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Öğe 2,4-Diamino-6-Hydroxypyrimidine Based Poly(azomethine-Urethane): Synthesis and Application as a Fluorescent Probe for Detection of Cu2+ in Aqueous Solution(Springer/Plenum Publishers, 2015) Kamacı, Musa; Kaya, İsmetA novel poly(azomethine-urethane)-based 2,4-diamino-6-hydroxyprimidine was synthesized with chemical reaction and it designed as fluorescence probe for determination of Cu2+ in aqueous solution. The photoluminescence (PL) characteristic of the prepared Schiff base (HPAMP) and its poly(azomethine-urethane) (P-HPAMP) derivative were investigated in different polarity solvents suh as MeOH, THF and DMF. PL measurements showed that both HPAMP and P-HPAMP have higher emission intensity and Stoke's shift value (Delta lambda(ST)) in THF than the other solvents. Also, the proposed probe exhibited a specific fluorescent on response to Cu2+ over the other tested transition metal ions in aqueous solution. The sensor gave highly selective and sensetive response against Cu2+ as increasing a new emission peak at 341 nm, and possible interference and quenching effect of the other tested transition metal ions were found too low. Detection limit of Cu2+ sensor was also calculated as 7.87 x 10(-6) mol L-1 in THF/deionized water (1:2, v:v).Öğe 3,4-dichlorobenzyl methacrylate and ethyl methacrylate system: monomer reactivity ratios and determination of thermodynamic properties at infinite dilution by using inverse gas chromatography(Elsevier Sci Ltd, 2001) Demirelli, K.; Kaya, İsmet; Coşkun, M.Copolymers with various contents of 3,4-dichlorobenzyl methacrylate (BzMA) and ethyl methacrylate (EMA) were prepared in 1,4-dioxane solution using 2,2 ' -azobisisobutyronitrile (AIBN) as initiator at 60 degreesC. The copolymer compositions were determined by H-1 NMR analysis. The monomer reactivity ratios were calculated by both Fineman-Ross, and Kelen-Tudos methods. The monomer reactivity ratios were found to be r(BMA) = 0.521 +/- 0.019, r(EMA) = 0.847 +/- 0.221 (Kelen-Tudos) and r(BMA) = 0.677 +/- 0.008 r(EMA) = 1.117 +/- 0.209 (Fineman-Ross). The FT-IR, C-13 NMR spectra of the copolymers have been discussed. In all other samples thermal degradation proceeded in a single step. A slight increase in thermal stability of the copolymers was observed with increase in BzMA content. Some thermodynamic quantities such as the specific retention volumes, V-g(0), weight fraction activity coefficients of solute probes at infinite dilution, Ohm (infinity)(1), Flory-Huggins intereaction parameters, chi (infinity)(12), between polymers and solvents, the partial molar free energy, DeltaG(1)(infinity) the partial molar heat of mixing, DeltaH(1)(infinity), at infinite dilution were determined from the interactions of poly(BzMA-co-EMA) with alcohols, ketones, acetates, aromatics and n-alkanes by inverse gas chromatography method at 130-150 degreesC. All probes are non-solvent for poly(BzMA-co-EMA) (7:93%) and poly(BzMA-co-EMA) (87:13%) at 130-150 degreesC. (C) 2001 Elsevier Science Ltd. All rights reserved.Öğe 3-Aminopropyltriethoxysilane-mediated (phenoxy-imine) polymers: synthesis and characterization(Springer, 2019) Kaya, İsmet; Boz, Mihriban Esma; Kolcu, Feyza3-Aminopropyltriethoxysilane (3-APTES)-functionalized phenoxy-imine polymers exhibiting enhanced thermal properties have been synthesized by oxidative polycondensation using 4-hydroxybenzaldehyde, 2-hydroxy-3-methoxybenzaldehyde, 2-hydroxy-1-naphthaldehyde, 2-hydroxybenzaldehyde and 3,4-dihydroxy benzaldehyde; subsequently, the polymerized aldehydes polymers were grafted by integrating 3-APTES to form poly(imine)s. All compounds characterized by FT-IR, UV-Vis, H-1-NMR and XPS analyses revealed the existence of Si-O-C bonds in the silanized compounds. Thermal behavior (TG-DTA-DSC) of the synthesized polymers has been