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    1,1?-(Piperazine-1,4-diyl)dipropan-2-ol
    (Int Union Crystallography, 2011) Turkyilmaz, Murat; Baran, Yakup; Ozdemir, Namik
    The asymmetric unit of the crystal contains one-fourth of the title compound, C10H22N2O2, with the centre of the piperazine ring located at a site of 2/m symmetry. The piperazine ring adopts a chair conformation. The methine and methylene C atoms of the 2-hydroxypropyl groups show symmetry-imposed disorder over two equally occupied and mutually exclusive sets of positions. Only intramolecular O-H center dot center dot center dot N contacts are observed.
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    (2,6-bis{1-[4-(dimethylamino)phenylimino]ethyl}pyridine)dichlorido(tri-phenylphosphine-?P)ruthenium(II): a zigzag chain of fused centrosymmetric R22(12) rings
    (Int Union Crystallography, 2007) Ozdemir, Namik; Dincer, Muharrem; Dayan, Osman; Cetinkaya, Bekir
    The title compound, [RuCl2(C25H29N5)(C18H15P)], a transfer hydrogenation catalyst, is supported by an N,N',N-tridentate pyridine-bridged ligand and triphenylphosphine. The Run centre is six-coordinated in a distorted octahedral arrangement, with the two Cl atoms located in the axial positions, and the pyridine (py) N atom, the two imino N atoms and the triphenylphosphine P atom located in the equatorial plane. The two equatorial Ru-N-imino distances (mean 2.093 angstrom) are substantially longer than the equatorial Ru-N-py bond [1.954 (4) angstrom]. It is observed that the N-imino-M-N-py bond angle for the five-membered chelate rings of 2,6-bis(imino)pyridine-based complexes is inversely related to the magnitude of the M-N-py bond. The title structure is stabilized by intra- and intermolecular C-H... Cl hydrogen bonds, as well as by intramolecular pi-pi stacking interactions between the aromatic rings belonging to the triphenylphosphine ligand and the dimethylaminophenyl fragment. The intermolecular 2 hydrogen bonds form an R-2(2)(12) ring and a zigzag chain of fused centrosymmetric rings running parallel to the [100] direction.
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    2-[2-(1H-Imidazol-3-ium-5-yl)ethyl]-3-(pyridin-2-yl)-2H-imidazo[1,5-a]pyridin-4-ium bis(perchlorate)
    (Int Union Crystallography, 2011) Turkyilmaz, Murat; Baran, Yakup; Ozdemir, Namik
    In the title molecular salt, C17H17N5+center dot 2ClO(4), the dihedral angles between the fused-ring system and the pendant five- and six-membered heterocyclic rings are 6.4 (2) and 41.29 (19)degrees, respectively. The O atoms of both perchlorate anions are disordered over two sets of sites with occupancy ratios of 0.614 (8):0.386 (8) and 0.591 (7):0.409 (7). An intramolecular C-H center dot center dot center dot N contact occurs in the cation. In the crystal, the components are linked by N-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds and pi-pi stacking interactions [centroid-centroid separation = 3.642 (3) angstrom].
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    (2Z,6Z)-N2,N2?-bis(2,6-diisopropylphenyl)-N1,N1?-bis(2-methoxyethyl)pyridine-2,6-dicarboxamidine
    (Int Union Crystallography, 2008) Dincer, Muharrem; Ozdemir, Namik; Dayan, Osman; Cetinkaya, Bekir
    In the title compound, C37H53N5O2, the benzene rings make dihedral angles of 84.61 (8) and 67.10 (9)degrees with the pyridine ring. The crystal structure is stabilized by strong intramolecular interactions. The two (2-methoxyethyl) amine groups are disordered over two positions; the site occupancies are ca 0.6 and 0.4.
