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Poly(ethylene oxide) (PEO)-based polymer electrolytes are a promising class of materials for use in lithium-ion batteries due to their high ionic conductivity and flexibility. In this study, the effects of polymer architecture including linear, star, and hyperbranched and salt (lithiumbis(trifluoromethanesulfonyl)imide (LiTFSI)) concentration on the glass transition (Tg), microstructure, phase diagram, free volume, and bulk viscosity, all of which play a significant role in determining the ionic conductivity of the electrolyte, have been systematically studied for PEO-based polymer electrolytes. The branching of PEO widens the liquid phase toward lower salt concentrations, suggesting decreased crystallization and improved ion coordination. At high salt loadings, ion clustering is common for all electrolytes, yet the cluster size and distribution appear to be strongly architecture-dependent. Also, the ionic conductivity is maximized at a salt concentration of [Li/EO ≈ 0.085] for all architectures, and the highly branched polymers displayed as much as three times higher ionic conductivity (with respect to the linear analogue) for the same total molar mass. The architecture-dependent ionic conductivity is attributed to the enhanced free volume measured by positron annihilation lifetime spectroscopy. Interestingly, despite the strong architecture dependence of ionic conductivity, the salt addition in the highly branched architectures results in accelerated yet similar monomeric friction coefficients for these polymers, offering significant potential toward decoupling of conductivity from segmental dynamics of polymer electrolytes, leading to outstanding battery performance.

Polyaniline (PANI) is a promising conductive polymer for use in energy storage applications. Here, a one-step hydrothermal method of PANI polymerization on carbon felt electrode was synthesized using an azo dye, a bisulfonated dichloro anionic dye molecule to enhance an efficient textile-based flexible supercapacitor electrode material for energy storage applications. The electrode material synthesized at concentration of 2 mM AY17 exhibits 814.1 F g-1 at the scan rate of 5 mV s-1 with multiwall carbon nanotubes (MWCNTs). Due to electrostatic interaction with the polymer, the presence of high electronegativity Cl atoms in the dye molecule significantly improves the PANI structure's electron donor/acceptor properties. A symmetric supercapacitor exhibits an energy density of 11.7 W h kg−1 at a power density of 300 W kg−1, and it is 4.5 W h kg−1 at 1800 W kg−1 in 3.0 M KCl aqueous electrolyte. The capacitance retention performance value of the symmetric supercapacitor exhibited 81.76% after 2500 cycles.

Injecting hydrogen into the natural gas network to reduce CO2 emissions in the EU residential sector is considered a critical element of the zero CO2 emissions target for 2050. Burning natural gas and hydrogen mixtures has potential risks, the main one being the flame flashback phenomenon that could occur in home appliances using premixed laminar burners. In the present study, two-dimensional transient computations of laminar CH4- + air and CH4 + H-2 + air flames are performed with the open-source CFD code OpenFOAM. A finite rate chemistry based solver is used to compute reaction rates and the laminar reacting flow. Starting from a flame stabilized at the rim of a cylindrical tube burner, the inlet bulk velocity of the premixture is gradually reduced to observe flashback. The results of the present work concern the effects of wall temperature and hydrogen addition on the flashback propensity of laminar premixed methane-hydrogen-air flames. Complete sequences of flame dynamics with gradual increases of premixture velocity are investigated. At the flame flashback velocities, strong oscillations at the flame leading edge emerge, causing broken flame symmetry and finally flame flashback. The numerical results reveal that flashback tendency increase with increasing wall temperature and hydrogen addition rate. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Dye sensitized solar cells (DSSCs) are photovoltaic devices that produce electricity from the photon energy of sunlight using dyes. Dyes used DSSCs should have a broad absorption spectrum at the UV-Vis region and should be strongly bound to the photoanode surface. Dyes are used in DSSCs can be classified into three types: metal complex dyes, metal-free organic dyes and natural dyes. For metal complex dyes, ruthenium is usually used as metal centers. While most Ru complex dyes have high efficiency, Ru is a rare metal. To decrease the cost of Ru complex dyes, transition metals are widely investigated. In this work, diphenylcarbazone and tartrazine with different metal complexes were synthesized and investigated for their suitability for DSSCs. UV-Vis was used for the characterization of dyes and linear sweep voltammetry and electrochemical impedance spectroscopy were used to investigate the performance of DSSCs.

© 2023 Elsevier B.V.Because of the brain\"s complexity, developing effective treatments for neurological disorders is a formidable challenge. Research efforts to this end are advancing as in vitro systems have reached the point that they can imitate critical components of the brain\"s structure and function. Brain-on-a-chip (BoC) was first used for microfluidics-based systems with small synthetic tissues but has expanded recently to include in vitro simulation of the central nervous system (CNS). Defining the system\"s qualifying parameters may improve the BoC for the next generation of in vitro platforms. These parameters show how well a given platform solves the problems unique to in vitro CNS modeling (like recreating the brain\"s microenvironment and including essential parts like the blood-brain barrier (BBB)) and how much more value it offers than traditional cell culture systems. This review provides an overview of the practical concerns of creating and deploying BoC systems and elaborates on how these technologies might be used. Not only how advanced biosensing technologies could be integrated with BoC system but also how novel approaches will automate assays and improve point-of-care (PoC) diagnostics and accurate quantitative analyses are discussed. Key challenges providing opportunities for clinical translation of BoC in neurodegenerative disorders are also addressed.

PAAQ (Poly(2-amino-anthraquinone)) films were prepared through electrochemical oxidation of 2-amino-anthraquinone monomer in anhydrous acetonitrile using the supporting electrolyte tetrabutylammonium perchlorate. The effects of scan rate, cycle number, and monomer concentration on polymer film formation were investigated. Electrochemical detection of nitrobenzene (NB) on PAAQ modified glassy carbon electrode was examined with voltammetry and differential pulse voltammetry. The polymer-modified electrode exhibited excellent reducing ability towards NB compared to the unmodified electrode. The NB sensor developed on the polymer-modified electrode showed a wide linear response range of 0.0625 - 8 mM and a low detection limit of 2.294 mM., PAAQ (Poli(2-amino-antrakinon)) filmler, destekleyici elektrolit tetrabütilamonyum perklorat kullanılarak susuz asetonitril içinde 2-aminoantrakinon monomerinin elektrokimyasal oksidasyonu ile hazırlandı. Polimer film oluşumu üzerinde, tarama hızının, çevrim sayısının ve monomer konsantrasyonunun etkisi incelenmiştir. PAAQ ile modifiye edilmiş camsı karbon elektrot üzerinde, nitrobenzenin (NB) elektrokimyasal tespiti dönüşümlü voltametri ve diferansiyel puls voltametri ile incelendi. Polimer modifiye elektrot, modifiye edilmemiş elektrot ile karşılaştırıldığında NB'ye karşı mükemmel indirgeme yeteneği sergiledi. Polimer modifiye elektrotta geliştirilen NB sensörü, 0.0625 - 8 mM arasında geniş bir doğrusal cevap ve 2.294 mM düşük dedeksiyon limiti gösterdi.

The synthesis of the novel phthalonitrile containing (2,4,5-trimethylphenyl)ethynyl moieties was performed using the palladium-catalyzed Sonogashira crosslinking methodology. Cobalt phthalocyanine was obtained with the cyclotetramerization reaction of this dinitrile derivative, while the synthesis of zinc and manganese phthalocyanines was reported by the Sonogashira coupling reaction of the appropriate iodo phthalocyanines. Voltammetric and electrochromic analyses were applied to determine the possible applications of these complexes in different electrochemical/display technologies. The rich redox responses of the complexes had a good influence on the spectroelectrochemical characters of them. Electrochromic measurements of the complexes indicated fast, and reversible color changes with reasonable optical contrasts.

Cadmium zinc sulfoselenide, CdZnSSe, and reduced graphene oxide-cadmium zinc sulfoselenide (RGO)-CdZnSSe composite-based photoelectrodes are fabricated using a facile, simultaneous co-electrodeposition by repetitive cyclic voltammetric (rCV) for the first time in literature. With this method, CdZnSSe particles are homogeneously decorated among the RGO sheets by controlling the composition of the composite structure and the film thickness with rCV. Photoelectrochemical, optical, and structural properties of photoelectrodes are evaluated to investigate their usability in photoelectrochemical hydrogen evolution. Decorating Cd0.8Zn0.2S0.2Se0.8 among RGO sheets leads to a slight red-shift of the absorption edge because of the less transparency of fabricated photoelectrode which decreases the band gap of composites. Among all Cd0.8Zn0.2SxSe1-x (x = 0.0, 0.2, 0.5, 0.8, 1.0) photoelectrodes, Cd0.8Zn0.2S0.2Se0.8 demonstrates the sharp rise in photocurrent density (4.08 mA cm−2). Decorating Cd0.8Zn0.2S0.2Se0.8 with RGO at an optimum composition jumps the photocurrent density up to 5.00 mA cm−2 in addition to the improved stability. The long-term stability of RGO(0.25)-Cd0.8Zn0.2S0.2Se0.8 is reported as 89.8% at the end of the 48th hour. The applied bias photon to current efficiency (ABPE) and Faradaic efficiency are obtained as 3.07% and 89.9%. Enhanced photoelectrochemical performance indicates the superiority of the proposed rCV technique for the fabrication of well-controlled photoelectrodes consisting of RGO[sbnd]CdZnSSe composites.

We report the synthesis of non-peripheral metallophthalocyanines which carry four 4-(4-methoxyphenyl)-2-thiazole-2-thio units. H-1-NMR, FT-IR, UV-Vis, and MS data were acquired to characterize the synthesized compounds. Voltammetric and in situ spectroelectrochemical measurements shed light on the redox properties of the metallophthalocyanines (MPcs) in order to show the influence of the metal cations and thiazole-bearing substituents. In solution, the redox processes had an influence to the electrochromic responses, which were examined with in situ spectrocolorimetry. Phthalocyanines having cobalt (II), manganese (III), iron (III), and zinc (II) at the center yielded characteristic redox couples which are metal- and/or Pc-based and which are harmonious with the common redox properties of these types of compounds. In situ spectroelectrochemistry provided the information that MPc species underwent distinct color changes during electron transfer reactions. Electropolymerization of all complexes was performed on glassy carbon electrode, and the electropolymerized film of FePc was evaluated as an active electrocatalyst, in the alkaline medium, for oxygen evolution reaction (OER).