determined using thermogravimetric and differential scanning calorimetry techniques. The thermal stability of the phenoxy-imine polymers was enhanced significantly by incorporation of 3-APTES into the polymer backbone. Size exclusion chromatography provided information about the number average molecular weight (M-n), weight average molecular weight (M-w) and polydispersity index values of phenoxy-imine polymers. Photoluminescence and morphologic properties of the polymers at different amplifications were analyzed. The results of optical, thermal and electrical conductivity measurements indicated that the phenoxy-imine polymers were crucial due to their high electrical conductivity and heat retardancy as well as the lowest band gap for P3 derived from 2-hydroxy-1-naphthaldehyde and 3-APTES. Graphical abstract3-Aminopropyltriethoxysilane-functionalized phenoxy-imine polymers were synthesized using the polymerized aldehydes. The results of optical, thermal and electrical conductivity measurements indicated that the phenoxy-imine polymers were crucial due to their highest electrical conductivity and heat retardancy as well as the lowest band gap for P3 derived from 2-hydroxy-1-naphthaldehyde and 3-aminopropyltriethoxysilane. [GRAPHICS] .Öğe 6-Hydroxyquinoline Oligomers Emit White Light(Amer Scientific Publishers, 2014) Doğan, Fatih; Bilici, Ali; Yıldırım, Mehmet; Kaya, İsmetThe 6-hyroxyquinoline (HQ) was shown to undergo an oxidative oligomerization reaction in the alkaline medium. The obtained oligo (6-hyroxyquinoline) (OHQ) was characterized with respect to chemical composition, molecular weight, particle size, thermal stability, morphology and conductivity. FT-IR and H-1-NMR spectral data suggested that the resulting product was mainly C2, C4 and C6-coupled via C-C/C-O-C linkages. OHQ emitted white light upon irradiated at 339 nm. Optical band gap (E-g) of OHQ was determined to be 2.78 eV. The isolated product was amorphous and soluble in common polar organic solvents. The solid state conductivity studies for OHQ were also performed and found to be in the region of semiconductor.Öğe A comparative study of 9,9-bis(4-aminophenyl)fluorene polymers prepared by catalytic and non-catalytic oxidative polymerisation methods(Pergamon-Elsevier Science Ltd, 2011) Bilici, Ali; Kaya, İsmet; Yıldırım, Mehmet9.9-Bis(4-aminophenyl)fluorene (APF) polymers were synthesized by two different pathways. The different synthetic routes gave polymers with different structures. FT-IR and NMR studies revealed that the catalytic oxidative polymerisation of APF in acetonitrile produced P2, whereas oxidative polymerisation of APF in aqueous alkaline media gave P3. The effects of these different techniques on spectral, thermal, optical, electrical, electrochemical, and morphological properties of resulting polymers were investigated. (C) 2011 Elsevier Ltd. All rights reserved.Öğe A comparative study of aminothiazole-based polymers synthesized by chemical oxidative polymerization(Elsevier Science Sa, 2012) Yıldırım, Mehmet; Kaya, İsmetPoly(2-aminothiazole) derivatives were synthesized by chemical oxidative polymerization method using 2-aminothiazole (2AT), 2-aminobenzothiazole (2ABT) and 6-ethoxy-2-aminobenzothiazole (EtO-2ABT) as the monomers. Structural characterizations were carried out by Fourier Transform Infrared (FT-IR), nuclear magnetic resonance (NMR), size exclusion chromatography (SEC), and scanning electron microscopy (SEM) techniques. The synthesized polymers were investigated by the means of solubility tests, UV-vis, spectrofluorometry, cyclic voltammetry (CV), thermogravimetry-differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), and dynamical mechanical analysis (DMA) techniques. Solid state electrical conductivities were also measured on the polymer films. Phenyl attached aminothiazole polymers had higher solubilities than the unsubstituted poly(2-aminothiazole). The polymers had lower band gaps than the corresponding monomers indicating their polyconjugated structures. P-2AT and P-2ABT emitted bluish light under UV irradiation while P-EtO-2ABT emitted red color with lower intensity. Phenyl attachment and ethoxy substitution of the monomer caused production of polymer with higher thermal stability. Additionally, a discussion of electrical conductivities and morphological variations was reported. (C) 2012 Elsevier B.V. All rights reserved.