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https://hdl.handle.net/20.500.12684/6773

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Exciton Migration and Surface Trapping for a Photonic Crystal Displaying Charge-Recombination Fluorescence
(Wiley-V C H Verlag Gmbh, 2016) Al-Aqar, Roza; Atahan, Alparslan; Benniston, Andrew C.; Perks, Thomas; Waddell, Paul G.; Harriman, Anthony
A compact donor-acceptor molecular dyad has been synthesized by attaching an N,N-dimethylamino fragment to a naphthalic anhydride residue. The dyad shows fluorescence from an intramolecular charge-transfer state (i.e., charge-recombination fluorescence) in solution, with the photo-physical properties being strongly dependent on the solvent polarity. Similar emission is seen for single crystals of the target compound, the molecules being aligned head-to-head, although time-resolved emission profiles display dual-exponential kinetics. A second polymorph with the head-to-tail alignment also gives rise to two lifetimes that differ somewhat from those of the first structure, which are assigned to bulk and surface-bound molecules. Growing the crystal in the presence of Rhodamine B localizes the dye around the surface. Excitation of the crystal is followed by sub-ps exciton migration along the aligned stacks, with occasional crossing to adjacent stacks and trapping at the surface. Rhodamine B present at very low levels acts as the acceptor for excitons entering the surface layer. Crystals embedded in a polyester resin form an artificial light-harvesting antenna able to sensitize an amorphous silicon solar cell.
Use of ion chromatography method on the determination of some anions in the water collected from Sakarya, Turkey
(Acg Publications, 2019) Altundağ, Hüseyin; Ağar, Şerife; Altıntığ, Esra; Ateş, Asude; Sivrikaya, Sezen
In this study simultaneous analysis of seven different anions (Fluoride, Chloride, Bromide, Nitrite, Nitrate, Phosphate, and Sulfate) in13 different water samples collected from Sakarya/Turkey and it was conducted with ion chromatography method. Analyzes were performed simultaneously using the ion chromatography method. Some validation tests and the optimum conditions for the determination of anions were studied. The analysis of anions was accomplished by the dilution of the sample injection device. Samples were used to adjust the terms of the device and the results were recorded. Ion chromatography (IC) is now considered as an excellent technique for the analysis of ions in many samples.
Synthesis, characterization and investigation of tautomeric, potentiometric and antimicrobial properties of a novel unsymmetric Schiff base and its Fe(III) and Ni(II) complexes
(Univ Mohammed Premier Oujda, 2017) Nartop, Dilek; Özdemir, Özlem; Gürkan, Perihan
A new unsymmetric Schiff base [(2OH) R-CH=N-(C6H4)-CH=N-R'(2OH) R=phenyl, R' = naphthyl] with its Fe(III) and Ni(II) complexes were synthesized by a two step method. Diimine Schiff base and its complexes were characterized by elemental analysis, mass spectra, IR, H-1/C-13-NMR spectra, TGA analysis, electronic and magnetic measurements. The phenol-imine and keto-amine tautomerism of the unsymmetric Schiff base was investigated with NMR techniques and UV-visible spectra in different solvents. Also, the protonation constants of the ligand and the stability constants of its Ni(II) and Fe(III) complexes were determined potentiometrically in 1:1(v/v) ethanol-water mixture at an ionic strength of 0.5 mol.L-1 KCl and at 25.0 +/- 0.1 degrees C. The antifungal, antimicrobial activities and the minimum inhibitory concentration (MIC) values of the compounds were evaluated against Escherichia coli (0157:H7), Micrococcus luteus (NRRLB 4975), Bacillus cereus (RSKK 863) and Candida albicans (ATCC 16231).