Elektrokromik camlar, bir elektrik akımı uygulandığında renk değişimi gösteren cihazlardır. Bu renk değişimi camın üzerine yapılan kaplamalar vasıtasıyla olur. Elektrokromik camların oluşturduğu sistem, literatürde akıllı cihazlar olarak adlandırılır. Akıllı cihazlar; cam, saydam iletken tabaka (ITO), katodik tabaka, iyon taşıyıcı, anodik tabaka, transparan iletken tabakadan oluşur. Anodik ve katodik tabakanın modifikasyonu, elektrokromik temelli uygulamaların önde gelen araştırma konularından biridir. Akıllı cihazlardaki renklenme için katodik tabakanın ve anodik tabakanın içerisine iyon giriş-çıkışı gerekmektedir. Bu tez çalışmasında; renklenen akıllı cihazların, katodik tabakasında kullanılmak üzere çeşitli oranlarda Zirkonyum (Zr) katkılanmış Tungsten Oksit (WO3) filmleri oluşturulup, bu filmlerin Li+ iyonu içeren bir sıvı elektrolit içerisindeki elektrokromik ölçümleri gerçekleştirilmiştir. Amaç, katodik tabakanın; renk değişiminin yüksek olması ve yaşam ömrünün literatürdeki diğer çalışmalara göre uzun olmasını sağlamaktır. Saydam iletken tabaka olarak kullanılan ITO elektrotlara, elektrokromik tabaka oluşturmak için farklı parametrelerde kaplamalar yapılmıştır. Magnetron sıçratma yöntemiyle %50 oksijen, %50 argon gazı olan ortamda 45 Watt (W) güçte Tungsten (W) metal hedefi kullanılarak katkısız WO3 filmi oluşturulmuştur. Ayrıca 45 W Tungsten metal hedefi ile aynı anda Zr metal hedefi 10 W, 20 W, 30 W, 40 W güçlerde yakılarak Zr:WO3 katkılı filmleri oluşturulmuştur. Bütün fimlerin kalınlıkları birbirine yakın olup yaklaşık 130 nm civarıdır. Örneklerin hepsi Taramalı Elektron Mikroskobu – Enerji Dağılım Spektrometresi (SEM-EDS) yöntemiyle karakterize edilmiştir. Yüzey ve tanecik özelliklerine taramalı elektron mikroskobu (SEM), atomik kuvvet mikroskobu (AFM), X ışını kırınımı (XRD) yöntemleri kullanılarak bakılmıştır. Elektrokromik özellikleri; Dönüşümlü voltametri (CV), Kronoamperometri (CA) ve eş zamanlı Ultraviyole – Görünür Işık (UV-Vis) Spektrofotometri yöntemleri kullanılarak belirlenmiştir. Elektrokimyasal karakterizasyon ve elektrokromik özelliklerin tayini için üç elektrotlu sistem kullanılmıştır. CV ve CA grafiklerine bakılarak filmlere iyon giriş-çıkış miktarları ve optik yoğunluklar hesaplanmıştır. Elektrokimyasal ölçümler, eş zamanlı spektroelektrokimyasal ölçümlerle (UV–Vis) birlikte değerlendirilmiş ve filmlerin geçirgenlik farkları kıyaslanmıştır. Her bir filmin yaşam ömrü belirlenip, hangi filmin kaç çevrime kadar kararlılığını koruduğu ve hangi katkılanma oranıyla hazırlanan filmin daha dayanıklı olduğu incelenmiştir. Bu sonuçların ışığında; %1,4 ve %2,8 Zr katkılama oranı ile oluşturulan filmlerin daha uzun ömürlü ve daha yüksek verimlilikte çalıştıkları gözlenmiştir. Metal oksit temelli ince filmlerinin elektrokromik açıdan incelenmesi hakkında pek çok araştırma gerçekleştirilmektedir. Manyetik sıçratma yöntemiyle elde edilen Zr katkılı WO3 filmlerin; elektrokromik özelliklerinin ve bu özelliklere farklı oranlarda katkılama etkisinin incelenmesi hakkında benzer bir çalışmaya literatürde rastlanmamıştır. Bu tez çalışmasından çıkacak sonuçlar, akıllı cihazlarda kullanılabilecek malzemelere farklı bir boyut kazandırabilir. Electrochromic glasses are devices that show color change when electric current is applied. This color change occurs through coatings applied to the glass. The system created by electrochromic glasses is referred to as smart devices in the literature. Smart devices consist of glass, transparent conductive layer (ITO), cathodic layer, ion conductor, anodic layer, and transparent conductive layer.Modification of the anodic and cathodic layers is one of the leading research topics in electrochromic-based applications. Ion intercalation and de-intercalation into the cathodic and anodic layers are required for coloration in smart devices.In this thesis study, various ratios of Zirconium (Zr)-doped Tungsten Oxide (WO3) films were grown for use in the cathodic layer of color-changing smart devices, and electrochromic measurements of these films were conducted in a liquid electrolyte containing Li+ ions. The aim was to ensure a high color change and long life time of the cathodic layer compared to other studies in the literature.ITO electrodes, used as transparent conductive layers, were coated with different parameters to create an electrochromic layer. Undoped WO3 films were created using a Tungsten (W) metal target with 45 Watts (W) growth power, the sputter consisting of 50% oxygen and 50% argon gases, using magnetron sputtering. In addition, Zr:WO3 doped films were created by simultaneously sputtering Zr metal targets with 45 W Tungsten metal target at growth power of 10 W, 20 W, 30 W, and 40 W. The thickness of all films was approximately 130 nm. All samples was characterized using Scanning Electron Microscope - Energy Dispersive Spectroscopy (SEM-EDS). Surface and particle properties were examined using scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD) methods. Electrochromic properties were determined using Cyclic Voltammetry (CV), Chronoamperometry (CA), and simultaneous Ultraviolet - Visible Light (UV-Vis) Spectrophotometry methods. A three-electrode system was used for electrochemical characterization and determination of electrochromic properties. The ion intercalation/de-intercalation amounts and optical densities of the films were calculated by examining CV and CA graphs. Electrochemical measurements were evaluated along with in-situ spectroelectrochemical (UV–Vis) measurements, and the transmittance differences of the films were compared. The long life time of each film was determined. The stability of each film was investigated to determine at which cycles it remained stable and which doping ratio resulted in more durability. Based on these results, it was observed that films created with Zr doping ratios of 1,4% and 2,8% exhibited longer life time and higher efficiency. Numerous studies have been conducted on the electrochromic examination of metal oxide-based thin films.A similar study investigating the electrochromic properties of Zr-doped WO3 films obtained by magnetron sputtering and the effect of different doping ratios on these properties has not been found in the literature. The results obtained from this thesis study can provide a different dimension to materials that can be used in smart devices.

© 2022 The Authors. Published by American Chemical Society.Catalysts based on metal-free conjugated porous polymers (CPPs) are still rare for electrochemical oxygen reduction reactions (ORR). In this study, a conjugated porous polymer, TT-TPB, based on thieno[3,2-b]thiophene (TT) and triphenylbenzene (TPB), was synthesized applying palladium(0) catalyzed Suzuki coupling reaction and its ORR activity was investigated in alkaline condition. It demonstrated comparable electrocatalytic performance of ≈0.89-0.9 V Eonset vs RHE with the commercially available Pt/C. Density-functional theory (DFT) calculations revealed that TT-TPB featured efficient electrocatalytic active sites derived from volumetric, areal, and O2 adsorbing calculations, which were in line with the experimental results. Moreover, semiconducting and surface properties of TT-TPB were investigated in detail using electrochemical and spectrophotometric techniques. This work shows the potential application of thienothiophene-based metal-free CPP in the electrochemical conversion process.

Traditional study has discovered that natural materials such as wood are scarce and that synthetic materials can serve as suitable substitutes. Polymer chemicals, plant materials, chemical compounds, inorganic compounds, and other corrosion inhibitors all use metals. When technology fails, corrosion is one of the most severe consequences, causing harm to the financial system, natural resources, and people's lives. Natural materials such as wood are scarce, according to traditional research, and synthetic materials may serve as suitable replacements. Polymers as corrosion inhibitors have piqued researchers' attention from both a theoretical and practical standpoint. It has been seen from the research that natural polymer inhibitors exhibits more than 90% efficiency and good surface cover on carbon steel surface. A summary of forms of corrosion, corrosion processes, and recent work on the application of polymer inhibitors on the basis of parameters such as cost, convenience of use, environmental impact, and reliability has been reviewed.

© 2022 Indian Chemical SocietyThe main aim of this study is to formulate the combination of the bioactive composite containing chitosan/β -tricalcium phosphate (CH/β-TCP) as potential drug delivery platforms for the sustained release of antibiotics. Herein the mode of amoxicillin (AMX) maintained in the β-TCP/chitosan composite was characterized using XRD, FT-IR to confirm the phase purity and functional groups. SEM was used to examine the size and shape of particles. The SEM images of the biocomposites after drug release confirmed that they are biodegradable. In vitro drug release experiments in PBS (pH 7.4) revealed a sustained release profile in a neutral medium. Drug release profiles were evaluated according to five different kinetic models including Zero Order, First Order, Higuchi, Hixon Crowel, and Korsmeyer-Peppas. The release profile was best expressed by the Korsmeyer Peppas model because the results showed high linearity. Overall, the positive effect of chitosan coating on the drug elution profile of β-TCP as carriers for the controlled delivery of antibiotics was regarded as biocompatible for the controlled drug delivery system.

Food safety is a crucial issue; all countries have struggled against pesticides for years. In this study, Polypyrrole (PPy)- and Polyacrylonitrile (PAN)-based non-enzymatic electrochemical sensors were investigated to detect the pesticide propamocarb (PM) in food samples. Under the experimental conditions, the proposed strategy exhibited a high selectivity of the disposable PPy-based and PAN-based sensors for the determination of propamocarb pesticide in the concentration of 1 μM with a rapid detection within 1 min at pH 7.4 and 25 °C. We demonstrated the detection of PM residues on cucumber and tomato samples with good electrochemical performances towards the real-time usability on real food samples. PAN-based non-enzymatic electrochemical sensor has good sensitivity, higher selectivity, and stability than PPy-based non-enzymatic electrochemical sensor. The prepared PAN-based non-enzymatic electrochemical sensor is a potential candidate to be used in devices which perform food safety in agricultural products.