Öğe A comprehensive investigation of PtNPs/PEI N-GQDs nanocomposite: DFT modeling, anticancer activity, and biosensing applications(Springer, 2025) Altınok Güneş, Buket; Kırlangıç, Ömer Faruk; Kılıç, Murat; Ketenoğlu, Didem; Aslan, Ayşenur; Kabaş, Sultan Yağmur; Kabaş, Afşar; Kaya, İsmet; Yıldız, MustafaThis research focuses on the synthesis and characterization of a novel nanocomposite, PtNPs/PEI N-GQDs, utilizing FTIR, UV-Vis, SEM, TEM, XPS, and XRD techniques. The study investigates the cytotoxic, apoptotic, and antiangiogenic effects of the nanocomposite on OVCAR-3 cells, aiming to understand the interplay between nanomaterials and cancer. Additionally, the electrochemical properties of PtNPs/PEI N-GQDs-modified glassy carbon electrodes (GCE) are explored, emphasizing analyses of HOMO-LUMO energy levels and band gap energy. Density Functional Theory (DFT) analysis results further support these findings by providing insights into the electronic structure and energetics of the nanocomposite. The nanocomposite exhibits promising electrochemical behavior, demonstrating high capacitance and sensitivity in glucose detection through cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. Selectivity towards glucose among interfering bioanalytes is highlighted, showcasing potential applications in tumor monitoring and diagnosis. Furthermore, the nanocomposite displays significant toxicity against cancer cells, inducing apoptosis and cell cycle arrest. Antiangiogenic effects are also observed, suggesting potential therapeutic benefits. Overall, these findings underscore the multifunctional properties of the synthesized nanocomposite, offering insights into its potential for cancer therapy and biosensor applications for glucose detection in bodily fluids.Öğe A cross-linker containing aldehyde functionalized ionic liquid for chitosan(Taylor & Francis Inc, 2019) Yaşar, Alper Ömer; Kaya, İsmetThe synthesis of conductive and eco-friendly new chitosan composite biopolymer with a novel aldehyde functionalized ionic liquids (AFILs) was investigated in this work. The AFILs, 1,1 '-(pentane-1,5-diyl) bis(4-formylpyridin-1-ium) dibromide (C5PyBr), 1,1 '-(octane-1,8-diyl) bis(4-formylpyridin-1-ium) dibromide (C8PyBr) and 1,1 '-(decane-1,10-diyl) bis(4-formylpyridin-1-ium) dibromide (C10PyBr) have been synthesized and they were characterized by FT-IR, UV-vis and H-1-NMR and (13) C-NMR, TG, and DSC analyses. The synthesized AFILs, C5PyBr C8PyBr and C10PyBr were used as cross-linker for chitosan biopolymers and the cross-linked chitosan composites, chitosan/1,1 '-(pentane-1,5-diyl)bis(4-formylpyridin-1-ium)dibromide (Ch/C5PyBr), chitosan/1,1 '-(octane-1,8-diyl)bis(4-formylpyridin-1-ium)dibromide (Ch/C8PyBr) and chitosan/1,1 '-(decane-1,10-diyl)bis(4-formylpyridin-1-ium)dibromide (Ch/C10PyBr) were prepared. Herein, the synthesized AFILs have not only cross-linked chitosan, but also provide them the desired novel, functional groups. The prepared chitosan composites were characterized by FT-IR for the analysis of structural, TG and DSC for the thermal behavior, and an electrometer for the electrical conductivity. The electrical conductivity of the prepared Ch/C5PyBr composite was measured as 1.69 x 10(-5) +/- 2.37 x 10(-5) S cm(-1) by the four-point probe at room temperature and this value is higher about 4500-fold than the electrical conductivity of the chitosan.