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    A Crystallographic, EPR and DFT Investigations of a Novel Magnetically Silent Mono-atom Acetate-Bridged Binuclear Schiff Base-Copper(II) Complex
    (2017) Demir, Serkan; Yerli, Yusuf; Öztürk, Mustafa; Saral, Hasan; Temel, Ersin; Başgel, Serkan
    A recent example of one-atom acetate bridged symmetric dinuclear copper(II) complexes, Di-µ-acetato-bis{1- ((pyridin-2-ylmethylimino)methyl)naphthoxo}copper(II) ([Cu2(NP)2(Ac)2]•2MetOH(1)) (HNP=1-((pyridin-2- ylmethylimino)methyl)naphthol)) have been prepared and characterized by X-ray crystallography, Elemental analyses, ESI-mass, UV-Vis and IR spectroscopic techniques. Magnetic properties of the complex have been probed by EPR measurements and the presence of spin-only paramagnetism of the compound with none of significant exchange coupling has been demonstrated unlike ferro or antiferromagnetism that was otherwise observed in all other analogous structures previously reported. The existence of a trivial ferromagnetic exchange which is quantitatively ignorable has been suggested by DFT-Broken Symmetry calculations performed at crystallographically characterized experimental geometry.
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    A novel determination of curcumin via Ru@Au nanoparticle decorated nitrogen and sulfur-functionalized reduced graphene oxide nanomaterials
    (Royal Soc Chemistry, 2016) Kotan, Gul; Kardas, Faruk; Yokus, Ozlem Aktas; Akyildirim, Onur; Saral, Hasan; Eren, Tanju; Yola, Mehmet Lutfi
    We report the synthesis of Ru@Au nanoparticle involved L-cysteine functionalized reduced graphene oxide (rGO) composites (NSrGO/Ru@AuNPs). The nanocomposites were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The electrochemical determination of curcumin (CR) has been studied using square wave voltammetry (SWV) on a glassy carbon electrode (GCE) modified with NSrGO/Ru@AuNP composites (NSrGO/Ru@AuNPs/GCE). The effective surface areas (ESAs) of the rGO/GCE and NSrGO/Ru@AuNPs/GCE were calculated to be 347 cm(2) mg(-1) and 1289 cm(2) mg(-1), respectively. These results show that the electrochemical surface area of the NSrGO/Ru@AuNPs/GCE is 3.71 times higher than that of the rGO/GCE. The developed method was also applied successfully for the determination of CR in plasma and the linearity range of CR was 0.001-0.1 nM with a detection limit of 2.0 x 10(-13) M.
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    Direct-methanol Fuel Cell Based on Functionalized Graphene Oxide with Mono-metallic and Bi-metallic Nanoparticles: Electrochemical Performances of Nanomaterials for Methanol Oxidation
    (Wiley-V C H Verlag Gmbh, 2016) Yola, Mehmet Lutfi; Eren, Tanju; Atar, Necip; Saral, Hasan; Ermis, Ismail
    The catalysts based on 2-aminoethanethiol functionalized graphene oxide (AETGO) with several mono-metallic and bi-metallic nanoparticles such as rod gold (rAuNPs), rod silver (rAgNPs), rod gold-platinum (rAu-Pt NPs) and rod silver-platinum (rAg-Pt NPs) were synthesized. The successful synthesis of nanomaterials was confirmed by various methods. The effective surface area (ESA) of the rAu-Pt NPs/AETGO is 1.44, 1.64 and 2.40 times higher than those of rAg-Pt NPs/AETGO, rAuNPs/AETGO and rAgNPs/AETGO, respectively, under the same amount of Pt. The rAu-Pt NPs/AETGO exhibited a higher peak current for methanol oxidation than those of comparable rAg-Pt NPs/AETGO under the same amount of Pt loading.