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    A hydrazine-bridged dinuclear ruthenium complex: Structural properties and biological activity
    (Elsevier, 2023) Erdener, Digdem; Dervisoglu, Gokhan; Ozdemir, Fethi Ahmet; Serbetci, Zafer; Ozdemir, Namik; Dayan, Osman
    In this study, a new dimeric Ru(II) complex, [Ru(eta(6)-p-cymene)Cl-2](2) (mu(2)-N-2 H-4) (C1), readily synthesized with a reaction of hydrazine hydrate as ligand and [RuCl2(p-cymene)](2) dimmer in dichloromethane. The C1 complex was characterized structurally using IR, NMR, thermal gravimetry and single-crystal X-ray diffraction and theoretically using DFT techniques. Additionally, electrochemical, and optical properties were investigated in cyclic voltammetry and UV-visible spectroscopy. Furthermore, the C1 complex exhibited great antibacterial activity towards 16 Gram + and Gram - species and cell cytotoxicity towards human SH-SY5Y neuroblastoma cell, DU-145 prostate cancer cell, and A549 lung cancer cell lines. (c) 2022 Elsevier B.V. All rights reserved.
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    A neutral arene ruthenium(II) complex with a sulfonated N,O-chelating ligand: Synthesis, characterization, in vitro cytotoxicity and antibacterial activity
    (Pergamon-Elsevier Science Ltd, 2020) Selvi, Gizem; Ozdemir, Fethi Ahmet; Aykutoglu, Gurkan; Ozdemir, Namik; Serbetci, Zafer; Cetinkaya, Bekir; Dayan, Osman
    In this work, a new N,O-type ligand (L1H) containing a sulfonate ester group and its heteroleptic Ru(II) complex (C1) have been prepared and structurally characterized by various techniques, such as UV-vis, ESI-MS, NMR and IR. The spectroscopic results (IR, UV-vis and NMR) were compared with the results of density functional theory (DFT) calculations. The solid-state structures of L1H and C1 were crystallographically verified. Moreover, the in vitro cytotoxicity and antibacterial properties of 1, L1H and Cl have been screened. All the compounds exhibited good cytotoxicity towards human neuroblastoma cancer cells and antibacterial effects towards 16 bacterial strains, both gram positive and negative. The results revealed that the Ru(II) complex exhibits higher biological activities than the starting materials 1 and L1H. (C) 2019 Elsevier Ltd. All rights reserved.
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    A new phosphazene derivative, spiro-N3P3[(O2C12H8)2(OC6H6N-3)2], and its Ru(II) complex: Syntheses, crystal structure, catalytic activity and antimicrobial activity studies
    (Pergamon-Elsevier Science Ltd, 2015) Cirali, Digdem Erdener; Dayan, Osman; Ozdemir, Namik; Hacloglu, Nurcihan
    A cyclotriphosphazene ligand containing the spirocyclic 2,2'-dioxybiphenyl group and 2-methy1-3-pyridyloxy moieties was synthesized. A Ru(11) complex was prepared from the reaction of [RuCl2(p-cymene)](2) with this ligand. The structures of the ligand and the Ru(II) complex were characterized by FT-IR, H-1 and P-31 NMR spectroscopy. In addition, the molecular structure of the ligand was confirmed by X-ray crystallography. The Ru(II) complex was used as catalyst for the Catalytic Transfer Hydrogenation (CTH) of p-substituent acetophenone derivatives in the presence of KOH. The antimicrobial activities of the ligand and the complex have also been studied. The antimicrobial activities have been screened in vitro against Gram-positive (Staphylococcus aureus ATCC 6538, Bacillus cereus ATCC 7064, Listeria monocytogenes ATCC 15313, Micrococcus luteus La 2971) and Gram-negative (Escherichia coil ATCC 11230, Klebsiella pneumoniae UC57, Pseudomonas aeruginosa ATCC 27853, Proteus vulgaris ATCC 8427, Enterobacter aerogenes ATCC 13048) bacteria and yeast cultures (Candida albi cans ATCC 10231, Kluyveromyces fragills NRRL 2415, Rhodotorula rubra DSM 70403) using both the disk diffusion and dilution methods. (C) 2015 Elsevier Ltd. All rights reserved.