Öğe A green light emitting polymer in a PMMA matrix: oligo(azomethine-ether) with benzothiazole moieties(Tubitak Scientific & Technological Research Council Turkey, 2015) Yıldırım, Mehmet; Kaya, İsmetThis study aimed to synthesize an oligo(azomethine-ether) with benzothiazole moiety in organic medium by means of chemical oxidative polycondensation (OP). Optical properties were examined by photoluminescence (PL) and UV-Vis measurements both in solutions and solid film involved a poly (methyl methacrylate) (PMMA) matrix. Oligomer film in the PMMA matrix emitted a fine green light with a fluorescence quantum yield (QY) of 3.30%. Spectral and thermal observations showed a high rate of C-O-C coupling (cross-linking) for the oligomer. SEC results indicated low molecular weight (similar to 3200-4650 g mol(-1)) and the oligomer was soluble in organic solvents with high polarity. Electrochemical behavior was characterized by cyclic voltammetry (CV), morphological properties by scanning electron microscopy (SEM), and thermal characteristics by TG-DTA and DSC techniques.Öğe A highly selective, sensitive and stable fluorescent chemosensor based on Schiff base and poly(azomethine-urethane) for Fe3+ ions(Elsevier Science Inc, 2017) Kamacı, Musa; Kaya, İsmetIn this paper, Schiff base (PAH) and its poly(azomethine-urethane) derivative (P-PAH) were synthesized and high-quality film sensor of these compounds could be easily fabricated on transparent polyester surface through dip-coating technique. Then, these films were used as fluorescence probes for the detection of metal ions in aqueous solutions. Photophysical properties of fluorescent films were investigated using fluorescence and UV-vis spectrometers. Fluorescence properties of probes were investigated in the presence of a series of different metal ions and the results showed that monomer and polymer films have a highly sensitive and selective response to Fe3+ ion in deionized water. Moreover, fluorescence measurements showed that the prepared fluorescent films have in the range 143-180 nm Stokes shift value. Also, contact angles of film probes were investigated and contact angles of PAH and P-PAH probes measured as 85 +/- 1 and 95 +/- 2 degrees, respectively. (C) 2016 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.Öğe A Kinetic Evaluation for PANSA Doped Low Density Polyethylene Blends(2019) Doğan, Fatih; Bilici, Ali; Kaya, İsmet; Şirin, MehtapIn our previous study, we prepared blends of lowdensity polyethylene (LDPE) with semiconductorpolymer, poly (1-amino-2-hydroxynaphthalene-4-sulfonic acid) (PANSA), in different mixing ratios. Inthat study, the findings on some physical and chemical properties of the blends prepared were alsopresented. In this study, it was aimed to investigate the thermal decomposition kinetics of these preparedblends. For this purpose, thermograms of PANSA doped LDPE blends at four different heating rates wereobtained. With the addition of PANSA into LDPE, it was observed that the initial decompositiontemperature and maximum decomposition temperature of LDPE increased. Thermal decompositionkinetics of blends were performed using the integral isoconversional methods (Kissinger, Kim-Park (KP),Tang, Kissenger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO)) in addition to differentialisoconversional method (Friedman method). The activation energy values calculated by Kissinger, KP,Tang, KAS, FWO and Friedman methods and found to be 187.9, 200.2, 171.90, 171.78, 171.70 and171.89 kJ mol-1for 0.5 % PANSA doped LDPE, 193.9, 206.2, 173.31, 172.87, 172.98 and 172.78 kJmol-1for 1 % PANSA doped LDPE and 207.0, 219.2, 196.94, 197.09, 198.08 and 208.10 kJ mol-1for 0.5% PANSA doped LDPE, respectively. Thermal decomposition mechanism for blends was proposed withthe help of master plot curves.