Pinar Camurlu

Multichromic, ferrocene clicked poly(2,5-dithienylpyrrole)s

Herein, we report the synthesis of a novel, click functionalized 2,5-dithienylpyrrole (SNS-Fc) for the first time. Ferrocene was employed as an anchored unit because of its well-known physical and redox properties. SNS-Fc was electrochemically polymerized and electrochromic properties of the resulting polymer were investigated in detail. In addition, electrochemical copolymerization of SNS-Fc in the presence of 3,4-ethylenedioxythiophene was performed. The resulting copolymer displayed multichromic behavior ranging between orange, yellow, green and blue in different redox states. Cyclic voltammetry studies of both polymers revealed two reversible waves related to the polymer backbone and Fe II/III redox couples, while showing the typical characteristic of surface-confined structures. Our studies have shown that the redox behavior, band gap and color of poly(2,5-dithienylpyrrole) derivatives are highly dependent on anchored unit (ferrocene) and copolymerization.

A neutral state green polymer with a superior transmissive light blue oxidized state.

This report highlights the synthesis of only the second green polymer in the literature, which possesses superior properties over the first: a highly transmissive light blue color in the oxidized state with high optical contrast and excellent switching properties.

Polypyrrole derivatives for electrochromic applications

Electrochromic materials display a reversible color change upon electrochemical cycling. In the last two decades there has been increasing interest in the electrochromic properties of polypyrroles. In this article, we highlight and provide insight into the electrochromic properties of polypyrroles in terms of their structure–property relationships without the intention of providing a complete chronological order.

Dual Type Complementary Colored Polymer Electrochromic Devices Based on Conducting Polymers of Poly(hexanedioic acid bis‐(2‐thiophen‐3‐yl‐ethyl ester)

In this study, dual type polymer electrochromic devices (ECDs) based on homopolymer and copolymer of hexanedioic acid bis‐(2‐thiophen‐3‐yl‐ethyl ester) with 3,4‐ethylene dioxythiophene (EDOT) were constructed, where PEDOT functioned as the cathodically coloring layer. Spectroelectrochemistry, switching ability, stability, open circuit memory and color of the devices were investigated. Results of the kinetic studies showed these devices exhibit switching times around 1.8 s with an optical contrast of 24–25.3%. The device utilizing the homopolymer revealed color variation between yellow and blue, whereas the one with the copolymer was between orange and blue. Both devices have good open circuit memory under atmospheric conditions, which might be useful in many applications.

Synthesis and Electrochromic Properties of a Symmetric Polythiophene Derivative: Decanedionic Acid Bis‐(2‐thiophene‐3‐yl‐ether)ester and its Copolymer with Thiophene

Here we describe the electrochemical homopolymerization and copolymerization of decanedionic acid bis‐(2‐thiophene‐3‐yl‐ ether)ester (DATE) in the presence of thiophene. Tetrabutylammonium tetrafluoroborate (TBAFB) was utilized as the supporting electrolyte in acetonitrile (ACN)/borontrifloride ethylether (BFEE) solvent mixture (8:2D, v/v). Electrochemical homopolymerization of DATE and copolymerization with thiophene were studied by cyclic voltammetry (CV). Conducting polymers were characterized by Fourier Transform Infrared (FT‐IR) and Thermal Analyses. The morphologies of electrochemically synthesized P(DATE) and P(DATE‐co‐Th) thin films were analyzed by Scanning Electron Microscopy (SEM). Electrical conductivities were measured by the four‐probe technique. Spectroelectrochemical behaviors of P(DATE) and P(DATE‐co‐Th) films were investigated by UV‐Vis Spectrophotometer. Homopolymer revealed color changes between brownish yellow and blue, whereas copolymer revealed changes between orange and blue in reduced and oxidized states respectively. Switching ability of the polymers was investigated via kinetic study upon measuring the % transmittance (%T) at the maximum contrast point. Results implied that copolymerization is a valuable approach to achieve the desired electrochromic properties.

Conducting Copolymers of Random and Block Copolymers of Electroactive and Liquid Crystalline Monomers with Pyrrole and Thiophene

Block and random copolymers having 3‐methyl thienylmethacrylate and 6‐(4‐cyanobiphenyl‐4′‐oxy)hexyl acrylate moieties were utilized as precursor polymers in this study. Electrochemical copolymerizations were performed in the presence of thiophene or pyrrole in acetonitrile‐tetrabutylammonium tetrafluoroborate (TBAFB) at constant potential. The characterizations were performed by cyclic voltammetry (CV), fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermal gravimetry analysis (TGA), scanning electron microscopy (SEM), conductivity measurements. Electrochromic properties of the resultant conducting copolymers were investigated by spectroelectrochemistry and colorimetry studies. It was observed that, variation in the copolymer type or composition of the precursor polymer resulted in stern effects on surface morphology, spectroelectrochemistry, color and conductivity of the resultant graft copolymer.

