A new polythiophene derivative, poly-2,3-bis(4-tert-butylphenyl)-5,8-bis(4-hexylthiophen-2-yl)quinoxaline PHTQ was synthesized by both chemical and electrochemical polymerization and its electrochemical properties were reported. The monomer was electrochemically polymerized in the presence of tetrabutylammonium hexafluorophosphate(TBAPF6) as the supporting electrolyte in dichloromethane-acetonitrile (5:95, v:v). Nuclear magnetic resonance spectroscopy (1H-NMR, 13C-NMR) was utilized for the characterization of the monomer and the soluble polymer. The polymer was further characterized by Gel Permeation Chromatography (GPC). Spectroelectrochemistry and switching ability of the polymer were investigated by UV&ndash / vis spectrophotometer and cyclic voltammetry. The polymer revealed three distinctive colors upon doping which indicated that the polymer is multichromic. Tert-butyl group on the pendant phenyl rings and hexyl groups on thiophene enhanced the solution processability of the electrochromic polymer. The electrochemical and spectral properties of the chemically synthesized polymer were investigated via spray coating on ITO glass slides. Electrochemical copolymerization of 2,3-bis(4-tert-butylphenyl)-5,8-bis(4-hexylthiophen-2-yl) quinoxaline (HTQ) with 3,4-ethylenedioxythiophene(EDOT) was performed to fulfill a strategy in achieving fine-tuned electrochromic properties. The copolymer, P(HTQ-co-EDOT) was characterized via detailed studies of cyclic voltammetry and spectroelectrochemistry. Band gap (Eg) of the copolymer was calculated as 1.4 eV and showed 34 % optical contrast with switching times less than 1 second.

In the first part of this study, 4-(2,5-di-2-thiophen-2-yl-pyrrol-1-yl)-phthalonitrile (SNS-PN) was synthesized by utilizing 1,4-di(2-thienyl)-1,4- butadione (SOOS) and 4-aminophthalonitrile via Knorr-Paal Reaction. Nuclear magnetic resonance (1H NMR and 13C NMR) and fourier transform infrared (FTIR) spectroscopies were utilized for the characterization of this compound. SNS-PN monomer was then electrochemically polymerized in acetonitrile/0.2 M LiClO4 solvent/electrolyte couple. Characterizations of the resulting polymer P(SNS-PN) were carried out by cyclic voltammetry (CV), UV&ndash / vis and FTIR spectroscopic techniques. Spectroelectrochemical studies revealed that P(SNS-PN) has an electronic band gap of 2.5 eV and exhibits electrochromic behaviour. The switching ability of polymer was also monitored. It was also found that P(SNS-PN) was fluorescent and its fluorescence intensity enhanced in the presence of cations. In the second part, novel tetrakis (4-(2,5-di-2-thiophen-2-yl-pyrrol-1-yl)) substituted metal-free (H2Pc-SNS), zinc (ZnPc-SNS) and nickel phthalocyanine (NiPc-SNS) complexes were synthesized and characterized by elemental analysis, FTIR and UV-Vis spectroscopies. The solution redox properties of these complexes were also studied by using CV and differential pulse voltammetry. All of the complexes showed two reversible reduction peaks having ligand-based character and one irreversible oxidation peak. Also, the electrochemical polymerization of these complexes was performed in dichloromethane/tetrabutylammonium perchlorate solvent/electrolyte couple. Resulting polymer films were characterized by UV&ndash / vis and FTIR spectroscopic techniques and their electrochemical behaviors were investigated utilizing CV. In-situ spectroelectrochemical investigations revealed that all the polymer films could be reversibly cycled and exhibit electrochromic behavior. Furthermore, the band gap of P(H2Pc-SNS), P(ZnPc-SNS) and P(NiPc-SNS) were calculated as 2.38 eV, 2.25 eV and 2.69 eV, respectively. Moreover, the fluorescence property of the P(ZnPc-SNS) was investigated in dimethyl sulfoxide and toluene.

A new class of &amp / #960 / -conjugated monomers was synthesized with combination of electron donating and electron-withdrawing heterocyclics to understand the effects of structural differences on electrochemical and optoelectronic properties of the resulting polymers. The use of this alternating donor-acceptor-donor strategy allows the synthesis of low band gap polymers in which the redox, electronic, and optical properties are controlled through easily approachable synthetic modification of the polymer backbone. This control allows fine-tuning of the band gap to values between 1.0 and 1.8 eV by making structural changes. These structural manipulations yield varied electronic absorption energies for a range of colors in the neutral polymer films, multi-colored electrochromism, and accessible states for reduction leading to n-type doping. The polymers prepared were characterized using cyclic voltammetry, colorimetry, and UV-Vis-NIR spectroscopy demonstrating that the polymers can undergo both p- and n-type doping and color changes in both redox states.