Öğe A new approach for synthesis of electroactive phenol based polymer: 4-(2,5-Di(thiophen-2-yl)-1H-pyrrol-1-yl)phenol and its oxidative polymer(Elsevier Science Sa, 2012) Kaya, İsmet; Aydın, AyselIn this study, the 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)phenol (4-DTPP) was synthesized by the reaction of 1,4-di(2-thienyl)-1,4-butanedione and 4-aminophenol. This monomer was electrochemically polymerized in the presence of LiClO4 as the supporting electrolyte in acetonitrile (AN). The copolymerization were achieved in the presence of thiophene (Th) with 3,4-ethylenedioxythiophene (EDOT) in 0.1 M LiClO4/AN electrolyte-solvent couple. The polymer of 4-(2.5-di(thiophen-2-yl)-1H-pyrrol-1-yl)phenol was synthesized by oxidative polycondensation reaction in an aqueous alkaline medium using NaOCl (30%) as oxidant. The structures of compounds were confirmed by FT-IR, UV-vis, and H-1-NMR techniques. The characterizations of compounds were made by TG-DTA, DSC, gel permeation chromatography (GPC) and solubility tests. Electrical conductivities of the synthesized monomer and polymer were measured by four-point probe technique using a Keithley 2400 electrometer. Fluorescence measurements were carried out in various solvents. (C) 2011 Elsevier B.V. All rights reserved.Öğe A new approach to the Schiff base-substituted oligophenols: The electrochromic application of 2-[3-thienylmethylene]aminophenol based co-polythiophenes(Elsevier, 2011) Kaya, İsmet; Yıldırım, Mehmet; Aydın, AyselTwo new copolymers were synthesized by electrochemical polymerization of 2-[3-thienylmethylene]aminophenol (2,3-TMAP) and poly-2-[3-thienylmethylene]aminophenol (P-2,3-TMAP) with thiophene (Th) and the obtained thiophene copolymers were examined as electrochromic materials. Electro copolymerization reactions of the compounds were performed in acetonitrile (AN)/boron trifluoride ethyl etherate (BF3EtE) solvent mixture (9:1, v/v) where LiClO4 utilized as the supporting electrolyte. After electro copolymerization reaction, obtained electrochromic films deposited on ITO glass plates, 2,3-TMAP-co-Th and P-2,3-TMAP-co-Th, were investigated as spectroelectrochemically. The new electrochromic materials derived from Schiff base substituted-phenol/oligophenols are red colored at low potentials and blue colored at high potentials. Electro copolymerization mechanism was identified. Spectroelectrochemical monitoring showed good absorption recovery for P-2,3-TMAP-co-Th, while absorbance decrease was observed for 2,3-TMAP-co-Th during the repeated potential scans. Suitable potential range for operating the device from red to blue was found to be between 0 and +1.4 V. P-2,3-TMAP-co-Th showed 12-13% transmittance changes at applied potentials and the response times were 3.1 and 4.1 s for 476 and 800 nm, respectively. As a result P-2,3-TMAP-co-Th may be good candidate for electrochromic devices and can be thought as a feasible nominee for anodically coloring electrochromic layers in ECDs. (C) 2010 Elsevier B.V. All rights reserved.Öğe A new conducting polymer of 2,5-bis(2-thienyl)-1H-(pyrrole) (SNS) containing carbazole subunit: Electrochemical, optical and electrochromic properties(Elsevier Science Sa, 2009) Koyuncu, Sermet; Zafer, Ceylan; Sefer, Emre; Baycan Koyuncu, Fatma; Demiç, Şerafettin; Kaya, İsmet; Özdemir, EyüpWe report here the synthesis of a new electroactive monomer 3,6-di-tert-butyl-[4-(2,5-di-2-thienyl-1H-pyrrol-1-yl)phenyl]-9H-carbazole in five steps and polymerization of this monomer by two different procceses: Kumada Coupling and electro-oxidative. The product obtained by chemical polymerization exhibits a high thermal stability and narrow molecular weight distribution. While, in the UV-vis absorption spectrum of monomer the absorption peaks appear at 338 nm, the chemically synthesized polymer absorbs