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    Microwave-assisted synthesis of primary aryl/heteroarylamines via one-pot reductive amination: A convenient and efficient synthetic route
    (Elsevier, 2025) Saral, Hasan; Ozdamar, Ozgur; Bekdemir, Yunus
    Microwave-assisted copper-catalyzed amination process can be established for the conversion of aryl/heteroaryl bromides. The key features of this study include diverse aryl/heteroarylamine synthesis, the catalyst amount, shorter reaction time, high yields, a one-pot procedure, simple and commercially available starting materials, and moderate to good reaction yields. We have shown that using Cu(OAc)2 as a catalyst combined with ethylenediamine as an additive in the ethanol as solvent, greatly improved the reaction time and yield of this system compared to the previously reported conditions. The current catalytic system contributes a valuable route for preparing aminoquinoline and aminoisoquinoline as key precursors to obtain fine chemicals.
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    Platinum nanoparticles involved on nitrogen and sulfur-doped nanomaterial as fuel cell electrode
    (Springer, 2017) Saral, Hasan; Akyildirim, Onur; Yuksek, Haydar; Eren, Tanju
    A fuel cell is an electrochemical cell that converts a source fuel into an electrical current. It generates electricity inside a cell through reactions between a fuel and an oxidant, triggered in the presence of an electrolyte. Fuel cells have been attracting more and more attention in recent decades due to high-energy demands, fossil fuel depletions, and environmental pollution throughout world. In this study, a facile and cost-effective catalysts have been developed on platinum nanoparticles (PtNPs) supported on nitrogen and sulfur-doped nanomaterial (PtNPs-NS). The successful synthesis of nanomaterials and the prepared glassy carbon electrode (GCE) surfaces were confirmed by transmission electron microscope (TEM), X-ray photo electron spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. According to TEM images, the average particle sizes of PtNPs were found to be approximately 20-25 nm. The effective surface areas of NS/GCE and PtNPs-NS/GCE were calculated to be 105 and 518 cm(2)/mg, respectively. The PtNPs-NS/GCE also exhibited a higher peak current for methanol oxidation than those of comparable GCE and NS/GCE, providing evidence for its higher electro-catalytic activity.
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    Platinum nanoparticles supported on nitrogen and sulfur-doped reduced graphene oxide nanomaterial as highly active electrocatalysts for methanol oxidation
    (Springer, 2016) Akyildirim, Onur; Yuksek, Haydar; Saral, Hasan; Ermis, Ismail; Eren, Tanju; Yola, Mehmet Lutfi
    A fuel cell is an electrochemical cell that converts a source fuel into an electrical current. It generates electricity inside a cell through reactions between a fuel and an oxidant, triggered in the presence of an electrolyte. Fuel cells have been attracting more and more attention in recent decades due to high-energy demands, fossil fuel depletions and environmental pollution throughout world. In this study, a facile and cost-effective catalysts have been developed on platinum nanoparticles (PtNPs) supported on nitrogen and sulfur-doped reduced graphene oxide (NSrGO). The successful synthesis of nanomaterials and the prepared glassy carbon electrode (GCE) surfaces were confirmed by transmission electron microscope (TEM), X-ray photo electron spectroscopy (XPS), scanning electron microscope (SEM) and electrochemical impedance spectroscopy (EIS). According to TEM images, the average particle sizes of PtNPs were found to be approximately 15-20 nm. The effective surface areas (ESA) of NSrGO/GCE and PtNPs/NSrGO/GCE were calculated to be 148 and 469 cm(2)/mg, respectively. The PtNPs/NSrGO/GCE also exhibited a higher peak current for methanol oxidation than those of comparable GCE and NSrGO/GCE, providing evidence for its higher electro-catalytic activity.