Zinc–nickel alloy coating (ZnNi) was successfully deposited on carbon steel (CS) applying current density of 47 mAcm-2 with galvanostatic technique. The ZnNi alloy coating image showed that CS metal surface was plated with a blue-grey homogeneous layer. Polyaniline film (PANI) film was synthesized with cyclic voltammetry technique from 0.10 M aniline containing 0.20 M sodium oxalate solution on ZnNi coated carbon steel (CS/ZnNi) electrode surface. And then the synthesis of top PPy film was achieved in pyrrole monomer containing acetonitrile + tetrabutyl ammonium perchlorate medium successfully. After the top PPy synthesis, it was observed that both the PANi homopolymer film and the ZnNi coating continued to exist on the CS surface. The corrosion behaviors of uncoated and coated electrodes were investigated in 3.5% NaCl solution. For this aim, the anodic polarization plots and electrochemical impedance spectroscopy technique were used. The results showed that the top PPy homopolymer film provided an effective barrier property on CS/ZnNi/PANi electrode and a remarkable anodic protection to substrate for longer exposure time.

Bu çalışmada, az, orta ve koyu gibi değişik derecelerde farklı kavrulmuş kahve çekirdekleriyle demlenen Türk ve Filtre kahvelerindeki toplam antioksidan kapasitesinin (TAC) belirlenmesi için dönüşümlü (CV), kare dalga sıyırma (SWSV) ve diferansiyel puls sıyırma (DPSV) voltametrik yöntemlerle kullanıldı. Voltametrik parametreleri, karbon pasta elektrotu (CPE) kullanılarak pH 4.0 Britton-Robinson tampon çözeltisinde optimize edildi. Standart antioksidan maddeleri olarak gallik asit ve kuersetin'in elektrokimyasal davranışı CPE üzerinde optimum koşullar altında CV, SWSV ve DPSV teknikleri ile incelendi. Her üç elektrokimyasal tekniklerle (CV, SWSV, DPSV) gallik asit için yaklaşık 350 mV ve 700 mV'ta olmak üzere iki oksidasyon piki görülürken, kuersetin için ise 340 mV, 725 mV ve 1015 mV'larda anodik pikleri elde edildi. Bununla birlikte, kahve örneklerindeki toplam antioksidan kapasitelerini eşdeğer gallik asit ve kuersetin cinsinden belirlemek için CPE kullanılarak pH 4.0'da her iki maddeye ait yaklaşık 350 mV'de anodik pik akımları tercih edildi. Az kavrulmuş kahve çekirdekleriyle hazırlanan kahve örneklerinde maksimum antioksidan kapasite (TAC) gösterdiği bulundu. Az kavrulmuş kahve çekirdekleri ile hazırlanan Türk kahvesi için TAC değeri, CV yöntemi kullanılarak 17.868 ± 0.281 g/L ve 65.165 ± 1.024 g/L eşdeğer gallik asit ve kersetin olarak hesaplandı. Ayrıca, Filtre kahvesi için, TAC değerleri sırasıyla 32.290 ± 0.839 g/L ve 118.471 ± 3.529 g/L olarak bulundu. Dahası, tüm kahve örneklerindeki TAC değerleri CV'nin yanı sıra DPSV ve SWSV ile analiz edildi. Sonuç olarak, elektrokimyasal yöntemlerle, hızlı, ucuz ve ön işlemlere tabi tutulmadan doğrudan gıda örneklerinde TAC analizi edilmektedir., In this study, cyclic (CV), square wave stripping (SWSV) and differential pulse stripping voltammetric (DPSV) methods were used to determine total antioxidant capacity (TAC) in Turkish and Filter coffees brewed with differently roasted coffee beans such as light, medium and dark. Voltammetric parameters were optimized in pH 4.0 Britton-Robinson buffer solution using carbon paste electrode (CPE). Electrochemical behavior of gallic acid and quercetin as standard antioxidant substances were investigated on CPE under optimum conditions by CV, SWSV and DPSV. With all three electrochemical techniques (CV, SWSV, DPSV), two oxidation peaks were observed for gallic acid approximately at 350 mV and 700 mV, while anodic peaks were obtained for quercetin at 340 mV, 725 mV and 1015 mV. However, anodic peak currents at 350 mV for both substances were preferred using CPE to determine total antioxidant capacities in coffee samples in terms of equivalent gallic acid and quercetin. It was found that coffee samples prepared by light roasted coffee beans showed maximum antioxidant capacity (TAC). TAC values for Turkish coffee prepared with less roasted coffee beans were calculated as 17.868±0.281 g/L and 65.165±1.024 g/L equivalent gallic acid and quercetin using CV method. Also, TAC values for filter coffee were 32.290±0.839 g/L and 118.471±3.529 g/L, respectively. Moreover, TAC values in all coffee samples were also analyzed with DPSV and SWSV as well as CV. As a result, TAC analysis is carried out directly on food samples with electrochemical methods, fast, cheap and without pre-treatment.

In this study, α-Fe2O3 and tetraethyl orthosilicate (TEOS) coated Fe2O3 (TEOS@Fe2O3) was synthesized by the sol-gel method. The morphological properties and electrochemical detection of quercetin antioxidant with Fe2O3 and TEOS@Fe2O3 nanomaterials were evaluated. TEOS@Fe2O3 material was modified on a glassy carbon electrode (GCE) for the detection of quercetin with a linear range of 1.0-9.0 μM by square wave voltammetry (SWV). TEOS@Fe2O3/GCE sensor ca 1.6 and 2.5 times more sensitive than Fe2O3/GCE and GCE. The quantification (LOQ) and detection (LOD) limits were found to be 306 and 92 nM for quercetin antioxidant on the TEOS@Fe2O3 modified electrode. Quercetin was also determined in an apple tea sample with a standard addition method and the recovery of quercetin was obtained to be 104.16% and 106.04%. The results obtained from this study show that the TEOS@Fe2O3 modified electrode examined as an voltammetric sensor was found to be simple and sensitive to quercetin.

In this work, it was studied to obtain the anticorrosive properties of polymer films (SS/PABA and SS/PABA-ORG) synthesized on stainless steel surface by adding an organic substance to aniline derived o-aminobenzyl alcohol monomer synthesis medium. Firstly, polymer coating bath was prepared by dissolving 0.15 M o -aminobenzyl alcohol monomer in electrolyte solvent containing acetonitrile and 0.15 M LiClO4. From this bath, poly (o-aminobenzyl alcohol) (PABA) film was synthesized in 30 segments by a cyclic voltammetry (CV) technique at a scanning rate of 50 mV/s at a potential range of -0.20/1.80 V on the AISI 316 (SS) working electrode in contrast to the platinum electrode. For the synthesis of organic structure doped polymer film (PABA-ORG), the same synthesis process was repeated by dissolving C21H27NO2(k) (ORG) at low concentration in the same bath. Corrosion performances of bare SS, SS/PABA and SS/PABA-ORG substrates were investigated using open circuit potential – time, anodic polarization and AC impedance techniques in corrosive solution. As a result of the study, it was observed that the organic additive added to the synthesis medium caused changes in the synthesis behavior of PABA. Corrosion performance tests showed that PABA and PABA-ORG films increased the corrosion protection performance of SS electrode and it was observed to reduce the corrosion rate of SS electrode.

© 2022 Taylor & Francis Group, LLC.A simple, rapid, and precise high performance liquid chromatography (HPLC) method was developed to determine the flavonoid apigenin in cosmetic products containing chamomile extracts. A C18 column was used as stationary phase and 70:30 ethanol:water was used as mobile phase with a 1 mL/min flow rate and isocratic elution. The temperature was stabilized at 25 °C during the separation. The injection volume was 50 μL. The apigenin peak was eluted at 4.15 ± 0.4 min. The method was validated according to International Conference on Harmonisation (ICH) criteria in terms of linearity, limit of detection, limit of quantitation, selectivity, sensitivity, robustness, accuracy, and precision. The limits of detection and quantitation were 0.060 and 0.2 μg/mL respectively. The linear range was from 0.2 to 20 μg/mL. The relative standard deviation values for intraday and interday analyses were less than 1.64%. The developed procedure was applied to the analysis of various cosmetic products. It is expected that the method is suitable for routine analysis, quality control and standardization of cosmetic products for apigenin.

Bu çalışmada, üç-dişli bis-benzimidazol piridin türevi ligant (L) ve bu ligantın nötr Zn(II) kompleksi [ZnLCl2] sentezlendi. Elde edilen bu yeni koordinasyon bileşiğinin yapısı aydınlatılarak, elektrokimyasal özellikleri araştırıldı. Moleküllerin yapısal karakterizasyonunda çeşitli spektroskopik yöntemler (FT-IR, 1H NMR, 13C NMR, MALDI-TOF-MS, UV-Vis gibi) kullanıldı. Elektrokimyasal özellikleri ise DMF içerisinde dönüşümlü voltametri (CV) tekniği ve kare dalga voltametrisi kullanılarak araştırıldı. Tarama hızı ve pik akımı arasındaki ilişki kullanılarak kompleksin elektrokimyasal mekanizması aydınlatılmış, kompleksin yarı-tersinir ve difüzyon kontrollü bir davranış sergilediği ortaya konulmuştur. Bu nedenle, kompleksin özellikle de redoks akışlı piller, güneş pilleri ve elektrokataliz gibi alanlarda uygulanabileceği düşünülmektedir., In this study, tridendate bis-benzimidazole pyridine derivative ligand and its neutral Zn(II) complex [ZnLCl2] were synthesized. The structure of this novel coordination compound obtained was elucidated and its electrochemical properties were investigated. In the structural characterization of the compounds were used various spectroscopic methods (such as FT-IR, 1H-NMR, 13C-NMR, MALDI-TOF-MS, UV-Vis). Its electrochemical properties were investigated in DMF using cyclic voltammetry (CV) technique. The obtained results showed that the complex exhibits quasi-reversible redox potential. Its electrochemical properties were investigated using cyclic voltammetry (CV) technique and square wave voltammetry in DMF. Using the relationship between the scanning rate and the peak current, the electrochemical mechanism of the complex was elucidated and it was lay out shown that the complex exhibits a quasi-reversible and diffusion-controlled behavior. Therefore, it is thought that the complex can be applied especially in fields such as redox flow cells, solar cells, and electrocatalysis.