Synthesis, antimicrobial and antimutagenic effects of novel polymeric-Schiff bases including indol
(Elsevier Science Bv, 2019) Nartop, Dilek; Özkan, Elvan Hasanoğlu; Gündem, Mehmet; Çeker, Selçuk; Ağar, Güleray; Öğütcü, Hatice; Sarı, Nurşen
Herein, the synthesis and characterization of three new polymeric-Schiff bases including indol (L-1, L-2, L-3) were reported. The antibacterial and antifungal activity of all compounds were investigated by the well-diffusion method against some selected microorganisms as potential antimicrobial agents. In addition, the anti-genotoxic properties of these polymeric-Schiff bases were examined against sodium azide in human lymphocyte cells by micronuclei (MN) and sister chromatid exchange (SCE) tests. (C) 2019 Elsevier B.V. All rights reserved.
Synthesis, Biological Activity and Structure-Activity Relationship of Novel Diphenylurea Derivatives Containing Tetrahydroquinoline as Carbonic Anhydrase I and II Inhibitors
(Wiley-V C H Verlag Gmbh, 2018) Atahan, Alparslan; Gençer, Nahit; Bilen, Çiğdem; Yavuz, Emre; Genç, Hayriye; Sönmez, Fatih; Küçükislamoğlu, Mustafa
A series of novel tetrahydroquinoline derivatives containing urea moiety was synthesized and their invitro inhibitory effects on the human carbonic anhydrase isoenzymes (hCA-I and hCA-II) were evaluated by using the CO2 hydration method. All the synthesized compounds exhibited inhibitory activity against both hCA I and hCA II with 1-(4-fluorophenyl)-3-(4-(4-p-tolyl-5,6,7,8-tetrahydroquinolin-2-yl)phenyl)urea (7k, IC50 value of 5.28M and 5.51M, against hCA I and hCA II, respectively) as the strongest inhibitor in this study. Structure-activity relationships were also investigated. The results showed that most of synthesized compounds have a higher inhibitory activity against hCA I than hCA II. Also the substituents, containing two or more pairs of non-bonding electrons, generally increased the hCA I and II inhibitory activity. Furthermore, some electronic parameters such as the highest occupied molecular orbital and the lowest unoccupied molecular orbital (HOMO-LUMO) energy levels, electron affinity, total energy and dipole moments of the best inhibitors (7b, 7h and 7k) in this study were also calculated by using Gaussian software. The results revealed that HOMO-LUMO energy differences, total energy, chemical hardness and dipole moment of 7b, 7h and 7k showed a linear relationship with increasing inhibitory activity.
Pulse Radiolysis of TIPS-Pentacene and a Fluorene-bridged Bis(pentacene): Evidence for Intramolecular Singlet-Exciton Fission
(Amer Chemical Soc, 2018) Karlsson, Joshua K. G.; Atahan, Alparslan; Harriman, Anthony; Tojo, Sachiko; Fujitsuka, Mamoru; Majima, Tetsuro
Exposing TIPS-pentacene in deaerated benzene to ionizing radiation generates a mixture of singlet- and triplet-excited states of the solute. The singlet undergoes radiative decay without spin conversion whereas the triplet undergoes radiationless decay on the microsecond time scale. The concentration of each species was established by dosimetry. The excited-singlet state is not observed on the nanosecond-time scale for a related fluorene-bridged bis(pentacene), but the triplet is present in high concentration. Failure to detect the excited-singlet state is attributed to fast intramolecular singlet-exciton fission (iSEF) which is found to produce two triplet species. A short-lived intermediate (tau(T) = 145 ns) is identified as the species (T_T) having both pentacene units present as triplet states. The second transient is longer lived (tau(T) = 7.5 mu s) and is assigned to the corresponding species (T_G) with a single pentacene promoted to the triplet level. Dosimetry is used to conclude that iSEF partitions overwhelmingly in favor of T_G (70%) relative to T_T (25%). The total triplet yield from iSEF, therefore, is ca. 120% in this system, where the pentacene terminals are weakly coupled.
