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Öğe 1-Amino-2-hydroxy-4-naphthalenesulfonic acid based Schiff bases or naphtho[1,2-d]oxazoles: Selective synthesis and photophysical properties(Pergamon-Elsevier Science Ltd, 2015) Atahan, Alparslan; Durmuş, SefaA series of Schiff base and naphtho[1,2-d]oxazole derivatives were selectively synthesized via condensation reaction of 1-amino-2-hydroxy-4-naphthalenesulfonic acid and benzaldehyde derivatives at same conditions. The synthesized compounds were then characterized by using (HNMR)-H-1,(CNMR)-C-13, FTIR spectroscopies and elemental analyses. It was seen that the Schiff bases generated in the presence of OH group at ortho position of benzaldehyde derivatives. However, the products were naphtho[1,2-d]oxazoles in other cases. Then, the synthesized compounds were photophysically investigated by UV absorption and fluorescence emission spectroscopies. As a result, these Schiff bases have shown long wavelength absorption (lambda(max): 386 nm) and emission (lambda(max): 429-437 nm) effect while synthesized naphtho[1,2-d]oxazole derivatives have a set of absorption (lambda(max): about 296, 308, 320 nm) and emission maxima (lambda(max): 378-395 nm) at lower wavelength. (C) 2015 Elsevier B.V. All rights reserved.Öğe Agaricus bisporus Ekstraktı Kullanılarak ZnO Nanopartiküllerinin Yeşil Sentezi: Yapısal Karakterizasyonu ve Biyolojik Aktivitelerinin İncelenmesi(Düzce Üniversitesi, 2023) Bekem, Ravza; Durmuş, Sefa; Dalmaz, Aslıhan; Dulger, GorkemNanoteknolojinin ilginç yönlerini keşfetmek adına son yıllarda birbirinden farklı birçok çalışma yapılmaktadır. Nanomalzeme üretiminin hızlı gelişimi, çok çeşitli alanlarda metal oksit (ZnO) uygulamalarını da beraberinde getirmiştir. Çinko oksit nanopartikülleri (ZnO NP), ticari kullanım için mekanik veya kimyasal olarak elde edilebilir. Ancak, bu tekniklerin ortaya çıkardığı çevre sorunları bir hayli dikkat çekmiştir. Günümüzde, ZnO NP’nin yeşil sentezi, çevre sorunlarını azaltmayı amaçlayan araştırma alanında özellikle ilgi görmektedir. Bu yeşil yaklaşımda, bitki özü, mikroorganizma, mantar ve alg gibi doğal bazlı malzemeler, biyoaktif fitokimyasallardaki zenginleşmeleri nedeniyle biyo-indirgeyici ve biyo-stabilizatör olarak kullanılmaktadır. Bu çalışmada, ZnO NP farklı çinko tuzları ile doğal bir ürün olan mantar ekstraktı (Agaricus bisporus) kullanılarak sentezlenmiştir. Elde edilen ZnO NP X-ışını kırınımı (XRD), Fourier dönüşümü kızılötesi spektroskopisi (FT-IR), Taramalı elektron mikroskobu (SEM) analizi, Enerji dağılımlı X-ışını analizi (EDX) ile karakterize edildi. Son olarak ZnO NP’nin bakteri ve funguslara karşı antimikrobiyal aktiviteleri kuyu difüzyon yöntemi ile ölçülerek sonuçlar kaydedildi.Öğe Biosynthesis and characterization of ?-FeOOH nanoparticles using Isabella grape (Vitis Labrusca L.) extract(2023) Ozcan, Hüseyin; Dalmaz, Aslıhan; Ozdincer, Mesut; Zenkin, Kübra; Durmuş, SefaThe advancement of environmentally sustainable and eco-friendly approaches to nanoparticle synthesis has gained significant importance in analytical chemistry. This research examined the green synthesis of iron oxyhydroxide nanoparticles, utilizing Vitis labrusca L. extract as both a reducing and stabilizing agent. The application of this natural extract offers an environmentally friendly alternative to conventional chemical synthesis techniques and is expected to meet the growing demand for sustainable applications. The synthesized iron oxyhydroxide nanoparticles were characterized using advanced techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FT-IR), to verify their composition and structure. The findings reveal the successful synthesis of iron oxyhydroxide nanoparticles with a uniform size distribution and excellent stability.