With the ever-increasing demand to textile products, the textile industries and the textile industry wastewater increases rapidly, making it one of the most important industrial source wastewater in the world. The biggest problem encountered in textile industry wastewater is that wastewater contains high amounts of dyestuff. The paints mixed with waste water without sticking to the fiber during the dyeing process create color when they are applied to the receiving environment without being purified, disrupt the aesthetic appearance and negatively affect the photosynthesis by reducing the light transmittance of the water. Therefore, the treatment of these wastewater has become even more important.In this study, the effect of support electrolytes was investigated the to the color removal of Reactive Orange 16 (RO16) dyestuffs by Ti/IrO2 mixed metalloxide coated electrodes with electrochemical oxidation method. Na2SO4, NaNO3 and NaCl as support electrolytes were evaluated amount and contents. After determining the parameters such as current density, flow rate, pH and initial pollution concentrations, the most suitable electrolyte type was determined by evaluating the presence of the supporting electrolytes in the environment.In the presence of 50 A/m2 current density, 155.84 mL/min flow rate, pH11 and 0.01 M Na2SO4 electrolyte in the electrochemical oxidation of the model working solution with the initial pollution concentration of 30 mg/L after a 90 minute treatment period, 65% color removal efficiency and 1,7454 kwh/m3 energy consumption was obtained. In the presence of 50 A/m2 current density, 155.84 mL/min flow rate, pH0 and 0.01 M NaNO3 electrolyte in the electrochemical oxidation of the model working solution with the initial pollution concentration of 30 mg/L after a 90 minute treatment period, 51% color removal efficiency and 2,0534 kwh/m3 energy consumption was obtained. In the presence of 50 A/m2 current density, 155.84 mL/min flow rate, pH0 and 0.05 M NaCl electrolyte in the electrochemical oxidation of the model working solution with the initial pollution concentration of 30 mg/L after a 20 minute treatment period, ~100% color removal efficiency and 0,6557 kwh/m3 energy consumption was obtained., Tekstil ürünlerine olan talebin her geçen gün artması ile tekstil endüstrileri ve buna paralel olarak tekstil endüstrisi atıksuları hızla artarak dünyadaki en önemli endüstriyel kaynaklı atıksulardan birini oluşturmaktadır. Tekstil endüstrisi atıksularında karşılaşılan en büyük problem atıksuların yüksek miktarlarda boyar madde içermesidir. Boyama sürecinde elyafa yapışmadan atık suya karışan boyalar arıtılmadan alıcı ortama verildiklerinde renk oluşturmakta, estetik görünümü bozmakta ve suyun ışık geçirgenliğini azaltarak fotosentezi olumsuz yönde etkilemektedir. Bu nedenle bu atıksuların arıtılmaları daha da önemli hale gelmiştir.Bu çalışmada Ti/IrO2 karışık metaloksit elektrotlarla Reaktif Orange 16 (RO16) boyarmaddesinin elektrokimyasal oksidasyon yöntemi ile renk giderimine destek elektrolit tür ve derişiminin katkısı araştırılmıştır. Destek elektrolit olarak Na2SO4, NaNO3 ve NaCl kullanılmıştır. Akım yoğunluğu, akış hızı, pH, başlangıç kirlilik derişimleri gibi parametreler belirlendikten sonra destek elektrolitlerin ortamdaki varlığı değerlendirilerek en uygun elektrolit türüne karar verilmiştir.Başlangıç kirlilik derişiminin 30 mg/L olduğu model çalışma çözeltisinin Na2SO4 elektroliti ile elektrokimyasal oksidasyonunda 50 A/m2 akım yoğunluğu, 155,84 mL/dk akış hızı, pH11 ve 0,01 M elektrolit varlığında 90 dk’lık bir arıtım süresi sonunda %65 renk giderim verimi ve 1,7454 kwh/m3 enerji tüketimi elde edilmiştir. Başlangıç kirlilik derişiminin 30 mg/L olduğu model çalışma çözeltisinin NaNO3 elektroliti ile elektrokimyasal oksidasyonunda 50 A/m2 akım yoğunluğu, 155,84 mL/dk akış hızı, pH0(5,94) ve 0,01 M elektrolit varlığında 90 dk’lık bir arıtım süresi sonunda %51 renk giderim verimi ve 2,0534 kwh/m3 enerji tüketimi elde edilmiştir. Başlangıç kirlilik derişiminin 30 mg/L olduğu model çalışma çözeltisinin NaCl elektroliti ile elektrokimyasal oksidasyonunda 50 A/m2 akım yoğunluğu, 155,84 mL/dk akış hızı, pH0(5,71) ve 0,05 M elektrolit varlığında 20 dk’lık bir arıtım süresi sonunda ~%100 renk giderim verimi ve 0,6557 kwh/m3 enerji tüketimi elde edilmiştir.

Herein, two novel ion-selective electrodes are reported for simultaneous potentiometric determination of Fe3+ and Cu2+ ions. The liquid polymeric membrane components were optimized and the resulting pencil graphite electrodes gave Nernstian slopes of 20.7 mV/decade and 31.2 mV/decade with lower detection of limit of 1×10-6 mol L-1 and 2×10-6 mol L-1, and wide pH range of 1.5-3.5 and 2.0-4.7 for Fe3+ and Cu2+ ions, respectively. The electrodes exhibited very fast response time (

The free radical scavenging properties of 1,3,4-oxadiazoles have been explored by the application of quantitative structure activity relationship (QSAR) studies. The entire data set of the oxadiazole derivatives were minimized and subsequently optimized at the density functional theory (DFT) level in combination with the Becke's three-parameter Lee-Yang-Parr hybrid functional (B3LYP) hybrid functional and 6-311G* basis set. Kennard Stone algorithm was employed in data division into training and test sets. The training set were employed in QSAR model development by genetic function algorithm (GFA), while the test set were used to validate the developed models. The applicability domain of the developed model was accessed by the leverage approach. The varation inflation factor, degree of contribution and mean effect of each descriptor were calculated. Quantum chemical and molecular descriptors were generated for each molecule in the data set. Five predictive models that met all the requirements for acceptability with good validation results were developed. The best of the five models gave the following validation results: , , and c , rmsep . The QSAR analysis revealed that the sum of e-state descriptors of strength for potential hydrogen bonds of path length 9 (SHBint9) and topological radius (topoRadius) are the most crucial descriptors that influence the free radical scavenging activities of 1,3,4-oxadiazole derivatives.

Bu çalışmada, BODIPY içeren yeni elektroaktif M1, M2, M3 ve M4 ligandlarını ve bu monomerlerden dört farklı BODIPY/ ZnO bazlı P(M1-co-EDOT)/ZnO, P(M2-co-EDOT)/ZnO, P(M3-co-EDOT)/ZnO ve P(M4-co- EDOT)/ZnO nanokompozit kopolimer malzemeleri döngüsel voltametri tekniği kullanılarak sentezlendik. Elekrokimyasal analiz sonuçları, P(M1-co-EDOT)/ZnO, P(M2-co-EDOT)/ZnO, P(M3-co-EDOT)/ZnO ve P(M4-co-EDOT)/ZnO'nun sırasıyla 1,56, 2,51, 1,18 ve 1,12 eV'da elektronik band boşluklarına sahip olduğunu göstermektedir. Sentezlenen bileşikler Raman, 1H ve 13C NMR, FT-IR ve EDX spektroskopileri ile karakterize edildi. Sentezlenen bileşiklerin optik özellikleri UV-Vis, yüzey morfolojileri SEM ve AFM kullanılarak, araştırıldı. Sentezlenen monomerlerden M1 ve M2 kopolimer nanokompozit filmlerden P(M1-co-EDOT)/ZnO ve P(M2-co-EDOT)/ZnO'nun antibakteriyel etkileri araştırılmıştır. M1, M2, P(M1-co-EDOT)/ZnO ve P(M2-co-EDOT)/ZnO inhibisyon zonları Gram negatif bakterilere karşı 26,00, 16,34, 28,8, 18,1 mm aralığında ve Gram pozitif bakterilere karşı sırasıyla 22,44, 15, 28, 24 ve 17,7 mm'dir., In this study, new electroactive ligands M1, M2, M3 and M4 containing BODIPY and four different BODIPY / ZnO-based P (M1-co-EDOT) / ZnO, P (M2-co-EDOT) / ZnO, P (M3- co-EDOT) / ZnO and P (M4-co-EDOT) / ZnO nanocomposite copolymer materials were synthesized using cyclic voltammetry technique. Electrochemical analysis results, P (M1-co-EDOT) / ZnO, P (M2-co-EDOT) / ZnO, P (M3-co-EDOT) / ZnO and P (M4-co-EDOT) / ZnO respectively It shows that it has electronic band gaps at 1.56, 2.51, 1.18 and 1.12 eV. The synthesized compounds were characterized by Raman, 1H and 13C NMR, FT-IR and EDX spectroscopy. Optical properties of synthesized compounds were investigated by using UV-Vis, surface morphologies SEM and AFM. Antibacterial effects of P (M1-co-EDOT) / ZnO and P (M2-co-EDOT) / ZnO from the synthesized monomers M1 and M2 copolymer nanocomposite films were investigated. M1, M2, P (M1-co-EDOT) / ZnO and P (M2-co-EDOT) / ZnO inhibition zones against Gram negative bacteria in the range of 26.00, 16.34, 28.8, 18.1 mm and Gram against positive bacteria 22.44, 15, 28, 24 and 17.7 mm, respectively

The electrochemical behaviors of non-peripherally tetra substituted zinc(II) and magnesium(II) phthalocyanines were studied at glassy carbon electrode in dimethylformamide using cyclic and square wave voltammetry techniques. Electrochemical mechanisms of complexes were illuminated by using the relationship between scan rate and peak current. The complexes exhibited reversible and diffusion controlled behaviors. The effect of metal center on redox properties of complexes were investigated and compared. Electrochemical results were supported with in-situ spectroelectrochemical measurements. Moreover, the color changes were recorded and observed sharp color transitions during the reduction and oxidation redox process.