at 428 nm with 90 nm red shift. Cyclic voltammogram of monomer shows two separate oxidation processes which reflect the first oxidation at +0.84 V and a second one at +1.43 V. When the polymeric film prepared by electrochemical process was subjected to a repeated cyclic scan between -0.2V and +1.0V, it switches among three different colors (orange, green and blue). The oxidation and reduction response times were calculated as 2.0 s for this polymer film and exhibits high redox stability. The results anticipate that this kind of polymers can be used for designing electrochromics based on the use of one molecule for the generation of three basic colors (RGB). (C) 2009 Elsevier B.V. All rights reserved.Öğe A new kind of optical Mn(II) sensor with high selectivity: Melamine based poly(azomethine-urethane)(Elsevier Science Sa, 2011) Kaya, İsmet; Yıldırım, Mehmet; Kamacı, MusaIn this study a kind of poly(azomethine-urethane);toluene-2,4-diisocyanate-co-N,N',N '',-tris[(2-hydroxynaphtyl)-1-methylene]-1,3,5-triazine-2,4,6-triamine (TDI-co-2-HNMTT) was prepared as in the literature and employed as a new fluorescent probe for the detection of Mn(II) concentration. The photoluminescence (PL) measurements were carried out in the presence of several kinds of heavy metals. TDI-co-2-HNMTT gave a linearly and highly selective response against Mn(II) as growing a new emission peak at 394 nm. Possible interferences of other ions were found too low. Detection limit of the sensor was found as 1.51 x 10(-5) mol L(-1). Resultantly, TDI-co-2-HNMTT could be effectively used as an optical Mn(II) sensor. (C) 2011 Elsevier B.V. All rights reserved.Öğe A New Schiff Base Epoxy Oligomer Resin: Synthesis, Characterization, and Thermal Decomposition Kinetics(Wiley, 2011) Kaya, İsmet; Doğan, Fatih; Gül, MuratOligo{2,20-{1,4-phenylenebis[nitrilomethylylidene]} bis(6-methoxyphenol)} (OPNMMP) was synthesized from o-vanillin and p-phenylene diamine by oxidative polycondensation with NaOCl in an aqueous alkaline. Then, a new Schiff Base epoxy oligomer resin, OPNMMP-epichlorohydrine (EPC), was produced with EPC. The structures of the resulting compounds were confirmed by Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, H-1-NMR, and C-13-NMR. Further characterization processes were preformed by thermogravimetry (TG)-differential thermal analysis, gel permeation chromatography, and solubility testing. Also, the kinetics of the thermal decomposition of OPNMMP-EPC were investigated by thermogravimetric analysis. The TG curves showed that the thermal decomposition of OPNMMP-EPC occurred in one stage. The kinetic parameters related to the decomposition kinetics of OPNMMP-EPC were obtained from TG curves with the following methods: Friedman, Flynn-Wall-Ozawa, Kissinger, invariant kinetic parameter, and Coats-Redfern (CR), under an N-2 dynamic atmosphere and different heating rates (5, 10, 15, and 20 degrees C/min). The mechanism function and pre-exponential factor were also determined by a master plots method. The apparent activation energies of the thermal decomposition were calculated from these methods for OPNMMP-EPC. The analysis of the results obtained by the CR and master plots methods showed that the decomposition mechanism of OPNMMP-EPC in N-2 was a deceleration-type mechanism. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 3211-3222, 2011Öğe A new selective fluorescent sensor for Zn(II) ions based on poly(azomethine-urethane)(Pergamon-Elsevier Science Ltd, 2015) Avcı, Ali; Kaya, İsmetA new and selective fluorescent sensor based on poly(azomethine-urethane) (PAMU) is synthesized and characterized by FT-IR, H-1 NMR, and size exclusion chromatography (SEC) techniques. The new sensor shows a high selectivity for Zn(II) over other metal cations in DMF/deionized H2O (1:2, v/v). The fluorescence sensor gives a linearly and highly stable response to Zn(II) as an increasing emission peak at 595 nm. The sensitivity limit of the new sensor is found to be 11.4 x 10(-3) mol L-1. The results show that the proposed sensor can be efficiently used as a simple method for the detection of Zn(II) ions. (C) 2015 Elsevier Ltd. All rights reserved.