the reaction mechanism we have proposed, that the base of the nanowires is surrounded by a thin non-conductive polymer i.e. by an overoxidized polypyrrole film. Actually this paper shows a proof-of-concept. Indeed one can imagine that the second polymeric electrodeposit could be performed using an organic monomer solution, using functionalized pyrrole monomer to fabricate a biosensor having large specific area, and/or using anions which could be drugs.

Synthesis and electropolymerization of 3,4-substituted quinoxaline functionalized pyrrole monomer and optoelectronic properties of its polymer

We synthesized a new electroactive pyrrole functionalized monomer; 2-butyl-5,12-dihydro-2H-pyrrolo[3′,4′:2,3][1,4]dioxocino[6,7-b]quinoxaline (BuDQP) where β-positions of the pyrrole ring are blocked. With the help of this strategy, formation of α–β linkages during polymerization was prevented, resulting in a more regiochemically defined material. Characterization of newly synthesized compounds was performed by FTIR, GC–MS, 1H NMR, 13C NMR techniques and elemental analysis. Polymerization and copolymerization of BuDQP and characterization of the resulting polymers were also performed. Spectroelectrochemical investigations, switching abilities, colorimetry studies and stability experiments were performed on both for polymer and copolymer. Spectroelectrochemical analysis of P(BuDQP) reflected electronic transitions at 328nm (π–π* transition) and 500nm (polaron bands) with an electronic band gap of 2.30eV, while copolymer (P(BuDQP-co-Py)) revealed electronic transitions at 346nm (π–π* transition) and 518nm (polaron bands) with an electronic band gap of 2.24eV. Colorimetry studies revealed that P(BuDQP) has only two colors (blue and yellow) whereas copolymer film has six different colors in its oxidized and neutral states.

Photo switchable pendant furyl and thienyl fulgimides containing polypyrroles

We report the new pendant furyl and thienyl fulgimides photochromic switch bearing polypyrroles. The functionalized pyrrole monomers synthesized and structures are ascertained by NMR and mass spectral techniques. The yield of fulgides and fulgimides are improved by using trifluoroacetic anhydride (TFA) as a dehydrating agent. The photo-switching properties of fulgimides monomers are explained by electronic structures of HOMO–LUMO of the monomers using Gaussian 03 packages. The electro-active polymer films deposited on indium tin oxide (ITO) electrodes are characterized by cyclic voltammetry and atomic force microscopy (AFM). The electrochemically formed thin films undergoes photo-switching between open and closed state of fulgimides moiety. The photo-switching properties of the polymer films have been confirmed by UV/vis spectroscopy. Though the films are photochemically stable, their mechanical stability with respect to adhesion to electrode is found to be sensitive to the solvent and electrode material.

Photochromic switchable pendant indolyl fulgimide polypyrrole

The photochromic switchable 2-indolyl fulgimide functionalized pyrrole monomer is synthesized and ascertained by spectroscopic techniques. The absorption and emission band of monomer due to intramolecular charge transfer (ICT) state exhibit typical bathochromic shift from nonpolar to polar solvents. The molecular geometry and bandgap energy of monomer in open form as well as closed form are calculated by B3LYP/6-31 G (d) with Gaussian 03 program package. The functionalized pyrrole monomer is electropolymerized by cyclicvoltammetric method on an electrode. The polymer indicated a completely reversible photoswitching between two isomers of open and closed form 2-indolyl fulgimide moiety, which are stable over many cycles of operation by UV/visible light sources. The closed form of polymer exhibit fluorescence quenching attributed to the energy transfer from conductance band of polypyrrole to closed form of 2-indolyl fulgimides unit. This fluorescence quenching system controls the conductance of conducting polymer in molecular electronics and molecular switches.