Textile industry, which has an important share in industrial pollution, plays an important role economically not only in developed countries but also in developing countries. A significant part of the industry water need arises from the textile industry. However, textile wastewater contains toxic chemical compounds that are difficult to remove by traditional treatment methods. In addition, colored dyehouse wastewater prevents organic living as well as organic pollution in the receiving environment, as it prevents the transmission of sunlight. The treatment of textile wastewater and its use as process water attracts great interest both academically and industry.In this study, the contribution of NaCl support electrolyte to the color removal with the electrochemical oxidation method of Reactive Orange 16 (RO16) dyestuff by Ti/RuO2 mixed metaloxide coated electrode was investigated and toxic effects were evaluated in the analysis results. In optimization studies with NaCl support electrolyte, parameters such as current density, flow rate, pH and initial pollution concentrations were studied. The study was terminated by applying the optimum conditions obtained to different pollution concentrations, evaluating the color and toxicity.In the presence of 50 A/m2 current density, 155.84 mL/min flow rate, pH0 and 0.06 M NaCl electrolyte in the electrochemical oxidation of the model working solution with the initial pollution concentration of 30 mg/L after a 25 minute treatment period, ~100% color and 0,8008 kwh/m3 energy consumption was obtained. In the presence of 50 A/m2 current density, 155.84 mL/min flow rate, pH0 and 0.06 M NaCl electrolyte in the electrochemical oxidation of the model working solution with the initial pollution concentration of 125 mg/L after a 40 minute treatment period, ~100% color and 0,9240 kwh/m3 energy consumption was obtained. In the experimental study where the initial pollution concentration was 125 mg/L in the optimum conditions obtained, 80% toxicity removal was obtained., Endüstriyel kirlenmede önemli bir paya sahip olan tekstil endüstrisi yalnız gelişmiş ülkelerde değil gelişmekte olan ülkelerde de ekonomik açıdan önemli rol almaktadır. Sanayi su ihtiyacının önemli bir kısmı tekstil endüstrisinden kaynaklanmaktadır. Bununla birlikte tekstil atıksuları geleneksel arıtma yöntemleri ile giderimi güç zehirli kimyasal bileşikleri içermektedir. Ayrıca renkli boyahane atıksuları alıcı ortamda organik kirliliğin yanı sıra güneş ışığı geçirimini engellemesi sebebi ile canlı yaşamını da engellemektedir. Tekstil atıksularının arıtılarak proses suyu olarak kullanılması gerek akademik gerekse de sektör bazında büyük ilgi çekmektedir. Bu çalışmada Ti/RuO2 karışık metaloksit elektrot ile Reaktif Orange 16 (RO16) boyarmaddesinin elektrokimyasal oksidasyon yöntemi ile renk giderimine NaCl destek elektrolitinin katkısı araştırılmış ve analiz sonuçlarında toksik etkiler değerlendirilmiştir. NaCl destek elektroliti ile yapılan optimizasyon çalışmalarında akım yoğunluğu, akış hızı, pH, başlangıç kirlilik derişimleri gibi parametreler çalışılmıştır. Elde edilen optimum koşullar farklı kirlilik derişimlerine uygulanmış, renk ve toksisite değerlendirilerek çalışma sonlandırılmıştır.Başlangıç kirlilik derişiminin 30 mg/L olduğu model çalışma çözeltisinin NaCl elektroliti ile elektrokimyasal oksidasyonunda 50 A/m2 akım yoğunluğu, 155,84 mL/dk akış hızı, pH0 (6,12) ve 0,06 M elektrolit varlığında 25 dk’lık bir arıtım süresi sonunda ~%100 renk giderimi ve 0,8008 kwh/m3 enerji tüketimi elde edilmiştir. Başlangıç kirlilik derişiminin 125 mg/L olduğu model çalışma çözeltisinin NaCl elektroliti ile elektrokimyasal oksidasyonunda 50 A/m2 akım yoğunluğu, 155,84 mL/dk akış hızı, pH0 (6,03) ve 0,06 M elektrolit varlığında 40 dk’lık bir arıtım süresi sonunda ~%100 renk giderimi ve 0,9240 kwh/m3 enerji tüketimi elde edilmiştir. Elde edilen optimum koşullarda başlangıç kirlilik derişiminin 125 mg/L olduğu deneysel çalışmada %80 toksisite giderimi elde edilmiştir.

Küçük moleküller 1000 Da altında büyüklüğe sahip farmasötik veya doğal kökenli moleküllerdir. Küçük molekül modeli olarak bağımlılık yapıcı moleküllerin analizine yönelik elektroaktif ve optik yüzeyler oluşturmak bu tez projesinin konusunu oluşturmaktadır. Çalışmalarda analizleri yapılmak üzere kullanımları son yıllarda hızla artan bağımlılık yapıcı küçük moleküllerden kokain ve bonzai seçildi. Bu maddelerin seçimli ve duyarlı analizine imkan sağlayabilecek çeşitli fonksiyonel metalik nanoparçacıkların hazırlanması, karakterizasyonu ve uygulanma potansiyellerinin değerlendirilmesi tez projesinin temel hedefidir. Bu amaçla Fe3O4 manyetik nanoparçacıklar ile antikor temelli elektrokimyasal JWH-073 (4-bütanoik asit metaboliti) biyosensörü, kobalt nitrilotriasetik asit boncuklar ile antikor fragmenti temelli elektrokimyasal kokain biyosensörü ve altın nanoparçacıklar ile aptamer temelli kolorimetrik kokain biyosensörü geliştirildi. Bu biyosensörlerin optimizasyon ve karakterizasyon çalışmaları, sonrasında analitik performansları detaylı bir şekilde incelendi. Biyosensörler laboratuvar ortamında hazırlanan sentetik örneklerde (idrar, tükürük, ter, serum) test edildi, geri kazanımları belirlendi ve kromatografik doğrulama/kıyaslama çalışmaları gerçekleştirildi. Son olarak bazı potansiyel girişimcilerin analiz üzerine etkileri test edildi. Tez kapsamında elde edilen bulgular bütünüyle değerlendirildiğinde oluşturulan üç farklı fonksiyonel yüzey içeren test sistemlerinin başarıyla çalıştığı, sonraki bilimsel çalışmalara ve ticari ürünlere öncü nitelikte olduğu görüldü., Small molecules are pharmaceutical or natural origin molecules with a size below 1000 Da. Creating electroactive and optical surfaces for the analysis of abuse drug molecules as a small molecule model is the subject of this thesis project. To be used in the studies, cocaine and bonzai were chosen, which are abuse drug small molecules that their usage has increased rapidly in recent years. The main objective of the thesis project is the preparation, characterization and evaluation of the application potentials of various functional metallic nanoparticles that can enable selective and sensitive analysis of these substances. For this purpose, antibody-based electrochemical JWH-073 (4-butanoic acid metabolite) biosensor with Fe3O4 magnetic nanoparticles, antibody fragment based electrochemical cocaine biosensor with cobalt nitrilotriacetic acid beads and colorimetric cocaine biosensor based on gold nanoparticles were developed. Optimization and characterization studies of these biosensors and their analytical performances afterwards were examined in detail. These biosensors were tested in synthetic samples prepared in the laboratory (urine, saliva, sweat, serum), their recovery was determined and chromatographic verification / comparison studies were performed. Finally, the effects of some potential interferents on the analysis were tested. When the findings obtained within the scope of the thesis were evaluated in full, it was seen that the test systems containing three different functional surfaces were successfully working and pioneering the next scientific studies and commercial products.

Doktora tezi kapsamında karbazol türevi içeren elektroaktif gruplarla floresans özelliğe sahip azit grubu taşıyan bileşikler “klik kimyası” yöntemiyle reaksiyona sokularak 6 yeni elektroaktif monomer sentezlenmiştir. Monomerler, Nükleer Manyetik Rezonans Spektroskopisi (1H-NMR) ve Fourier Transform İnfrared Spektroskopisi (FTIR) ile yapıları aydınlatılarak floresans özellikleri Floresans Spektrofotometresi ile incelenmiştir. Sentezlenen elektroaktif monomerler dönüşümlü voltametri tekniği elektrokimyasal yolla polimerleştirilerek indiyum kalay oksit kaplı cam elektrotlarda (İTO) iletken polimer filmleri elde edilmiştir. İletken polimerlerin yüzey morfolojisi taramalı elektron mikroskobu ile incelenmiş ve spektroelektrokimyasal karakterizasyonları üç elektrotlu elektroliz hücresine bağlı UVspektrofotometre ve potansiyostat cihazının eş zamanlı çalıştırılmasıyla gerçekleştirilmiştir. Ayrıca elektrokromik özellik gösteren filmlerin akıllı camlar gibi elektrokromik uygulamalarda kullanım potansiyellerini değerlendirmek için optik kontrast, tepki zamanı ve elektrokimyasal stabilite gibi özellikleri detaylı olarak incelenmiştir. Within the scope of the doctoral thesis, 6 new electroactive monomers were synthesized by reacting electroactive groups containing carbazole derivative and compounds carrying the azide group with fluorescence property by the "click chemistry" method. The monomers were characterized by using Nuclear Magnetic Resonance Spectroscopy (1H-NMR) and Fourier Transform Infrared Spectroscopy (FTIR) spectra and their fluorescence properties were examined with Fluorescence Spectrophotometer. The synthesized electroactive monomers were polymerized by the cyclic voltammetry technique electrochemically and conducting polymer films were obtained in indium tin oxide coated glass electrodes (ITO). The surface morphology of conducting polymers was investigated by scanning electron microscopy and their spectroelectrochemical characterizations were performed by simultaneous operation of the three-electrode electrolysis cell connected UVspectrophotometer and potentiostat device. In addition, films with electrochromic properties have been examined in detail such as optical contrast, response time and electrochemical stability to evaluate their potential for using electrochromic applications such as smart glasses. Bu tez çalışması PAUBAP tarafından 2018FEBE020 nolu proje ile desteklenmiştir.

A series of symmetric bis-benzoxazole derivatives were synthesized using one-pot cyclisation reaction between 4-chloro substituted 2-aminophenol and suitable dicarboxylic acids. Synthesized compounds’ anticancer activities were tested by using MTT assay on human prostate (DU145) and breast (MCF7) cancer cells. Screening results revealed that all compounds possessed a high level anti-cancer potential by significantly decreasing the cell proliferation in prostate and breast cancer cell lines. Our compounds exerted their anti-proliferative effects in a dose and time dependent manner. Our results suggest that they can be highly potent since they were biologically active even at low concentrations. Our study presents a series of new bis-benzoxazole based compounds with potential therapeutic effects against tumor cells. Therefore, characterization of new generation bis-benzoxazole derivatives will have a significant contribution on the development of new era anti-cancer drug candidates.