Online Solid-Phase Extraction of Cd(II), Cu(II), and Co(II) Using Covalently Attached Bis(salicylaldimine) to Silica Gel for Determination in Food and Water by Flame Atomic Absorption Spectrometry
(Taylor & Francis Inc, 2018) Sivrikaya, Sezen; İmamoğlu, Mustafa
In this study, a novel sorbent material bearing a bis(aldimine) group was designed and successfully synthesized by covalently bonding a 2-[N,N-bis(salicylaldimine)]aminoethyl amine ligand to the silica gel surface that was characterized by carbon, hydrogen, and nitrogen elemental analysis, thermogravimetric analysis, and the Fourier transform infrared spectroscopy technique. The sorbent was used for the online solid-phase extraction (SPE) of Cd(II), Cu(II), and Co(II) ions for their determination at trace concentration levels by flame atomic absorption spectrometry. The effective factors for the online SPE such as the pH and the flow rate of the sample solution, and type, volume, and flow rate of eluent were investigated. The concentration levels of Cd(II), Cu(II), and Co(II) were measured in certified reference materials including Virginia tobacco leaves (CTA-VTL-2) and water-trace elements (NWTM-15.2) to validate this method. The metal levels in environmental water were determined by this method, and the values were checked by spiking and recovery experiments and independent analysis by inductively coupled plasma-mass spectrometry. The adsorption capacities of the sorbent were found to be 41.2, 31.6, and 25.6mg/g for Cd(II), Cu(II), and Co(II), respectively. This method was also successfully used for the determination of Cd(II), Cu(II), and Co(II) concentrations in rice and molasses.
On-line Preconcentration of Pd(II) Using Polyamine Silica Gel Filled Mini Column for Flame Atomic Absorption Spectrometric Determination
(Springer International Publishing Ag, 2017) Sivrikaya, Sezen; Karslı, Bülent; İmamoğlu, Mustafa
In this study, a novel method for determination of Pd(II) ions at trace level was developed using on-line preconcentration onto polyamine group bonded silica (PA-SG) with flame atomic absorption spectrometric determination. Pd(II) uptake dynamics of PA-SG was studied batchwise by investigating acidity and chloride concentration of aqueous phase, contact time and initial concentration of Pd(II) ions. The Pd(II) adsorption capacity of PA-SG was found to be 158.7 mg g(-1) from aqueous phase containing 0.1 M HCl. The on-line preconcentration procedure of Pd(II) was optimized with main analytical parameters including sample and eluent flow rate, eluent type and volume and matrix ions. The optimum eluent type and flow rate of sample and eluent were found to be 1.0% thiourea in 1.0 mol L-1 HCl and 7.5 mL min(-1), respectively. The preconcentration factor and sampling frequency were calculated to be 23.9 and 20 h(-1), respectively. The calibration graph was linear over the range 10-200 mu g L-1. The limits of detection (3 sigma) and quantification (10 sigma) values were computed to be 3 mu g L-1 and 10 mu g L-1, respectively. The RSD, % was found to be 4.6% for five measurement of 25 mu g L-1 of Pd(II) ions. The accuracy of the developed method was successfully checked by determination of Pd(II) level of certified reference material platinum ore (SARM 7B). The proposed method was successfully applied for Pd(II) determination in various environmental water samples such as river, lake, sea and tap water, and spent auto catalyst.
Novel Functionalized Silica Gel for On-line Preconcentration of Cadmium(II), Copper(II), and Cobalt(II) with Determination by Flame Atomic Absorption Spectrometry
(Taylor & Francis Inc, 2016) Sivrikaya, Sezen; İmamoğlu, Mustafa; Yıldız, Salih Zeki; Kara, Derya
Silica gel functionalized with 2-[N,N'-bis(2,3-dihydroxybenzaldimin)] aminoethylamine was employed as a novel sorbent for preconcentration of copper(II), cobalt(II), and cadmium(II) by flow injection-solid phase extraction. The pH of the analyte solution, sample and eluent flow rate, eluent volume, and the presence of concomitant ions were optimized. The limits of detection were 0.65, 0.52, and 1.42 mu g/L and preconcentration factors were 12.3, 21.5, and 7.31 for cadmium(II), copper(II), and cobalt(II), respectively. The adsorption capacities of the functionalized silica gel for cadmium(II), copper(II), and cobalt(II) ions were 41.1, 31.7, and 26.5mg/g. The preconcentration method was validated by determination of cadmium(II), copper(II), and cobalt(II) levels in Virginia Tobacco Leaves (CTA-VTL-2) and Water-Trace Elements (NWTM-15.2) certified reference materials. The method was also used to analyze water and food samples, and offers simplicity, reproducibility, high recovery, rapid and automated analysis, favorable ease of use, and low detection limits.