Electrochemically Fabricated Pyrrole Copolymer Thin Films and Their Electroactivity in Neutral Aqueous Solution

The functionalized pyrrole copolymers were fabricated by electropolymerization of pyrrole (Py) and functionalized pyrrole monomers, pyrrole-3-carboxylic acid (P3C) and 4-(3-pyrrole) butyric acid (PBA). The electrochemical behavior and doping/dedoping properties of the obtained copolymer thin films were investigated by cyclic voltammetry (CV) in neutral phosphate-buffered saline (PBS) solution. Moreover, the functionalized pyrrole copolymer films were characterized by UV-vis absorption spectroscopy and atomic force microscopy (AFM). The obtained copolymer thin films showed good stability and electroactivity in neutral PBS solution. The presented functionalized pyrrole copolymer thin films may possess potential applications to study in various systems of the biosensors.

Oxidoreductase Catalyzed Polymerization of 3-Methylpyrrole

A one-pot, environmentally friendly enzymatic method is described for the synthesis a polypyrrole derivative, poly(3-methylpyrrole) (poly(3-MP)) in an aqueous solvent system. The enzyme, soybean peroxidase (SBP), was shown to successfully polymerize the beta functionalized pyrrole monomer. The resulting polymer was semiconducting, thermally stable, and exhibited bipolaron absorptions when synthesized in the presence of poly(sodium 4-styrenesulfonate) (PSS). Polymers synthesized in the presence of 10-camphor sulfonic acid (CSA) were found to exhibit slightly higher conductivity values, but were less thermally stable compared to poly(3-MP) polymerized in the presence of PSS. This work should stimulate further interest in expanding the use of enzymes as catalysts for the polymerization of other pyrrole derivatives, as well as other classes of conjugated polymers.

A Substrate-Integrated and Scalable Templated Approach Based on Rusted Steel for the Fabrication of Polypyrrole Nanotube Arrays

We report here a facile, generalizable, and entirely scalable approach for the fabrication of vertically aligned arrays of Fe(2)O(3)/polypyrrole core-shell nanostructures and polypyrrole nanotubes. Our "all electrochemical" approach is based on the fabrication of α-Fe(2)O(3) nanowire arrays by the simple heat treatment of commodity low carbon steel substrates, followed by electropolymerization of conformal polypyrrole sheaths around the nanowires. Subsequently, electrochemical etching of the nanowires yields large-area vertically aligned polypyrrole nanotube arrays on the steel substrate. The developed methodology is generalizable to functionalized pyrrole monomers and represents a significant practical advance of relevance to the technological implementation of conjugated polymer nanostructures in electrochromics, electrochemical energy storage, and sensing.

Effects of polypyrrole modified electrode functionalization on potentiometric pH responses

Two functionalized polypyrrole films, poly(11-N-pyrrolylundecanoic) acid and poly(N-undecylpyrrole), were used as sensitive layers for pH sensors. The functionalized pyrrole monomers were first synthesized before carrying out their electropolymerization onto non-oxidizable electrodes. The deposits were characterized by SEM imaging, XPS and PM-IRRAS to study surface structure and composition. Poly(11-N-pyrrolylundecanoic) acid coating yielded very promising results as sensitive layer in pH sensors. Indeed, the potentiometric responses from pH 4.0 to 9.0 appeared linear, reversible, stable in time over a period of 1 month and highly selective for H + ions. This behavior was attributed to carboxylic acid groups which are sensitive to proton concentration changes. This was confirmed by the fact that poly(N-undecylpyrrole) film led to potentiometric responses being pH dependent only from pH 6.0 to 9.0 with low sensitivity. Poly(11-N-pyrrolylundecanoic) acid is thus promoted to be used as sensitive layer in pH sensors.