The objective of this work is to prepare a new synthetic protocol of the cadmium(II) complex of bis(2,2’-methylylidenephenol)diaminoethane (H2BMPDE) and study the antimicrobial bioefficacy. In this work, we report the extractive method for the synthesis of cadmium(II) complex of bis(2,2’-methylidenephenol)diaminoethane from salicylaldehyde, ethylenediamine, hydrochloric acid, and cadmium sulfate in a single, simple step. The ligand and the complex were characterized by FTIR, UV-Vis, 1H and 13C NMR, magnetic moment, GC-MS, thermal and elemental analysis. The chemical data indicated the formation of 1:1 (metal:ligand) mole ratio and distorted tetrahedral geometry was suggested as based on spectral data and magnetic moment. The results of preliminary antibacterial study revealed that Cd(II) H2BMPDE complexes prepared from different acids (HCl, HNO3, H2SO4) were effective against clinically important Gram-negative bacteria (Escherichia coli, pseudomonas, Klebsiella ) and Gram-positive bacterium (Staphylococcus aureus).The result indicated a new synthetic protocol for the synthesis of H2BMPDE complexes. On the application, H2BMPDE and its complexes could be considered as a potential antibacterial agent with further investigative analysis.

In the present study, a simple, fast and accurate HPLC-PDA method was developed for the simultaneous determination of paracetamol (PAR), methylparaben (MP), sunset yellow (SSY) and carmoisine (CAR) in oral suspensions. The concentrations of colorants are less than with respect to those of active ingredient and this variation makes process of analysis toublesome. In the developed HPLC method, efficient chromatographic separation was achieved using reversed phase C18 column (4.6 mm x 150 mm x 5 μm particle size) and phosphate buffer solution (pH = 6.5)-acetonitrile mobile phase with a flow rate of 1.6 mL/min in the gradient mode. The eluents were monitored via a PDA detector at 300, 254 and 230 nm. The mean retention times of SSY, PAR, CAR and MP were found to be 1.58, 2.15, 3.81 and 4.42, respectively. The proposed method was validated in accordance with ICH guidelines and it was seen that the method met all requirements in terms of linearity, precision, accuracy and selectivity. The developed method was successfully applied for simultaneous determination of the studied compounds in two commercial oral suspension samples.

The preparation of new mono- and bis- NH-substituted-1,4-benzoquinones, namely 2,5-bis(5,6-dimethylbenzo[d]thiazol-2-ylamino)cyclohexa-2,5-diene-1,4-dione ( 3 ), 2,5-bis(3-(2-methylpiperidin-1-yl)propylamino)-3-chlorocyclohexa-2,5-diene-1,4-dione ( 6 ), 2-(4-tert-butylbenzylamino)-3,5,6-trichlorocyclohexa-2,5-diene-1,4-dione ( 9 ), 2-(4-fluorophenylamino)-6-tert-butylcyclohexa-2,5-diene-1,4-dione ( 12 ) is reported. The synthesis of new quinone derivatives ( 3 , 6 , 9 , 12 ) have been carried out from the reactions between quinones ( p -benzoquinone ( 1 ), 2,6-dichloro-1,4-benzoquinone ( 4 ), tetrachloro-1,4-benzoquinone ( 7 ), 2-tert-butyl-1,4-benzoquinone ( 10 )) and different amines (2-Amino-5,6-dimethylbenzothiazole ( 2 ), N-(3-aminopropyl)-2-pipecoline ( 5 ), 4-tert-butylbenzylamine ( 8 ), 4-fluoroaniline ( 11 )). The new compounds were characterized by elemental analysis, mass spectrometry, IR, 1 H-NMR, 13 C-NMR spectroscopy.

In this work, an efficient, easy, and green process has been developed for the synthesis of 2,3-dihydroquinazolin-4(1H)-one from a condensation reaction of anthranylamide with various aromatic aldehyde using of phosphate fertilizers, mono-ammonium phosphate (MAP), di-ammonium phosphate (DAP) and triple super phosphate (TSP) as heterogeneous catalysts. The reaction conditions were optimized taking into account of some parameters which control the reaction, namely the nature and the volume of the solvent and the mass of catalyst. The results show that the catalysts used herein are very interesting because they present a good catalytic activity and they are reusable for at least five cycles without any degradation of their activity .

İletkenpolimerler ilginç optik ve elektriksel özellikleri sayesinde teknolojikuygulamalarda kullanım potansiyeli en yüksek malzemelerden biridir. Fakatiletken polimerlerin zayıf çözünürlüğü, kolayca işlenememesi, mekanikdayanımının ve stabilitesinin iyi olmaması gibi nedenler pratik uygulamalardakullanımını sınırlandırmaktadır. Bu çalışmada iletken polimerler organikçözücüler (diklorometan, asetonitril, kloroform vb.) yerinepolistirensülfonikasit yardımıyla hazırlanan sulu dispersiyonunun elektrokimyasalolarak polimerleştirilmesiyle elde edilmiştir. Böylelikle suda çözünmeyen birmonomer, çevre ve insan sağlığına zararlı organik çözücüler yerine sulu ortamdapolimerleştirilmiştir. Ayrıca sulu ortamda elde edilen iletken polimerinorganik çözücü varlığında elde edilen iletken polimere göre optik veelektriksel özelliklerinin daha üstün olduğu saptanmıştır. Bu makale ile çevreve insan sağlığına zararlı organik çözücülerde sentezlenen diğer iletkenpolimerlerin de sulu ortamda sentezlenebileceği ve elde edilen polimerlerinteknolojik uygulamalarda kullanımı için çok önemli olan optik ve elektrikselözelliklerinin daha üstün olabileceği gösterilmiştir., Thanksto their interesting optical and electrical properties, conductive polymers areone of the materials to have highest potential utility in technologicalapplications. But theirs usage in practical applications are limited due topoor solubility, cannot be easily processed and lack of good mechanicalstrength and stability. In this work, synthesis of conductive polymer wasachieved in environmentally friendly aqueous dispersion of polystyrene sulfonicacid instead of harmful organic solvent (dichloromethane, acetonitrile,chloroform,). Thus, a water-insoluble monomer was polymerized in an aqueousmedium instead of organic solvents which are harmful to environment and humanhealth. Also, conductive polymer obtained in aqueous medium has superioroptical and electrical properties than the conductive polymer obtained in thepresence of organic solvents. This paper has been shown that other conductivepolymers synthesized in hazardous organic solvents can be synthesized inaqueous media with superior optic and electrical properties which is importantfor the technological application.

The origins of the Hydrophobic Effect (HE), its biological significance and its experimental basis are critically addressed in this brief review. It is argued that the mechanistic work reported on the HE in recent decades needs to be reassessed, as its conclusions are apparently debatable. Essentially, it is highly inaccurate to view the HE as a repulsive interaction, which is rather an attractive one. It appears inevitable that the HE is indeed a manifestation of the perturbation of the structure of water upon the introduction of hydrocarbon molecules into its interior. There appears to be no other satisfactory explanation for the formation of micellar aggregates and the existence of the critical micelle concentration. Also, the practical significance of the HE on the reactivity of organic compounds (e.g. cycloadditions) is severely limited by their minuscule solubility levels, itself a manifestation of the HE! Other related phenomena apparently include the formation of gels and the occurrence of certain esterification reactions in water, which are briefly reviewed from a conceptual viewpoint.

In the present work, firstly the novel mono oxime (1) and asymmetric dioxime ligand (LH 2 ) (2) derived 4′-hydroxyvalerophenone as ketone were prepared under optimum conditions. Then, the bis-dioxime-based and boronic acid-capped groups containing Fe(II) and Co(II) complexes [(L) 2 M(X) 2 (BA) 2 ] (3-6) (L= Dioxime, M = Fe(II) or Co(II), X= Cl 2 or H 2 O and BA = Butyl boronic acid (BBA) or Ferrocene boronic acid (FBA)) were synthesized in a two-necked round-bottom reaction flask by direct contact of dioxime ligand (2) , and different boronic acid with metal salts (FeCl 2 .4H 2 O or CoCl 2 ) without special requirement of any additional chemical process. The prepared ligands and its Fe(II) and Co(II) complexes were characterized by means of NMR spectra, FT-IR spectra, UV-Vis spectra, LC-MS, melting point and magnetic susceptibility measurements as well as elemental analysis. The spectroscopic results demonstrated that the proposed Fe(II) and Co(II) complexes are a six-coordinated species and octahedral geometry. The infrared spectra (FT-IR) of the Fe(II) and Co(II) complexes indicated the characteristic peak at range 1208-1217 cm -1 cm corresponding υ(B-O) stretching.

Human hepatocellular carcinoma (HepG2) cells and colorectal adenocarcinoma (DLD-1) cells were treated with the synthesized water soluble phthalocyanine derivatives to understand the effect of the compounds both on colorectal and liver cancer cells. The compounds inhibited cell proliferation and displayed cytotoxic effect on these cancer cell lines however; the effect of the compounds on healthy control fibroblast cell line was comparatively lower. The compounds can be employed for cancer treatment as anticancer agents., İnsan hepatoselüler karsinoma (HepG2) hücreleri ve kolorektal adenokarsinoma (DLD-1) hücreleri, bileşiklerin hem kolorektal hemde karaciğer kanseri hücrelerindeki etkisini anlamak için sentezlenen suda çözünür ftalosiyanin türevleriyle etkileştirildi. Bileşikler hücre proliferasyonunu inhibe etti ve bu kanser hücre dizileri üzerinde sitotoksik etki gösterdi; buna karşın bileşiklerin sağlıklı kontrol fibroblast hücre hattı üzerindeki etkisi nispeten daha düşüktü. Bu bileşikler kanser tedavisinde antikanser ajanlar olarak kullanılabilir.

A simple, efficient and green procedure has been developed for the synthesis of dihydropyrimidinones (Products of Biginelli) using phosphate fertilizers (mono-ammonium phosphate (MAP), di-ammonium phosphate (DAP) and triple super phosphate (TSP)) as catalyst. The one-step reaction involved the three compounds, which are registered aromatic aldehydes, dicarbonyl compounds and the urea/thiourea. This new method provides some advantages such as obtaining excellent yields (98%), as well as the short duration of the reaction, which may attain 2 min. These catalytic heterogeneous systems present also the advantage of being easily recycled.