Anti-genotoxic Effects of Schiff bases and their Mn(III) Complexes Containing L-Aspartic acid and L-Phenylalanine
(Gazi Univ, 2018) Özkan, Elvan Hasanoğlu; Kızıl, Hamit Emre; Şakıyan, İffet; Nartop, Dilek; Sarı, Nurşen; Ağar, Güleray
The purpose of the research was to evaluate the genotoxic and anti-genotoxic properties of Schiff bases and their Mn (III) complexes containing L-aspartic acid, and L-phenylalanine. The anti-genotoxic properties of four compounds in human lymphocytes cells were investigated by sister chromatid exchanges (SCEs) test system against aflatoxin Bi (AFBi). The results showed that compounds have strong anti-genotoxic properties.
A novel vortex-assisted liquid phase microextraction method for parabens in cosmetic oil products using deep eutectic solvent
(Taylor & Francis Ltd, 2019) Sivrikaya, Sezen
The parabens, which are harmful to our bodies, are primarily utilized as preservatives in medicine, personal care products and cosmetics. A novel, more efficient, fast and cheap vortex-assisted liquid phase microextraction method based on deep eutectic solvents (DESs) was developed for the determination of parabens. The microextraction conditions were optimized using these solvents and the analytical parameters of the method were determined under optimal microextraction conditions. After extraction, the chromatographic separation of parabens was undertaken using high-performance liquid chromatography-UV detection. Experimental parameters, such as DES type, DES volume, dilution solvent volume and vortex extraction time were optimized. DES6 [ChCl-Ethylene glycol (1/2)] was the most suitable DES to work in this study. Detection limits for this method of 0.053 mu g mL(-1) for methylparaben, 0.061 mu g mL(-1) for ethylparaben, 0.049 mu g mL(-1) for propylparaben and 0.052 mu g mL(-1) for butylparaben were obtained. Correlation coefficients (R-2) for a concentration range of 0.1-100 mu g mL(-1) were higher than 0.9992 and relative standard deviation (RSD) values below 2.91% at parabens concentration of 2.5 mu g mL(-1) were obtained. The results of spike/recovery values of real samples were greater than 84%. When compared with other methods, the main advantages include lower LOD, short extraction time, rapidity, repeatability and simplicity.
One-pot PolimerleşmeYöntemiyle Poli(linoleik asit)-g-Poli(Nisopropilakrilamit)-g-Poli(D,L-laktid) Graft Kopolimerlerin Sentezi ve Karakterizasyonu
(2018) Allı, Sema; Geçit, Pınar; Gürel, Murat; Allı, Abdulkadir
Bu çalışmada, Otookside polimerik linoleik asit peroksit (PLina)’nın halka açılma polimerizasyonu ve serbestradikal polimerizasyonu bir arada kullanılarak tek adımda (one-pot) üç bloklu graft kopolimerler sentezlendi.Poli(linoleik asit)-g-poli(N-isopropilakrilamit)-g-poli(D,L-laktid) yapısına sahip graft kopolimerler; PLina’nınana zincirinde bulunan peroksit grupları ile N-isopropilakrilamit (NIPAM) monomeriyle serbest radikalpolimerizasyonu ve PLina’nın karboksilik asit grupları ile D,L-laktid (LA) monomeri arasındaki halka açılmapolimerizasyonunun bir arada (one-pot) kullanılmasıyla sentezlendiler. One-pot polimerizasyon reaksiyonunaetki eden polimerizasyon süresi, başlatıcı konsantrasyonu ve monomer konsantrasyonu gibi temel parametrelerincelendi. Elde edilen graft kopolimerlerin karakterizasyonları 1H NMR ve GPC teknikleri kullanılarak yapıldı
Halka Açılma Polimerizasyonuyla Poli(linoleik asit)-g-Poli(?kaprolakton) ve Poli(linolenik asit)-g-Poli(?-kaprolakton) Graft Kopolimerlerin Sentezi ve Karakterizasyonu
(2018) Allı, Sema; Geçit, Pınar; Gürel, Murat; Allı, Abdulkadir