Electrochemical polymerization of imidazolum‐ionic liquids bearing a pyrrole moiety

AbstractA series of imidazolium‐based ionic liquid monomers bearing a terminal pyrrole moiety were synthesized and electrochemically polymerized. It is found that the polymerizability of the synthesized ionic liquids is strongly dependent on the type of the counteranions. Although bromide monomer is not polymerizable, well‐defined polymeric films can be formed on various substrates in the cases of flour‐containing anions (BF4−, PF6−). The performed characterizations show that all resulting polypyrrole films are electroactive, and the imidazolium‐based ionic liquid moieties are correctly incorporated in polymer films during the electropolymerization process. This work not only provides a facile new method to immobilize ionic liquids on solid surface. Interestingly, without use of any template unique “knit” morphology and nanostructure, even hierarchical structures could also be produced by the electropolymerization of these new functionalized pyrrole monomers. We found that the properties of the pendant ionic liquid units on the surface of the formed polymer films preserved, and by simple anion exchange their surface energy and tension could be easily tuned without loss of the electrical, optical properties, and morphology of the polypyrrole films. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4151–4161, 2008

Synthesis, Characterization and Electrochemical Polymerization of a Ru2+ Functionalized Pyrrole Monomer

AbstractA ruthenium(II) functionalized pyrrole, Ruthenium‐bis‐N,N′‐(2,2′‐bipyridyl)‐N‐(pyridine‐4‐ylmethyl‐(8‐pyrrole‐1‐yl‐octyl)amine)chloride, 1, has been synthesized and characterized by spectroscopic (UV/vis, 1H NMR) techniques and cyclic voltammetry. In solution 1 gave a redox couple associated with the Ru3+/2+ redox system and an irreversible wave associated with the oxidation of the covalently linked pyrrole moiety. What is believed to be homopolymerization, redox active surface films of 1 have been prepared by electrooxidation of the monomeric solution. The resulting polymeric film exhibited clear redox activity associated with the incorporated Ru2+ redox centre, which is covalently linked ruthenium centre to the pyrrole moiety in 1. The effect of surface coverage upon the electrochemical behavior of the deposited films has been undertaken. Preliminary investigations into the homogeneous charge transport dynamics of the polymeric film deposited onto platinum microelectrodes has been undertaken. Copolymerization with 3‐methylthiophene was carried out and a clear ruthenium response was seen. Films were formed by both cyclic voltammetry and chronocoulometry and studied. Various ratios were attempted but the ideal was found to be 52 : 5 mmol (3‐methylthiophene: 1).

Label-free detection of DNA hybridization based on a novel functionalized conducting polymer

A new functionalized pyrrole monomer, 3-pyrrolylacrylic acid (PAA) was synthesized. It was used to prepare a copolymer with pyrrole, poly(Py- co-PAA), which was investigated by reflective FT-IR, UV–vis spectroscopy and cyclic voltammetry. A label-free DNA sensor was prepared based on a poly(Py- co-PAA) film. Hybridization with complementary and non-complementary DNA targets was studied by electrochemical impedance spectroscopy. Results show a significant increase in the charge-transfer resistance upon addition of complementary target. The impedance spectra were analyzed by using a modified Randles and Ershler equivalent circuit model. The change in charge-transfer resistance that was used as an index of sensor response was found to be linear with logarithmic target concentration in the range of 2 × 10 −9 to 2 × 10 −7 M. The detection limit was 0.98 nM.

Preparation and characterization of covalently bonded biopolymer-polypyrrole hybrid materials

The synthesis of biopolymer-polypyrrole hybrid materials that can possess electrical conducting has been the focus of our laboratory. To date, we have only obtained intimate blends that at best, display ionic bonding interactions. In this paper we report on the preparation of biopolymer-polypyrrole hybrid materials with covalent bonding between the two polymer chains. This has been achieved by preparing several functionalized pyrrole monomers, followed by covalently bonding of these monomer to the biopolymer and finally, polymerizing the pyrrole monomer. The pyrrole monomers used were 4-(3-pyrrolyl)oxobutyric acid, 4-(3-pyrrolyl)butyric acid, 3-(3-pyrrolyl)propylamine and the biopolymers were collagen and chitosan. FTIR data show the presence of covalent bonding between the two polymer chains.