Experimental and Theoretical Investigations of an Electrochromic Azobenzene and 3,4-Ethylenedioxythiophene-based Electrochemically Formed Polymeric Semiconductor.

An electrochromic material based on azobenzene and 3,4-ethylenedioxythiophene (EDOT) semiconducting layer was electrochemically deposited on an indium tin oxide coated glass electrode. Chemical synthesis of the azobenzene and EDOT-based chromophore (DAE) and electrochemical formation of its corresponding polymer (pDAE) are reported. The electrochromic properties of the synthesized polymer pDAE were investigated by electrochemical and spectroelectrochemical methods. pDAE exhibited an optical bandgap of 1.82 eV and three distinct colored states in its reduced, neutral, and oxidized forms. The pDAE polymer showed 44 % optical contrast at 710 nm between its reduced and oxidized states and a fast electrochromic switching time of 1.0 s. The frontier molecular orbitals, Raman shifts, and semiconducting properties of this electrochromic polymer were evaluated by density functional theory calculations. The optical absorption bands of the polymer charged states were assigned and investigated.

Comparative Investigation of Peripheral and Nonperipheral Zinc Phthalocyanine-Based Polycarbazoles in Terms of Optical, Electrical, and Sensing Properties.

In this study, nonperipherally alkyl-linked carbazole conjugated novel zinc(II) phthalocyanine was synthesized by cyclotetramerization reaction of 6-(9 H-carbazol-9-yl)hexane-1-thiol and 3,6-bis(tosyloxy) phthalonitrile in a one-step reaction. Optical, electrical, and sensing properties of this super structured polycarbazole obtained by electropolymerization are compared with peripherally alkyl-linked polycarbazole-based zinc(II) phthalocyanine. It has been found that the attachment of alkyl-linked carbazoles to the phthalocyanine molecule in either peripheral or nonperipheral positions has a great effect on the optical and electrical properties and sensing ability of the resulting polycarbazole derivatives. P(n-ZnPc) has the highest electrochromic contrast (70.5%) among the derivatives of zinc(II) phthalocyanines in the literature. In addition to these, the sensor platform has been successfully established, and analytical optimizations have been carried out. When the sensors prepared with zinc(II) phthalocyanine are examined, it was specified that the n-ZnPc- co-TP/GOx was ranked first in the literature with high sensor response and stability. As a result, by changing of the peripheral and nonperipheral position of phthalocyanines, their physical properties can be tuned to meet the requirements of desired technological application.

Zinc(II) phthalocyanine fused in peripheral positions octa-substituted with alkyl linked carbazole: Synthesis, electropolymerization and its electro-optic and biosensor applications.

Zinc(II) phthalocyanine fused in peripheral positions octa-substituted with alkyl linked carbazole has been prepared by cyclomerization reaction of 4,5-bis(6-carbazole-9-yl-hexylsulfanil)phthalonitrile in the presence of anhydro Zn(II) acetate and a strong organic base (DBU). Synthesis steps were optimized and higher efficiency synthesis was achieved. The purpose of combining of carbazole moieties with phthalocyanine on the peripheral position is to enhance some properties such as photo and electrochemical properties because of strong electron-donating properties of carbazole group. This molecule has been electrochemically polymerized and the electrical and optical properties of the resulting conductive polymer have been investigated. Amperometric detection was carried out following oxygen consumption at -0.7V vs. the Ag reference electrode in phosphate buffer (50mM, pH 6.0). The novel biosensor showed a linear amperometric response for glucose within a concentration range of 0.05mM to 1.5mM (LOD: 0.024mM). This result shows that modification of the proposed biosensor by copolymerization have provided to give perfect response to different glucose concentrations. Because of its superior spectral and electrochemical properties and contained zinc metal which can act as a mediator during biochemical reactions, this material has been used as a glucose biosensor platform to detection for real samples.

Enhancing biosensor properties of conducting polymers via copolymerization: Synthesis of EDOT-substituted bis(2-pyridylimino)isoindolato-palladium complex and electrochemical sensing of glucose by its copolymerized film.