Öğe Crystal Structure and Thermal Decomposition of Square Planar Ni (II) Complexes with ONS Type Ligands (vol 40, pg 788, 2010)(Springer/Plenum Publishers, 2011) Durmuş, Sefa; Arıcı, Cengiz; Şahin, Ertan; Ergün, Ümit; Atakol, Orhan…Öğe Green synthesis and structural characterization of ZnO nanoparticle and ZnO@TiO2 nanocomposite by Cinnamomum verum bark extract(2023) Keleşoğlu, Gökçenur Selva; Özdinçer, Mesut; Dalmaz, Aslıhan; Zenkin, Kübra; Durmuş, SefaIn this work, we present a facile and efficient approach for the green synthesis of ZnO@TiO2 bimetallic oxide nanoparticles by exploiting the potential of Cinnamomum verum bark extract as a biogenic reducing agent. The synthesized nanoparticles were subjected to a comprehensive characterization process comprising various spectroscopic techniques. These techniques include X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. Based on the results obtained, it highlights the potential of green-synthesized ZnO@TiO2 nanocomposite as a promising material for analytical applications.Öğe Influence of micro crystalline cellulose on EPDM-based automotive sealing profile(Sage Publications Ltd, 2023) Poyraz, Bayram; Güner, Yusuf; Yardım, Tayfun; Yamanoğlu, Rıdvan; Tozluoğlu, Ayhan; Durmuş, Sefa; Şen, MuratThis study examined the effects of microcrystalline cellulose (MCC) used in EPDM elastomer composites in replace of EPDM. For that purpose, the MCC was added in amounts of 1.75; 3, 5, and 5 , 25 phr to investigate the chemical, thermal, rheological, mechanical, morphological, and dielectric properties of EPDM elastomers. At the end of the study, the MCC enabled increased tensile strength, and elongation while causing lower thermal stability and Mooney scorch. The MCC also facilitated the vulcanization process by providing faster production while mixing homogeneously in the matrix. In addition, it decreased dielectric lossyness as well as increased the electric charge storage capacity. However, E-Cel2, containing 3, 5 phr MCC, was found to be more suitable for high-K applications, whereas E-Cel3 was more suitable for low-loss applications. In conclusion, MCC can be also recommended to automotive industries to provide more biocompatible and enhanced properties as a substitute for EPDM.Öğe Magnetic Spinel-Type CoFe2O4 Nanoparticles: Synthesis and Investigation of Structural, Morphological Properties(2017) Özdinçer, Mesut; Durmuş, Sefa; Dalmaz, AslıhanSpinel-type metal oxide nanoparticles were synthesized via co-precipitation approach. Mono ethylene glycol (MEG) was used as a capping agent to stabilize the particles and prevent them from agglomeration. The structural, morphological and thermal properties of the calcined sample were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), raman spectroscopy and thermal analysis. Energy-dispersive X-ray analysis (EDX) has also proved that the element composition was composed of pure single phase and contained Co, Fe and O elements. The mean crystallite size of the prepared ferrite nanoparticles was determined to be in the range of 30-345 nm based on the SEM images. The magnetic measurements of the CoFe2O4 nanoparticles were examined with a vibrating sample magnetometer (VSM) at room temperature to determine their magnetic behavior and the magnetic parameters were found.Öğe Preparation of Cerium Oxide Nanoparticles: An Efficient Catalyst to the Synthesis of Dimeric Disulphide Schiff Bases(2017) Durmuş, Sefa; Dalmaz, Aslıhan; Özdinçer, Mesut; Sivrikaya, SezenDimeric disulphide Schiff bases were synthesized via reactions of 2,2’-diaminodiphenyl disulphide with various aromatic aldehydes under reflux and prepared nano?sized cerium oxide as catalyst. It was observed that, when nanocatalyst was used, the catalyst could be reduced the reaction time and increased yields compared with the none-catalyst conditions. Moreover, the CeO2 nanocatalyst was easy preparation, non-hazardous, ecofriendliness and low cost. The morphological features of CeO2 nanocatalyst were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX). The structures of ligands were illuminated some techniques such as fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR) spectroscopy and thermogravimetric analysis (TGA) / differential thermal analysis (DTA)Öğe A study on the investigation of gamma shielding properties of some metal borides(Elsevier Ltd, 2019) Gülbiçim, Hasan; Türkan, M. Nureddin; Aksu, Mecit; Durmuş, SefaIn this study, the gamma radiation absorption capabilities of some metal borides were studied by using Monte Carlo simulation method. So, the mass attenuation coefficients, ? m , the half value layer, HVL, the tenth value layer, TVL and the mean free path, MFP values of the NdB 6 , SmB 6 and GdB 6 were calculated by means of EGSnrc particle transport code and XCOM program theoretically within the energy range 0.125–5 MeV. It was seen that there is a quite successful consistency (t = 0.00049, p = 0.99961) between the simulated results and calculated values obtained by NIST's XCOM photon cross-section database. Those computational results for the synthesized compounds have also been compared with lead and vermiculite which have concluded that NdB 6 , SmB 6 , and GdB 6 are good candidates for gamma shielding applications. These materials were sythesized by magnesiothermic reduction in open air. Stoichiometric amounts of M 2 O 3 , B 2 O 3 and Mg (20% excess) were mixed, where M III is a lanthanide metal (Nd III , Sm III and Gd III ) ion. Mixture was heated to 700 °C, 800 °C and 900 °C. Optimum reaction temperature and reaction time were found by X-Ray Diffraction (XRD) analysis and Scannning Electron Microscopy (SEM). By fixing the reaction temperature, reaction time has changed as 1, 2, 3, 4 and 5 h to obtain nano crystals with homogeneous morphology. It was found that optimum reaction temperature and reaction time of NdB 6 is 700 °C and 3 h, for SmB 6 700 °C and 1 h for GdB 6 900 °C. © 2019Öğe Synthesis and Characterization of Dimeric Thio-Schiff Bases by Nano Cerium Oxide and Examination of Their Antimicrobial Activities(2021) Dalmaz, Aslıhan; Durmuş, Sefa; Dülger, Görkem; Dülger, BaşaranIn this work, firstly, CeO2 nanoparticles, which can be used as catalysts in many reactions, weresynthesized by preparing aqueous solution of cerium(III) nitrate hexahydrate in basic medium.In the second step, the synthesis of dimeric thio Schiff bases was carried out using two differentmethods. Effect of catalyst on some parameters such as reaction time and yield of product wereinvestigated. The antimicrobial activities of the ligands have been screened in vitro against theorganisms Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae (Gram negativebacteria), Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Bacilluscereus (Gram positive bacteria) and Candida albicans, C. tropicalis, C. guilliermondii, C.glabrata by Disc Diffusion and Microdilution methods. At the same time, antimicrobialactivities of ligands were compared to standard antibiotics (Cefotaxime, Amoxicillin/clavulanicacid, Posacanazole, Nystatin and Gentamicin). Generally, the results obtained in this researchshowed that all tested ligands exhibited more effect towards Gram positive bacteria andCandida species as compared to standard antibiotics.Öğe Synthesis and Characterization of Disulfide-Schiff Base Derivatives and in vitro Investigation of Their Antibacterial Activity Against Multidrug-Resistant Acinetobacter baumannii Isolates: A New Study(Maik Nauka/Interperiodica/Springer, 2018) Durmuş, Sefa; Dalmaz, Aslıhan; Çalışkan, E.; Dülger, GörkemIn this study two different methods without a catalyst and with a CeO2 nano catalyst were used for the synthesis of dimeric disulfide-Schiff bases. The dimeric disulfide-Schiff base derivatives were characterized by FT-IR, NMR, and MS spectra, and elemental analysis. The disulfide-Schiff bases and their derivatives 2-5c were screened for in vitro antibacterial activity against 40 multidrug-resistant strains of Acinetobacter baumannii, and their minimum inhibitory concentrations were determined. Most of products exhibited high antibacterial activity against Acinetobacter baumannii.