Polycarbynes ( poly(hydridocarbyne), poly(methylcarbyne) and poly(phenylcarbyne) ) are a class of network polymers which are primarily composed of tetrahedrally hybridizated carbon atoms which have hydrogen, methyl or phenyl pendant group linked via three carbon-carbon single bonds to form a three dimensional network of fixed rings. This backbone oers unusual properties on the polymer including thermal decomposition to form diamond and diamondlike carbon. In this thesis, polycarbynes were synthesized by electrolytical reduction of trihaloorganocompounds, namely chloroform, hexachloroethane, 1,1,1-trichloroethane and 1,1,1-trichlorotoluene. Poly(hydridocarbyne) was synthesized using chloroform and hexachloroethane. Poly(methylcarbyne) was synthesized from 1,1,1-trichloroethane. Poly(phenylcarbyne) was synthesized from 1,1,1-trichlorotoluene. Polycarbynes were characterized by UV/Vis spectroscopy, 1H and 13C NMR spectroscopy, FTIR and GPC. All results are found to be consistent with literature / and thus a single step cheap, safe and easy method was introduced to scientists and manufacturers in diamond science. The resulting polymers were heated upon 1000oC under nitrogen atmosphere for 24 hours yielding in the formation of diamond and diamond-like carbon. Results indicated that both diamond films and powders were successfully produced from polycarbynes. Diamonds formed from the polymers were characterized via optical microscope, SEM, X-ray and Raman spectroscopy. All results shown in thesis are completely consistent with studies previously done for polycarbynes and diamond.

Intrinsically conducting polymers (ICPs) with high mechanical strength and electrical conductivity are attractive for several applications spanning the fields of energy, defense, and transportation. Electrochemically processed polythiophene (PTh) films are a class of ICPs that have been demonstrated recently to possess electrical conductivities as high as 1,300 S/cm and be stronger than common types of processed aluminum foils. While these results are promising, the electrical conductivity of PTh is still low compared to metals and the effects of important process conditions such as electrode resistance, distance between working and counter electrodes, and thiophene concentration on the structure and physical properties of electrochemically processed PTh films must be investigated in detail. In this work, electrode resistance and inter-electrode distance were demonstrated to be inversely proportional to the charge efficiency for PTh film growth. A critical concentration of thiophene that produced films with the highest conductivity was also revealed. Anionic surfactants sodium dodecyl sulfate (SDS) and sodium dodeclybenzene sulfonate (SDBS) were used, with and without a proton scavenger, in the Lewis acid boron trifluoride diethyl etherate (BFEE) electrolyte, which allows polymerization of thiophene at low oxidation potentials, to enhance the ordering and conjugation length of PTh through stabilization of the radical cation of thiophene via the dodecyl chain of the anionic surfactants. X-ray diffraction spectra revealed enhanced order and packing when surfactant was used during the processing of PTh films, and measured electrical conductivities were increased by as much as 300% because of the surfactant-mediated structural improvements. Necking behavior observed in tensile test of PTh films with anionic surfactant additives also suggests chain alignment and increased chain length.

Synthesis of 2-[(3-thienylcarbonyl)oxy]ethyl 3-thiophene carboxylate (TOET), 2,3-bis-[(3-thienylcarbonyl)oxy]propyl 3-thiophene carboxylate (TOPT), and 3-[(3-thienylcarbonyl)oxy]-2,2-bis{[(3-thienylcarbonyl)oxy]}propyl 3- thiophene carboxylate (TOTPT), and their copolymerization either with thiophene or pyrrole were achieved. The chemical structures of the monomers were investigated by Nuclear Magnetic Resonance Spectroscopy (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). Electrochemical behavior of the monomers and copolymers were studied by cyclic voltammetry (CV). The resultant conducting copolymers were characterized via FTIR, Thermal Gravimetry Analysis (TGA), Differential Scanning Calorimetry (DSC), and morphologies of the films were inspected by Scanning Electron Microscope (SEM). Conductivities of the samples were measured by using four-probe technique. The electrochromic and spectroelectrochemical properties of the copolymers were investigated.