Construction of ferrocene modified conducting polymer based amperometric urea biosensor

Herein, an electrochemical urea sensing bio-electrode is reported that has been constructed by firstly electropolymerizing 4-(2,5-Di(thiophen-2-yl)-1H-pyrrol-1-yl)aniline monomer (SNS-Aniline) on Pencil Graphite Electrode (PGE), then modifying the polymer coated electrode surface with di-amino-Ferrocene (DAFc) as the mediator, and lastly Urease enzyme through glutaraldehyde crosslinking. The effect of pH, temperature, polymer thickness, and applied potential on the electrode current response was investigated besides performing storage and operational stability experiments with the interference studies. The resulting urea biosensors amperometric response was linear in the range of 0.1-8.5mM with the sensitivity of 0.54μA/mM, detection limit of 12μM, and short response time of 2s. The designed bio-electrode was tested with real human blood and urine samples where it showed excellent analytical performance with insignificant interference.

Optoelectronic Properties and Electrochromic Device Application of Novel Pyrazole Based Conducting Polymers

Here we report on the synthesis and characterization of pyrazole based conducting polymers and utilization of these polymers in electrochromic devices. For this purpose, 3,5-di-thiophen-2-yl-1H-pyrazole (DThPz) was synthesized via a Knorr type reaction and it was electrochemically polymerized. The resultant homopolymer had a band gap of 2.6 eV and displayed yellow to mode beige coloration upon doping. In order to enhance the switching characteristic; electrochemical copolymerization of DThPz in the presence of 3-hexylthiophene (HTh) and N-methyl pyrrole (NMP) was performed. Spectroelectrochemistry analysis of poly(DThPz-HTh) reflected electronic transitions at 405 and 740 nm due to π– π* transition and charge carrier band formation, respectively. The polymer displayed color change from chrome yellow to blue upon doping. Poly(DThPz-NMP), on the other hand had a π– π* transition at 355 nm and formation of new transitions at around 750 nm was observed. Additionally, as an application, dual-type electrochromic devices based on both poly(DThPz-HTh) and poly(DThPz -NMP) were assembled and characterized via spectroelectrochemistry, kinetic and colorimetry studies.

Immobilization of Tyrosinase in Poly(2-thiophen-3-yl-alkyl ester) Derivatives

In this study, construction of novel biosensors for the determination of phenolic compound was performed via immobilization of tyrosinase during the electrochemical synthesis of conducting block copolymers of 2-thiophen-3-yl-alkyl ester derivatives with 3,4-ethylenedioxythiophene and synthesis of poly(3,4-ethylenedioxythiophene) (PEDOT). The resultant biosensors were characterized in terms of their maximum reaction rates, Michaelis–Menten constants (Km), temperature and pH stabilities. All the copolymer matrices represented higher reaction rates and higher Km values in comparison to both polypyrrole and PEDOT matrices and a relation between the morphology of the matrice and the kinetic parameters was observed. Biosensors maintained their activity even at temperatures as high as 80°C and could be used at pHs higher than 8 with high precision. The amount of phenolics in actual samples (red wines) was investigated using electrodes, and results were compared with those found from Folin–Ciocalteau method. Hence, the present study has proven the suitability of these copolymers to be used as polymer matrices for enzyme immobilization.

Ferrocene clicked polypyrrole derivatives: effect of spacer group on electrochemical properties and post-polymerization functionalization

Abstract In this study, novel ferrocene-functionalized N-alkyl substituted pyrrole derivatives, namely 4-ferrocenyl-1-[3-(pyrrol-1-yl)propyl]-1H-1,2,3-triazole (Py3Fc), 4-ferrocenyl-1-[4-(pyrrol-1-yl)butyl]-1H-1,2,3-triazole (Py4Fc), and 4-ferrocenyl-1-[6-(pyrrol-1-yl)hexyl]-1H-1,2,3-triazole (Py6Fc), were synthesized via click reaction and the monomers were characterized by 1H NMR, 13C NMR, FTIR, and HRMS techniques. Redox properties of the monomers were investigated by cyclic voltammetry (CV) studies. Contrary to general literature, both Py4Fc and Py6Fc were electrochemically polymerized without loss in redox activity of ferrocene group. Moreover, click chemistry was utilized in post-polymerization functionalization. For this purpose, three azide-containing polypyrroles, P(Py3N3), P(Py4N3), and P(Py6N3) were electrochemically synthesized and subjected to click reaction in the presence of ethynylferrocene. CV studies of the post-polymerization functionalized polymers revealed quasi-reversible waves, while only P(Py6-post-Fc) showed the characteristic redox behavior of both polypyrrole and ferrocene. Thus, in this study preparation of a conducting homopolymers of pyrrole having covalently bonded ferrocene units was demonstrated and effect of spacer group is investigated.