Öğe Synthesis and DFT study of Cd(II) and Hg(II) complexes of ONNO-type Schiff bases(Taylor & Francis Inc, 2017) Aksu, Mecit; Çifci, Mehmet; Böyükata, Mustafa; Durmuş, Sefa; Babgi, BandarThis study consists of the synthesis of cadmium (II) and mercury (II) metal complexes of ONNO-type Schiff bases. Two different ONNO-type Schiff bases were prepared. One cadmium(II) and one mercury(II) complex of the considered Schiff bases were achieved. Both are proved to be mononuclear complexes. Ligands and complexes were analyzed via melting point determination, elemental analyses, thermogravimetric (TG) analysis, infrared (IR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. Moreover, structural and energetic analyses for both complexes have been realized using Hartree-Fock (HF) and density functional theory (DFT) methods with CEP-121G basis set.Öğe Synthesis of disulphide-Schiff base derivatives and investigations of in vitro antimicrobial activities against some human pathogens(Sciendo, 2017) Durmuş, Sefa; Dalmaz, Aslıhan; Dülger, Görkem; Kadıoğlu, Duygu BircanThio-Schiff bases are becoming increasingly widespread in various branches such as the preparation of certain medicines, cosmetic products, and polymer production. In particular, the presence of antibacterial, antifungal, antiviral, antitumor and antimalarial properties of Schiff bases containing sulfur in the structure has made these compounds attractive in different disciplines. In this study, different derivatives of dimeric disulfide-Schiff bases have been synthesized. The antibacterial and antifungal activities of the synthesized these compounds were investigated in vitro against some human pathogens (Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and Candida albicans, C. tropicalis, C. guilliermondii and C. glabrata). Test microorganisms were isolated from the patients appyling to Medical Faculty Hospital of Duzce University were used. Diffusion method was used to determine the antimicrobial activities of the compounds. standard antibacterial (Cefotaxime, Amoxicillin/clavulanicacid) and antifungal (Posaconazole) antibiotics were used as the control group and the results were compared. The result indicated that antimicrobial activity of Disulphide-Schiff Base Derivatives exhibited less activity against bacteria as compared to AMC30 (Amoxicillin/clavulanicacid), but highly effective against bacteria as compared to CTX30 (Cefotaxime). In addition, the compounds exhibited less activity against yeast.Öğe Synthesis of disulphide-Schiff base derivatives, investigation of their antibacterial and anti-candidal activities(Elsevier Science Bv, 2017) Dalmaz, Aslıhan; Durmuş, Sefa; Dülger, Görkem; Kadıoğlu, Duygu Bircan…Öğe Synthesis of Nano Poly(2-thiophenecarboxaldehyde) and Characterization of Structure(2018) Sivrikaya, Sezen; Dalmaz, Aslıhan; Durmuş, SefaThis 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.Öğe Synthesis, characterization and electrochemical behavior of some Ni(II), Cu(II), Co(II) and Cd(II) complexes of ONS type tridentate Schiff base ligand(Pergamon-Elsevier Science Ltd, 2011) Durmuş, Sefa; Atahan, Alparslan; Zengin, MustafaTridentate Schiff base (H2L) ligand was synthesized via condensation of o-hydroxybenzaldehyde and 2-aminothiophenol. The metal complexes were prepared from reaction of the ligand with corresponding metal salts presence of substituted pyridine in two different solvents (MeOH or MeCN). The ligand and metal complexes were then characterized by using FTIR, TGA, H-1 NMR and C-13 NMR spectroscopies. The FTIR spectra showed that H2L was coordinated to the metal ions in tridentate manner with ONS donor sites of the azomethine N, deprotonated phenolic-OH and phenolic-SH. Furthermore, substituted pyridine was coordinated to the central metal atoms. The thermal behavior of the complexes was investigated by using TGA method and dissociations indicated that substituted pyridine and ligand were leaved from coordination. This coordination of the metal complexes was correlated by H-1 NMR and C-13 NMR. Finally, electrochemical behavior of the ligand and a Ni(II) complex were investigated. (C) 2011 Elsevier B.V. All rights reserved.