Synthesis and characterization of conducting copolymers were achieved by using thiophene-3-yl acetic acid cholesteryl ester (CM) and poly (3-methylthienyl methacrylate) (PMTM). A new polythiophene containing a cholesteryl side chain in the &amp / #946 / -position was chemically polymerized in nitromethane/carbon tetrachloride using FeCl3 as the oxidizing agent. Polymerization was also achieved by constant current electrolysis in dichloromethane. Subsequently, conducting copolymers of thiophene-3-yl acetic acid cholesteryl ester (CM), PCM1 (obtained from chemical polymerization method), PCM4 (obtained from constant current electrolysis) with pyrrole were synthesized. Thiophene functionalized methacrylate monomer (MTM) was synthesized via esterification of the 3-thiophene methanol with methacryloyl chloride. The methacrylate monomer was polymerized by free radical polymerization in the presence of azobis (isobutyronitrile) (AIBN) as the initiator. Graft copolymers of poly (3-methylthienyl methacrylate)/polypyrrole, (PMTM2/PPy) and poly (3-methylthienyl methacrylate)/polythiophene, (PMTM2/PTh) were synthesized by constant potential electrolyses. PMTM2 coated Pt electrodes were utilized as the anode in the polymerization of pyrrole and thiophene. Moreover, oxidative polymerization of PMTM1 was studied by galvanostatic and chemical techniques. Characterizations of the samples were performed by CV, FTIR, NMR, DSC, TGA and SEM analyses. Electrical conductivities were measured by the four-probe technique. Immobilization of invertase in conducting copolymer matrices, poly (3-methylthienyl methacrylate) with pyrrole and thiophene was achieved by constant potential electrolysis using the sodium dodecyl sulfate as the supporting electrolyte. Polythiophene was also used for immobilization matrices. Cholesterol oxidase has been immobilized in conducting copolymer of thiophene-3-yl acetic acid cholesteryl ester with polypyrrole (CM/PPy) and polypyrrole (PPy) by the electropolymerization method. p-Toluene sulfonic acid was used as a supporting electrolyte. Kinetic parameters (Kinetic parameters / Vmax and Michaelis-Menten constant / Km) and operational stability of enzyme electrodes were investigated. Surface morphology of the films was also examined.

A new thiophene derivative containing menthyl group (MM) was synthesized and polymerized via chemical and electrochemical methods. Polymers obtained and MM itself were used to synthesize copolymers with pyrrole under conditions of constant potential electrolysis. Cyclic Voltammetry, thermal analysis and scanning electron microscopy analyses were performed for the characterization of samples. Immobilization of invertase and polyphenol oxidase enzymes was performed in the matrices obtained via copolymerization of MM with pyrrole. Immobilization was carried out via entrapment of enzyme in matrices during the polymerization of pyrrole. Temperature optimization, operational stability and shelf-life of the enzyme electrodes were investigated. Maximum reaction rate (Vmax) and Michaelis-Menten constant (Km) were determined. It is known that wine includes phenolic groups that give astringency in high concentrations. Polyphenol oxidase (PPO) converts mono and diphenols to quinone. By analyzing the product, one can find out the amount of phenolic groups. By using obtained enzyme electrodes via immobilization of PPO, amount of phenolics in different wines were analyzed.

Synthesis and characterization of thiophene ended poly-&amp / #949 / -caprolactone (PCL) and oxalic acid dithiophen-3-yl methyl ester (ODME) and their copolymers with both pyrrole and thiophene were achieved. Chemical structure of the precursor polymer and monomer were investigated Redox behavior of polymer and monomers were determined by Cyclic Voltammetry (CV). Structural characterization of samples were carried out by 1H, 13C Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). Conductivities of the films were measured by using four probe technique. Thermal analyses of conducting copolymers were investigated via Differential Scanning Calorimetry (DSC) and Thermal Gravimetry Analysis (TGA). The morphologies of the copolymer films were examined by Scanning Electron Microscopy (SEM). Electrochromic and spectroelectrochemical behavior of the copolymers were investigated, and their ability of employment in device construction has been examined.

ACTIVITY ANALYSIS OF IMMOBILIZED TYROSINASE ENZYME IN THE PRESENCE OF DIFFERENT INHIBITORS Narli, ISil M.Sc., Department of Chemistry Supervisor: Prof. Dr. Levent Toppare May 2006, 97 pages Immobilization of tyrosinase enzyme was performed in the matrices obtained via copolymerization of terephthalic acid bis-(2-thiophen-3-yl ethyl) ester (TATE) with pyrrole. During electrochemical polymerization of pyrrole, enzyme molecules were entrapped in the copolymer matrice. Activity measurements were performed by using Besthorn&amp / #8217 / s Hydrazone method which includes spectrophotometric analysis of quinones produced by the enzyme. Enzyme electrodes were characterized in terms of maximum reaction rate (Vmax) and Michaelis-Menten constant (Km). In addition to kinetic parameters, stability of enzyme electrodes towards environmental conditions such as pH and temperature was investigated. Usage stability and shelf-life analysis were also examined. Wines, especially red wines, contain numerous biologically active compounds, the most important of which are polyphenols, whose nutritional importance is attributed to their antioxidant power. The amounts of phenolic compounds in different red wines were analyzed by using obtained enzyme electrodes. The phenolic compound determination using free enzyme cannot reflect the actual values since there are also naturally found inhibitors in red wines. Benzoic acid, cinnamic acid and sorbic acid were utilized to understand the behavior of immobilized tyrosinase in the conducting polymer matrices toward inhibition.