Bu çalışmada, linoleik asit (Lina) ve linolenik asit (Linl)’ler otooksidasyona uğratılarak polimerik linoleik asitperoksit (PLina) ve polimerik linolenik asit peroksit (PLinl) elde edildi. Lina ve Linl’lerin otooksidasyonu havaortamında oda sıcaklığında gerçekleştirilerek % 1.10-1.20 peroksit içeren, % 98 çözünür kısımlarına sahipyapıları elde edildi. Biyobozunur poli(linoleik asit)-g-poli(?-kaprolakton) ve poli(linolenik asit)-g-poli(?kaprolakton) graft kopolimerler, otookside olmuş linoleik asit ve linolenik asit’lerin karboksilik asit grupları ile?-kaprolakton monomeri arasındaki halka açılma polimerizasyonuyla elde edildiler. Poli(linoleik asit)-g-poli(?kaprolakton) ve poli(linolenik asit)-g-poli(?-kaprolakton) graft kopolimerlerin instristik viskozite değerleribelirlendi. Elde edilen graft kopolimerlerin karakterizasyonları 1H NMR, FT-IR, TGA, DSC ve GPC tekniklerikullanılarak yapıldı
Synthesis of Nano Poly(2-thiophenecarboxaldehyde) and Characterization of Structure
(2018) Sivrikaya, Sezen; Dalmaz, Aslıhan; Durmuş, Sefa
This article describes a chemical oxidative polymerization for the preparation of nano polymeric thiopheneby using FeCl3 as oxidant. 2-thiophenecarboxaldehyde (2-THCA) compound was used as a monomer atthis polymerization process. The structure of synthesized nano polymeric thiophene was confirmed byscanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), thermogravimetricanalysis (TGA), raman spectroscopy, and elemental analysis of C, H, O and S. SEM images showed thatthe poly(2-thiophenecarboxaldehyde) (PTHCA) was synthesized in nanoscale and had a homogeneous andsmooth structure. The size of the synthesized nano particles was not more than 35 nm. Thermal analysis ofnano polymeric thiophene showed that the polymer is thermally stable up to 450-460 oC. When elementalanalysis results of PTHCA were examined, it was seen that the obtained data after the synthesis of nanopolymeric thiophene and the theoretically determined data were agree with each other.
Novel polymeric microspheres: Synthesis, enzyme immobilization, antimutagenic activity, and antimicrobial evaluation against pathogenic microorganisms
(John Wiley and Sons Inc., 2020) Nartop, Dilek; Demirel, Birtane; Güleç, Murat; Özkan, Elvan Hasanoğlu; Yetim, Nurdan Kurnaz; Sarı, Nurşen; Ağar, Güleray
New polymeric microspheres containing azomethine (1a-1c and 2a-2c) were synthesized by condensation to compare the enzymatic properties of the enzyme glucose oxidase (GOx) and to investigate antimutagenic and antimicrobial activities. The polymeric microspheres were characterized by elemental analysis, infrared spectra (FT-IR), proton nuclear magnetic resonance spectra, thermal gravimetric analysis, and scanning electron microscopy analysis. The catalytic activity of the glucose oxidase enzyme follows Michaelis-Menten kinetics. Influence of temperature, reusability, and storage capacity of the free and immobilized glucose oxidase enzyme were investigated. It is determined that immobilized enzymes exhibit good storage stability and reusability. After immobilization of GOx in polymeric supports, the thermal stability of the enzyme increased and the maximum reaction rate (Vmax) decreased. The activity of the immobilized enzymes was preserved even after 5 months. The antibacterial and antifungal activity of the polymeric microspheres were evaluated by well-diffusion method against some selected pathogenic microorganisms. The antimutagenic properties of all compounds were also examined against sodium azide in human lymphocyte cells by micronuclei and sister chromatid exchange tests. © 2019 Wiley Periodicals, Inc.

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