YÖK ID: 656460 Bu çalışmada şeker fabrikalarında kullanılan prosesin adımlarından biri olan, şeker pancarı yıkama basamağında elde edilen yıkama suyunda bulunan ağır metallerden kurşun (Pb) miktarının belirlenmesi amacıyla yeni bir voltametrik analiz yöntemi geliştirilmiştir. Elektrokimyasal ölçümlerde üçlü elektrot sistemi kullanılmıştır. Camsı karbon elektrotun bizmut ile kaplanması sonucu çalışma elektrotu olarak bizmut elektrot üretilmiştir. Referans elektrot olarak Ag/AgCl, karşıt elektrot olarak ise platin tel kullanılmıştır. Kurşun tayini için 0,1 M KNO3 ortamında ve asetat tamponunda kare dalga anodik sıyırma voltametrisi (SWASV) ile bir analitik yöntem geliştirilmiştir. Geliştirilen bizmut elektrot SWASV için 10 nM gözlenebilme sınırı ile çalışma aralığı 100 nM – 1000 nM olarak bulunmuştur. In this project, a new voltammetric method for the lead (Pb) heavy metal in the washing water obtained from the sugar beet washing step that is one of the stages of the process using in sugar plants have been developed. The three electrode cell was used in the electrochemical experiments. The working electrode was produced by coating a commercial glassy carbon electrode with bismuth. An Ag/AgCl and a platinum wire were used as reference and auxilary electrodes, respectively. A new analytical method has been enhanced for quantitative analysis of lead in 0,1 M KNO3 in acetate buffer by using square wave anodic stripping voltammetry (SWASV). It was found that the new bizmuth electrode could work with 10 nM as the limit of quantitation and in 100 nM – 1000 nM concentration range as linear working range. İÇİNDEKİLER Sayfa ÖZET -- iv ABSTRACT -- v TEŞEKKÜR -- vi İÇİNDEKİLER -- viii ÇİZELGELER DİZİNİ -- xi ŞEKİLLER DİZİNİ -- xii SİMGELER VE KISALTMALAR -- xv 1. GİRİŞ -- 1 2. KURAMSAL TEMELLER VE KAYNAK ARAŞTIRMASI -- 4 2.1. Elektroanalitik Yöntemler -- 4 2.2. Voltametri -- 5 2.3. Voltametrinin Çalışma Prenbi -- 6 2.4. Voltametrinin Hücre Bileşenleri -- 7 2.4.1. Voltametrik kap -- 7 2.4.2. Destek elektrolit -- 8 2.4.3. Çalışma elektrodu -- 8 2.4.3.1. Cıva kökenli elektrot -- 9 2.4.3.2. Katı elektrot -- 10 2.4.3.3. Dönen elektrot -- 15 2.4.3.4. Modifiye elektrot -- 16 2.4.4. Referans elektrot -- 19 2.4.5. Yardımcı (karşıt) elektrot -- 20 viii ıx Sayfa 2.5. Voltametrik Yöntem -- 21 2.5.1. Polarografi -- 24 2.5.2. Puls voltametrisi (PV) -- 24 2.5.2.1. Normal puls voltametrisi (NPV) -- 24 2.5.2.2. Diferansiyel puls voltametrisi (DPV) -- 25 2.5.2.3. Kare dalga voltametrisi (SWV) -- 25 2.5.3. Dönüşümlü voltametrisi (CV) -- 26 2.5.4. Sıyırma voltametrisi (CV) -- 28 2.5.4.1. Anodik sıyırma voltametrisi (ASV) -- 29 2.5.4.2. Katodik sıyırma voltametrisi (KSV) -- 31 2.5.4.3. Adsortif sıyırma voltametrisi (AdSV) -- 31 2.5.4.4. Potansiyometrik sıyırma voltametrisi (PSV) -- 31 2.6. Voltametrik Validasyonda Kullanılan İstatistiksel Terimler -- 31 2.7. Voltametrik Teknikler ile İlgili Çalışmalar -- 35 3. MATERYAL VE YÖNTEM -- 38 3.1. Materyal -- 38 3.1.1. Kullanılan kimyasal malzemeler -- 38 3.1.2. Kullanılan cihazlar -- 38 3.2. Yöntem -- 39 3.2.1. Deneyde kullanılan çözeltilerin hazırlanması -- 39 3.2.2. Camsı karbon elektrodun modifiye edilmesi -- 40 3.2.2.1. Bizmut kaplı camsı karbon elektrodun 10-3 M dopamin çözeltisindeki elektrokimyasal karakterizasyonu 41 x Sayfa 3.2.2.2. Bizmut kaplı camsı karbon elektrodun 10-3 M ferrosen çözeltisindeki elektrokimyasal karakterizasyonu -- 43 4. ARAŞTIRMA SONUÇLARI VE TARTIŞMA -- 47 4.1. Araştırma Sonuçları -- 47 4.1.1. Yalın GC elektrotta kurşun (II) incelenmesi -- 47 4.1.2. Kurşunun bizmut kaplı elektrotta incelenmesi -- 49 4.1.3. Bi(III) ile kaplı elektrotta SWASV optimizasyonu -- 50 4.1.4. Kare dalga anodik sıyırma voltametrisi (SWASV) sonuçları -- 50 4.1.4.1. Biktirme süresinin optimizasyonu -- 51 4.1.4.2. Biktirme frekansının optimizasyonu -- 53 4.1.4.3. Biktirme potansiyelinin optimizasyonu -- 54 4.2. Analitik Çalışma Aralığının Belirlenmesi -- 55 4.2.1. LOD (tespit sınırı) ve LOQ (alt tayin sınır) değerlerinin hesaplanması -- 57 4.2.2. Şeker pancar yıkama suyunda bizmut modifiye elektrot ile kurşun’nun voltametrik olarak miktarının belirlenmesi ve geri kazanımı -- 57 5. SONUÇ VE ÖNERİLER -- 58 KAYNAKLAR -- 60 ÖZGEÇMİŞ -- 66

Çalışmamızın ilk bölümünde, PAMAM dendrimeri (G2-PS) modifiye perde baskılı elektrota dayalı (G2-PS/SPE) empedimetrik biyosensör ile miRNA-34a tayini yapılmıştır. Empedimetrik miRNA-34a'nın tayini ve geliştirilen biyosensörün farklı miRNA'lara karşı seçimliliği, tampon ve fötal sığır serumu (FBS) ortamlarında çalışılmıştır. Çalışmamızın ikinci bölümünde, kovalent ajanlarla aktive edilmiş kalem grafit elektrotların yüzeyine grafen oksit (GO) modifiye edilmiş; hazırlanan elektrotlar (GO-CA-PGE) ile empedimetrik miRNA-34a tayini gerçekleştirilmiştir. Geliştirilen elektrotların FBS ortamında miRNA-34a'nın tayinine uygulanabilirliği ve farklı miRNA'lara karşı seçimliliği test edilmiştir. Çalışmamızın üçüncü bölümünde, biyopolimer olan kitosan (CHIT) modifiye PGE'ler (CHIT-PGE) geliştirilmiş ve antikanser ilaç Daunorubisin (Dau) ile DNA etkileşiminin voltametrik tayini gerçekleştirilmiştir. Optimum koşullarda CHIT-PGE yüzeyinde Dau-fsDNA etkileşiminin tayini için, Dau ve guanin sinyallerindeki değişimler izlenerek etkileşim mekanizması yorumlanmıştır. Çalışmamızın son bölümünde, levan (LVN) modifiye PGE'ler (LVN-PGE) geliştirilmiş ve Dau ile DNA etkileşiminin voltametrik tayini gerçekleştirilmiştir. LVN-PGE'lerle hem fsDNA ve Dau analizleri hem de etkileşimin tayini yapılmıştır. Dau ve guanin sinyallerindeki değişimlere dayalı olarak ilaç-DNA etkileşimi değerlendirilmiştir., In the first part of our study, miRNA-34a was detected by using impedimetric biosensor based on PAMAM dendrimer (G2-PS) modified screen printed electrode (G2-PS / SPE). The determination of the impedimetric miRNA-34a and the selectivity of the developed biosensor against different miRNAs were studied in buffer and fetal bovine serum (FBS) media. In the second part of our study, graphene oxide (GO) was modified at the surface of pencil graphite electrodes activated by covalent agents; impedimetric miRNA-34a detection was performed by using the prepared electrodes (GO-CA-PGE). The applicability of the developed electrodes for the determination of miRNA-34a in FBS and its selectivity against different miRNAs was tested. In the third part of our study, chitosan (CHIT) which is a biopolymer modified PGEs (CHIT-PGE) were developed and voltammetric detection of anticancer drug Daunorubicin (Dau) and DNA interaction was performed. The interaction mechanism was interpreted by monitoring the changes in Dau and guanine signals for the detection of Dau-fsDNA interaction on CHIT-PGE surface under optimum conditions. In the last part of our study, levan (LVN) modified PGEs (LVN-PGE) were developed and voltammetric detection of Dau and DNA interaction was performed. Both fsDNA and Dau analyzes and the detection of interaction was performed by using LVN-PGEs. The drug-DNA interaction was evaluated based on the changes at Dau and guanine signals.