1,3-Bis(2-pyridylimino)isoindoline derivative bearing 3,4-ethylenedioxythiophene (EDOT-BPI) and its palladium complex (EDOT-PdBPI) were synthesized and characterized by FT-IR, 1H NMR, 13C NMR, UV-Vis spectroscopies and via mass spectrometric analysis. Polymerization of EDOT-PdBPI and copolymerization with 4-amino-N-(2,5-di(thiophene-2-yl)-1H-pyrrol-1-yl)benzamide (HKCN) were carried out by an electrochemical method. In addition, P(EDOT-PdBPI-co-HKCN) modified graphite rod electrode was improved for amperometric glucose sensor based on glucose oxidase (GOx). In this novel biosensor matrix, amino groups in HKCN were used for the enzyme immobilization. On the other hand, EDOT-PdBPI used to mediate the bioelectrocatalytic reaction. Amperometric detection was carried out following oxygen consumption at -0.7V vs. the Ag reference electrode in phosphate buffer (50mM, pH 6.0). The novel biosensor showed a linear amperometric response for glucose within a concentration range of 0.25mM to 2.5mM (LOD: 0.176mM). Amperometric signals at 1mM of glucose were 17.9µA under anaerobic conditions. Amperometric response of the P(EDOT-PdBPI-co-HKCN)/GOx electrode decreased only by 13% within eight weeks. The P(EDOT-PdBPI-co-HKCN)/GOx electrode showed good selectivity in the presence of ethanol and phenol. This result shows that, modification of the proposed biosensor by copolymerization of amine functionalized monomer, which is indispensable to the enzyme immobilization, with palladium complex bearing monomer, which is mediate the bioelectrocatalytic reaction, have provided to give perfect response to different glucose concentrations.

Smart windows application of carbazole and triazine based star shaped architecture.

A novel triazine-based, star shape and electroactive monomer, 2,4,6-tris(2-(9H-carbazol-9-yl)ethoxy)-1,3,5-triazine (TCZ) which contains 2,4,6-trichloro-1,3,5-triazine as the core and 2-(9H-carbazol-9-yl)ethanol as the arms, was successfully synthesized. After electrochemical polymerization of the TCZ monomer, called PTCZ, the polymer shows superior optoelectronic and thermal properties due to its unique three-dimensional shape and highly-branched structure in comparison with linear analogues. Electrochromic studies exhibited that PTCZ has turquoise color in the oxidized state and is transparent in the neutral state. Due to the fact that the redox color characteristics of PTCZ are indispensable for smart windows, a PTCZ-based electrochromic device was formed with PEDOT as complementary coloring material. A potential range of -1.5 to +1.8 V was determined to be suitable for operating the PTCZ/PEDOT device between transparent and blue colors. Characterizations of the device were performed in term of switching times, optical contrast, optical memory and redox stability.

A soluble and fluorescent new type thienylpyrrole based conjugated polymer: optical, electrical and electrochemical properties.

Recently, increased attention has been focused on the synthesis of soluble and processable conducting polymers due to interest in their potential application. For this purpose a new type electroactive 2,5-di(2-thienyl)pyrrole derivative was synthesized and its novel solution-processable and fluorescent polymer, namely poly(N-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)-3,4,5-tris(dodecyloxy)benzamide) (P(TPDOB)), was electrochemically synthesized. Characterization of the monomer and the polymer was performed by (1)H-NMR, (13)C-NMR, cyclic voltammetry, and UV-vis and fluorescence spectroscopy. This soluble polymer has very well-defined and reversible redox processes in the acetonitrile-lithium perchlorate (ACN/LiClO4) couple. Moreover, P(TPDOB) shows multielectrochromic behavior: blue in the oxidized state, caesious in the intermediate state and greenish in the neutral state. Also the copolymer consists of EDOT and TPDOB was synthesized by cyclic voltammetry. A copolymer film has superior electrochromic and electrical properties when compared with a homopolymer. Furthermore, the fluorescence features of the monomer and the polymer were investigated. Although the monomer is a violet light emitter, its polymer is a yellow light emitter. Synthesis of this new type solution-processable and fluorescent conducting polymer is an alternative to the conventional synthesis of soluble conducting polymers which allows the direct application of the conductive polymer to any desired surface for potential technological applications.