Öğe A Novel Sensitive and Selective Amperometric Detection Platform for the Vanillin Content in Real Samples(Wiley, 2021) Karakaya, Serkan; Kaya, İsmetAccurate and sensitive determination of vanillin in commercial samples is significant for food safety & quality. In the proposed study, copper particles were coated on an indium tin oxide electrode (ITO) by cyclic voltammetry (CV) for the determination of vanillin in food samples. CV studies indicated that the electrodeposition of Cu particles provides a good electrocatalytic effect towards the oxidation of vanillin. The fabricated sensor determines vanillin linearly between 0.50 μM–2.0 mM (Limit of detection: 0.15 μM). The Cu/ITO was successfully tested on vanillin samples and the recommended method provides accurate and selective determination of vanillin in daily samples.Öğe A novel shape-controlled synthesis of bifunctional organic polymeric nanoparticles(Elsevier Sci Ltd, 2015) Doğan, Fatih; Temizkan, Kevser; Kaya, İsmetA novel shape-controlled bifunctional organic nanoparticle was reported using the facile synthesis of self-stabilized monohydroxy amino naphthol nanoparticles. For this purpose, bifunctional monomer was polymerized by NaOCl as oxidant in aqueous alkaline medium at 70 degrees C. These poly-nanoparticles with molecular weight ca. 5000 Da was obtained by template-free oxidative polymerization (OP) process. The structure of polymer was confirmed by NMR, FT-IR, UV-Vis and X-RD measurements. The chemical and physical properties of polymer were determined size exclusion chromatography (SEC), thermogravimetry (TG), differential scanning calorimetry (DSC), cyclic voltammetry (CV), photoluminescence (PL), dynamic light scattering (DLS), scanning electron microscope (SEM), transmission electron microscope (TEM) and conductivity techniques. The SEM analysis of polymer indicated to be had a nanoparticle structure. The reversible redox behavior of the polymer was attributed to its electroactive nature. In addition, the kinetic parameters related to the solid state decomposition of the poly-nanoparticles were calculated by non-isothermal methods based on multiple heating rates. (C) 2015 Elsevier Ltd. All rights reserved.Öğe A Schiff base based on triphenylamine and thiophene moieties as a fluorescent sensor for Cr (III) ions: Synthesis, characterization and fluorescent applications(Elsevier Science Sa, 2020) Kolcu, Feyza; Erdener, Diğdem; Kaya, İsmetA Schiff base fluorescent sensor was designed for selective detection of Cr3+ ions in aqueous solution. The procedure for the study was fulfilled in three steps which comprised the synthesis of 4-nitro-triphenylamine (TPA-NO2), 4-amino-triphenylamine (TPA-NH2) and Schiff base (TPA-Th) using 2,2′-bithiophene-5-carboxaldehyde, respectively. Structural characterization of the purely synthesized compounds was acquired by using UV–Vis, FT-IR, 1H NMR and 13C NMR analyses. Their electrochemical, thermal, and the optical sensor properties for metal ions were enlightened by cyclic voltammetry (CV), thermal-TG-DTA and photoluminescence (PL) techniques, respectively. Non-fluorescent TPA-Th displayed a fluorescence enhancement after chelation with Cr3+ ions with high selectivity and overall emission change of 59-fold at an excitation wavelength of 320 nm. The limit of detection (LOD) value was as low as 1.5 × 10−6 M for Cr3+ ions, accompanied by an association constant (Ka) of 2.8 × 104 M−1. TPA-Th was beneficial for the design and development of metal-complexed fluorescent sensor and light emitting devices.