20. yüzyılın başlarında tesadüfen keşfedilen ftalosiyanin bileşikleri birbirlerine mezo konumlardaki azot atomlarıyla birbirlerine bağlanmış dört izoindol ünitesinden oluşan makro heterohalkalı bileşiklerdir. Bu bileşikler periyodik tablodaki hemen her metalin konumlandırılabileceği büyüklükte merkezi boşluğa sahip simetrik bir makro halka içerirler. Merkezde bulunan metal iyonu ve çevredeki sübstitüentler değiştirilerek yeni ftalosiyaninler elde edilebilmektedir. Tam sentetik özellikteki ftalosiyanin bileşikleri boyar madde ve pigment olarak kullanılırlar. Ayrıca bu bileşiklerin enerji dönüşümü, elektrofotografi, optik veri depolanması, gaz sensör, sıvı kristal, lazer teknolojisi için kızıl ötesi boyar madde, kanserin fotodinamik terapisi gibi pek çok alanda da teknolojik uygulamaları bulunmaktadır. Bu bileşikler oksijenin indigenmesinde gösterdikleri elektrokatalitik etki nedeniyle, yakıt pillerinde kullanılan ancak çok pahalı olan heterojen platin katalizörüne alternatif olabilecek özelliklere de sahiptirler.Bu tez çalışmasında, tetraklor ve tetratimol gruplarına sahip mononükleer metal ftalosiyanin bileşiklerinin Pt çalışma elektrodu üzerindeki ve dimetilsülfoksit/tetrabutil amonyumperklorat ve diklorometan/tetrabutilamonyumperklorat susuz elektrolit ortamlarındaki elektrokimyasal redoks davranışları Dönüşümlü Voltametri teknikleri kullanılarak incelenmiştir. Bu ölçümler, eş zamanlı mor ötesi-görünür bölge spektroelektrokimya ve elektrokolorimetri teknikleri ile desteklenmiştir. Voltametrik ölçümler Pc bileşiklerinin ardışık birer elektronlu yükseltgenme ve indirgenme reaksiyonları oluşturduğunu göstermiştir. Eş zamanlı spektroelektrokimyasal ölçümler voltametrik ölçümler sonucunda belirlenen indirgenme ve yükseltgenme reaksiyonlarının ftalosiyanin halkası üzerinde mi metal merkezde mi gerçekleştiğini saptamamızı sağlamıştır. Söz konusu Pc bileşiklerine ait elektrokimyasal redoks özelliklerinin merkezde bulunan metal iyonlarına bağlı olarak dikkate değer bir şekilde değişiklik gösterdiği anlaşılmıştır. Diğer taraftan, eş zamanlı spektroelektrokimyasal ve elektrokolorimetrik ölçümler ise bileşiklere ait indirgenme ve yükseltgenme reaksiyonlarının ftalosiyanin halkası üzerinde mi metal merkezde mi gerçekleştiğini ve redoks proseslerine eşlik eden renk değişimlerini saptamamızı sağlamıştır. Çalışmanın son aşamasında komplekslerin oksijen indirgenmesindeki elektrokatalitik aktiviteleri incelenmiş ve merkezde yer alan metal türünün elektrokatalitik aktiflikte de önemli rol oynadığı belirlenmiştir. Mn, Fe ve Co gibi redoks-aktif metal merkeze sahip komplekslerin elektrokatalitik aktifliklerinin, Cu redoks-inaktif metal merkeze sahip komplekslerinkinden dikkate değer ölçüde daha yüksek olduğu gözlenmiştir.--------------------Phthalocyanine compounds which were accidentally explored at the beginning of the 20th century are the macrocyclic compounds comprising four isoindole units connected to each other with the nitrogen atom in the meso position. These compounds include a symmetric ring having enough central space in which almost all metals in the periodic table can be placed. New phthalocyanines can be obtained by changing the metal ion in the center and substituents on the periphery. Fully synthetic phthalocyanine compoundsare used asdyes and pigments. Furthermore, these compounds have technological applications in the areas such as energy conversion, electrophotography, optical data storage, an infrared dye for laser technology and photodynamic therapy of cancer. Due to their electrocatalytic effect in oxygen reduction, these complexes also have potential to be used as an alternative to heterogeneous platinum catalyst which is utilized in the fuel cells, but quite expensive.In this thesis study, redox behaviors of mononuclear tetrachlorine tetrathymol phthalocyanine compounds have been investigated on the Pt working electrode in nonaqueous electrolyte environments of dimethylsulfoxide/tetrabutylammonium perchlorate and dichloromethane/tetrabutylammoniumperchlorate by using Cyclic Voltammetry and Square Wave Voltammetry techniques. These techniques were supported by in situ UV-vis spectroelectrochemistry and electrocolorimetry. The voltammetric measurements showed that the Pc compounds form a series of one-electron reduction and oxidation processes following each other. It was understood that electrochemical redox properties of the phthalocyanine complexes remarkaby change depending on the central metal. On the other hand, in situ spectroelectrochemistry and electrocolorimetry measurements allowed us to determine whether the reduction and oxidation reactions of these compounds occur on the phthalocyanine ring or in metal center and the color changes associated to the redox processes. In the last stage of the study, electrocatalytic activities of the complexes in oxygen reduction were examined and the type of the metal involved in the center of the complexes was identified to play an important role in their electrocatalytic activities. Electrocatalytic activities of the complexes with redox-active metal centers such as Mn, Fe and Co were observed to be significantly high compared to the complex with the redox-inactive Cu metal center.

Tez (Yüksek lisans) -- Giresun Üniversitesi. Kaynakça var. ıx , 72 s. ; 28 cm. Demirbaş: 0063505 …

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır. Bu çalışmada, şalkon ((E)-3-(4-hidroksifenil)-1-(tiyofen-2-il)prop-2-en-1-on) içeren periferal tetra-substitue metalli ftalosiyaninler (MPc, M = Zn, Co, Ni) boya duyarlı güneş pilleri (BDGP) için kullanılmıştır. Duyarlaştırıcı olarak kullanılan MPc'lerin elektrokimyasal, optik ve fotovoltaik özellikleri incelenmiştir. Elektrokimyasal analize göre ZnPc (4) ve NiPc (6) sadece Pc halkasına ait redoks reaksiyonları verirken, CoPc (5)'nin ise metalin 3d orbitallerinin Pc'nin HOMO ve LUMO seviyeleri arasında olması sebebiyle hem metal hem de halkadan kaynaklanan redoks reaksiyonları verdiği tespit edilmiştir. Kompleksteki redoks aktif metal iyonunun elektron transferini azaltması sebebiyle 5'ten imal edilen BDGP en düşük enerji dönüşüm verimini (% 0,51) vermiştir. Buna karşın, elektron transferini azaltmayan redoks inaktif metal iyonları içeren 4 ve 6 no'lu komplekslerden yapılmış BDGP'ler ise sırasıyla % 1,27 ve % 1,11 gibi makul düzeylerde enerji dönüşüm verimleri göstermişlerdir. Verimler arasındaki küçük de olsa görülen bu fark, 4'ün 6'ya göre daha küçük bant aralığı enerjisi ve daha yüksek molar absorpsiyon katsayısı göstermesinden kaynaklanıyor olabilir. Çünkü bu özellikler, görünür bölgede geniş absorpsiyon ve yüksek fotoakım görülmesine sebep olmaktadır. Anahtar kelimeler: Şalkon, Ftalosiyanin, Metal iyonlar, Elektrokimya, Boya duyarlı güneş pilleri. In this study, the peripherally tetra-substituted metallophthalocyanines (MPcs, M = Zn, Co, Ni) bearing the chalcone, (E)-3-(4-hydroxyphenyl)-1-(thiophen-2-yl)prop-2-en-1-one, for dye-sensitized solar cells (DSSCs) were used. Electrochemical, optical and photovoltaic properties of all the MPcs as sensitizers were examined. Electrochemical studies reveal that while the ZnPc (4) and NiPc (6) give only Pc ring-based redox reactions, the CoPc (5) shows the redox reactions based on both the central metal and the ring due to the metal 3d orbitals locate between the Pc HOMO and LUMO. The DSSC based on 5 gave the lowest power conversion efficiency (0.51%), perhaps due to the presence of a redox active central metal ion in the core of the complex, which results in a decrease electron transfer in the device. However, the DSSCs based on the redox inactive central metal ions, which cannot reduce electron transfer, showed reasonable power conversion efficiencies of 1.27% and 1.11% for 4 and 6, respectively. The slight difference between the efficiencies can be attributed to narrower band gap and higher molar extinction coefficient of 4 than 6, which ensure a broader light absorption in the visible region and higher photocurrent. Keywords: Chalcone, Phthalocyanine, Metal ions, Electrochemistry, Dye-sensitized solar cells.

Poliaminler insan ve hayvanlarda fizyolojik işlevlerin yerine getirilmesinde önemli rol alırlar. Hücresel gelişim, hücre farklılaşması, enzim faaliyetlerinin ve iyon kanallarının düzenlenmesi, DNA ve protein sentezi kontrolünde görevlidirler. Gıdalarda ise putresin iki nedenle önem arz etmektedir. Birincisi, biyojen amin miktarının kalite indikatörü olarak kabul edilir olması diğeri ise sağlığa etkili toksik etkilerinin bulunmasıdır. Bu çalışmada; TiO2, CoS,In2S3 nanopartiküllerinin değişik kombinasyonları ile modifiye edilmiş elektrotlar hazırlandı ve putresin tayininde kullanılabilirliği araştırıldı. Hazırlanan modifiye elektrotların yüzey morfolojileri ve elektrokimyasal davranışları taramalı elektron mikroskopu (SEM), dönüşümlü voltametri (CV) ve elektrokimyasal impedans spektroskopisi (EIS) yöntemleri ile incelendi. Modifiye elektrotların performans faktörleri diferansiyel puls voltametrisi (DPV) yöntemiyle belirlendi ve modifiye edilmemiş elektrodun performansı ile karşılaştırıldı. Hazırlanan TiO2-CoS modifiyeli camsı karbon eletrodun (GCE) doğrusal çalışma aralığı 0,32 µM-16,66 µM, gözlenebilme sınırı (LOD) 0,09 µM, alt tayin sınırı (LOQ) 0,27 µM, tekrarlanabilirlik ve tekrar üretilebilirlikleri sırasıyla %4,7 ve %3,3 olarak tespit edildi. Tasarlanan elektrodun gıda numunelerinde putresin analizi için kullanılabilirliği araştırıldı., Polyamines play an important role in performing physiological functions in humans and animals. They are responsible for cellular development, cell differentiation, regulation of enzyme activities and ion channels, DNA and protein synthesis control. In food, putressin is important for two reasons. The first is that the amount of biogenic amine is accepted as a quality indicator and the other is that it has toxic health effects. In this study; Modified electrodes with different combinations of TiO2, CoS, In2S3 nanoparticles were prepared and their usability in the determination of putresin was investigated. Surface morphology and electrochemical behavior of the modified electrodes were investigated by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The performance factors of the modified electrodes were determined by differential pulse voltammetry (DPV) method and compared with the performance of the unmodified electrode. The linear operating range of the TiO2-CoS / GCE (glassy carbon electrode) prepared is 0,32 µM-16,66 µM, the observability limit (LOD) is 0,09 µM and the lower detection limit (LOQ) is 0,27 µM. Reusability and reproducibility were found to be 4.7% and 3.3%, respectively. The usability of the designed electrode for putresin analysis in food samples was investigated.