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    Sensitive analysis of simazine based on platinum nanoparticles on polyoxometalate/multi-walled carbon nanotubes
    (Academic Press Inc Elsevier Science, 2016) Ertan, Bengue; Eren, Tanju; Ermis, Ismail; Saral, Hasan; Atar, Necip; Yola, Mehmet Lutfi
    In this report, a novel molecular imprinted voltammetric sensor based on glassy carbon electrode (GCE) modified with platinum nanoparticles (PtNPs) involved in a polyoxometalate (H3PW12O40, POM) functionalized multi -walled carbon nanotubes (MWCNs) sheets was prepared for the determination of simazine (SIM). The developed surfaces were characterized by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) method. SIM imprinted GCE was prepared via electropolymerization process of 100 mM pyrrole as monomer in the presence of 0.1 M acetate buffer (pH 4.0) containing 25 mM SIM. The linearity range and the detection limit of the developed method were calculated as 1.0 x 10(-19)-5.0 x 10(-9) M and 2.0 x 10(-11) M, respectively. In addition, the voltammetric sensor was applied to wastewater samples. The stability and reproducibility of the voltammetric sensor were also reported. (C) 2016 Elsevier Inc. All rights reserved.
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    Synthesis, spectroscopic characterization and DFT calculations of N-Methyl-2-(2′-hydroxyphenyl)benzimidazole derivatives
    (Elsevier, 2016) Saral, Hasan; Ozdamar, Ozgur; Ucar, Ibrahim; Bekdemir, Yunus; Aygun, Muhittin
    1-Methy1-2-(2'-hydroxyphenyl)benzimidazole (1) and 1-Methy1-2-(2'-hydroxy-4'-methylphenyl)benzimidazole (2) compounds have been synthesized and characterized by XRD, IE-MS, FT-IR, UV Vis and H-1, C-13 NMR techniques. The crystal structure of both compounds is stabilized with very strong O-H center dot center dot center dot N hydrogen-bond and pi-pi interactions. In the compound 1, an infinite chain structure with a trans-zigzag type was formed along the crystallographic 11011 direction. Quantum mechanical calculations of energies, geometries, vibrational wavenumbers, NMR and electronic transitions were carried out by DFT using B3LYP functional combined with 6.31G(d,p) basis set. Calculated bond lengths, bond angles and dihedral angles were only slightly different from the experimental ones. The vibrational study was interpreted by means of potential energy distribution (PED). The electronic absorption spectra of the both compounds were predicted by using the time-dependent DFT methods and good agreement was found between the computational and the experimental values. The chemical shifts (H-1 and (1)3C NMR) and isotropic shielding values were calculated by using the gauge-invariant atomic orbital (GIAO) method. The analyses of HOMO and LUMO have been used to explain the charge transfer within the molecule. (C) 2015 Elsevier B.V. All rights reserved.
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    Synthesis, structural and spectroscopic studies of two new benzimidazole derivatives: A comparative study
    (Elsevier, 2017) Saral, Hasan; Ozdamar, Ozgur; Ucar, Ibrahim
    In the present work, structural and spectroscopic studies on 1-Methyl-2-(2'-hydroxy-4'-chlorophenyl) benzimidazole (1) and 1-Methyl-2-(2'-hydroxy-4'-methoxyphenyl)benzimidazole (2), have been carried out extensively by X-ray diffraction, HRMS, UV-Vis, FT-IR and H-1 and C-13 NMR spectroscopy. The crystal structure of both compounds is stabilized by O-H center dot center dot center dot N hydrogen bond and pi-pi interactions. Contrary to compound 1, the skeleton of compound 2 is considerably deviated from the planarity probably caused by intermolecular hydrogen bonding. The experimental results were compared to the theoretical ones, obtained at DFT level. Ground state geometry, electronic structure, vibrational and NMR spectra have been performed using the B3LYP functional with the 6-31 G(d,p) basis set. It was observed that the bond distances and angles in the both compounds were in good with those of the experiment. The energetic behaviors of the both compounds in methanol solvent were examined using by time-dependent DFT (TD-DFT) method by applying the polarizable continuum model (PCM). Isotropic chemical shifts (C-13 and H-1 NMR) were calculated using the gauge-invariant atomic orbital (GIAO) method. The HOMO and LUMO analyses were used to elucidate information regarding charge transfer within the molecule. (C) 2016 Elsevier B.V. All rights reserved.