Öğe Synthesis, characterization, crystal structure, magnetic studies of a novel polymeric zig-zag chain copper (II) complex(Elsevier Science Sa, 2014) Yardan, Alper; Yahşi, Yasemin; Kara, Hülya; Karahan, Ahmet; Durmuş, Sefa; Kurtaran, RaifA single crystal of copper (II) complex (1) has been synthesized and its crystal structure has been determined by single crystal X-ray diffraction analysis and characterized by elemental analyses, IR spectroscopy, thermal analysis, H-1 NMR and C-13 NMR spectroscopy. The complex crystallizes in orthorombic space group Pnma, with unit cell dimensions a = 9.8944, b = 25.2972, c = 7.4457 angstrom, ss = 90 degrees. Structural analysis of (1) shows that the Schiff base ligand coordinates toward one metal atom in a pentadentate mode and each Cu atom is six-coordinated. The aliphatic oxygen atom of Schiff base ligand links the [CuL] moieties and creates polymeric zig-zag chain structure. In addition, magnetic susceptibilities for complex (1) have been measured over the temperature range 2-300 K and the magnetic parameters have been determined with fitting procedure. Magnetic measurements on (1) reveal the presence of antiferromagnetic exchange interactions between Cu(II) ions in the dimeric unit via bridging oxygen atoms of pentadentate Schiff base ligand. (c) 2014 Elsevier B.V. All rights reserved.Öğe Thio-Schiff bases derived from 2,2 '-disulfanedianiline via nanocerium oxide: antimicrobial effect and antiproliferative effects in melanoma cells(Scientific and Technological Research Council Turkey, 2022) Dalmaz, Aslıhan; Durmuş, Sefa; Dülger, Görkem; Alpay, MerveIn this study, the synthesis of dimeric disulfide-Schiff bases was carried out using two methods. The structures of the obtained Schiff bases were elucidated by various spectroscopic methods as well as elemental analysis. The Schiff base derivative compounds (3a-6) were screened for in vitro antibacterial activity against multidrug-resistant microorganisms using microdilution method. All the tested compounds showed varying inhibition zones against the pathogens. According to MIC results, the compound 2 was shown strong inhibitory activity against all the tested microorganisms compared to antibiotics. In addition, all the tested compounds showed different antiproliferative effects on the melanoma cell line (B16F10). Our synthesized dimeric disulfide-Schiff bases have shown significant various effects.Öğe Ticari Bal Kullanılarak ZnO Nanopartiküllerinin Yeşil Sentezi, Yapısal Karakterizasyonu ve Biyolojik Aktivitelerinin İncelenmesi(Düzce Üniversitesi, 2023) Gençay, Simge Nur; Durmuş, Sefa; Dalmaz, Aslıhan; Dulger, GorkemNanopartiküllerin sentezi, yeni teknolojilerin geliştirilmesiyle birlikte ilgili potansiyel uygulamalar için yeni bir araştırma alanıdır; özellikle, çevre dostu nanomalzemeler, nanobilim içinde büyüyen bir alan haline gelmiştir. Son zamanlarda, bitki özleri ve arı ürünleri kullanılarak metal oksit nanopartiküllerin sentezi, nanobilim ve nanobiyoteknoloji alanında, geleneksel fizikokimyasal yaklaşımlara göre sayısız avantajlarla ilgi çekici bir konu olarak ortaya çıkmıştır. Bu çalışmada, çinko oksit nanopartiküllerin (ZnO NP’in) sentezi için, kestane (Castanea sativa) balı kullanarak yeni, "daha yeşil", biyolojik olarak yönlendirilmiş, düşük maliyetli ve çevre dostu bir yöntem geliştirildi. ZnO NP'lerin sentezi için öncü bileşik olarak ticari kestane balı kullanılırken, metal tuzu olarak ise çinko nitrat hekzahidrat kullanıldı. ZnO NP’nin yapıları, Fourier Dönüşümü Kızılötesi Spektroskopisi (FT-IR), X-ışını Kırınımı (XRD), Taramalı Elektron Mikroskobu (SEM) ve Enerji Dağılımlı X-ışını analizi ile araştırıldı. Elde edilen ZnO NP’nin bakteri ve funguslara karşı antimikrobiyal aktiviteleri kuyu difüzyon yöntemi ile ölçüldü ve sonuçlar kaydedildi.Öğe Two New Co(II) Complexes with NNN Type Pyrazol Ligands(Int Union Crystallography, 2010) Atakol, Orhan; Öz, Sevi; Svoboda, Ingrid; Durmuş, Sefa; Kurtaran, Raif; Arıcı, Cengiz…