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    (Acetonitrile){2,6-bis[1-(2,4,6-trimethylphenylimino)ethyl]pyridine} dichloridoruthenium(II) dichloromethane solvate
    (Int Union Crystallography, 2007) Ozdemir, Namik; Dincer, Muharrem; Dayan, Osman; Cetinkaya, Bekir
    In the title compound, [RuCl2(C2H3N)(C27H31N3)] center dot CH2Cl2, the Ru-II ion is six-coordinated in a distorted octahedral arrangement, with the two Cl atoms located in the apical positions, and the pyridine (py) N atom, the two imino N atoms and the acetonitrile N atom located in the basal plane. The two equatorial Ru - N-imino distances are almost equal ( mean 2.087 angstrom) and are substantially longer than the equatorial Ru - N-py bond [1.921 ( 4) angstrom]. It is observed that the N-imino-M-N-py angle for the five-membered chelate rings of pyridine-2,6-diimine complexes is inversely related to the magnitude of the M-N-py bond. The title structure is stabilized by intra- and intermolecular C-H center dot center dot center dot Cl hydrogen bonds, as well as by van der Waals interactions.
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    Bis{2,6-bis[1-(4-fluorophenylimino)ethyl]pyridine}-1?3N,N?,N;3?3N,N?,N-di-?-chlorido-1:2?2Cl:Cl;-2:3?2Cl:Cl-trichlorido-1?Cl,2?Cl,3?Cl-2-copper(I)-1,3-dicopper(II)
    (Int Union Crystallography, 2008) Ozdemir, Namik; Dincer, Muharrem; Dayan, Osman; Cetinkaya, Bekir
    The title complex, [Cu3Cl5(C21H17N3F2)(2)], is the first reported copper trimer including both Cu-I and Cu-II ions. The two Cu-II ions are five-coordinate in a significantly distorted square-pyramidal arrangement, with the bridging Cl atom located in the apical position, and the pyridine (py) N atom, the two imine N atoms and the other Cl atom located in the basal plane. The Cu-I ion is in a trigonal planar configuration surrounded by three Cl atoms. The structure is stabilized by intra- and intermolecular C-H center dot center dot center dot Cl and C-H center dot center dot center dot pi(py) hydrogen bonds.
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    Concomitant polymorphism of a pyridine-2,6-dicarboxamide derivative in a single space group: Experimental and molecular modeling study
    (Pergamon-Elsevier Science Ltd, 2012) Ozdemir, Namik; Dayan, Osman; Cetinkaya, Bekir; Akgul, Cahit
    The title compound, N-2,N-6-bis{2-[(Z)-2-hydroxybenzylideneamino]phenyl}pyridine-2,6-dicarboxamide (3), has been synthesized by the reaction of 2-{(2-aminophenylimino)methyl}phenol (1) with pyridine2,6-dicarbonyl dichloride (2), and characterized by elemental analysis. FT-IR and NMR spectroscopies and thermal analysis. Compounds 1 and 3 were evaluated for their antibacterial activities against Grampositive and Gram-negative bacteria. The catalytic activity of 3 was also studied, and as a result, the in situ prepared three component system Ru(II)/3/KOH is shown to be an efficient catalyst for the transfer hydrogenation reaction of various ketones under mild conditions. Compound 3 has been crystallized in two polymorphic forms under the same conditions, and their crystal structures have been determined using single crystal X-ray diffraction technique. The molecular geometry, vibrational frequencies and gauge-independent atomic orbital (CIAO) H-1 and C-13 NMR chemical shift values of 3 in the ground state have been calculated using the density functional theory (DFT/B3LYP) method with the 6-31G(d) basis set, and compared with the experimental data. The results are in good agreement with experimental data. The effect of different solvents on the geometry, vibrational frequencies, total energies and dipole moments was also studied using the same method by applying the Onsager Model. There are subtle differences in the conformations and packing of the two polymorphs as a consequence of intermolecular hydrogen bonding interactions. Therefore, DFT calculations for the hydrogen bond interactions in the polymorphs were carried out using same basis set. The changes of thermodynamic properties from the monomers to 3 with the temperature ranging from 200 K to 400 K have been obtained using the statistical thermodynamic method. (C) 2011 Elsevier B.V. All rights reserved.
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    Direct and solvent-assisted thione-thiol tautomerism in 5-(thiophen-2-yl)-1,3,4-oxadiazole-2(3H)-thione: Experimental and molecular modeling study
    (Elsevier, 2014) Arslan, N. Burcu; Ozdemir, Namik; Dayan, Osman; Dege, Necmi; Koparir, Metin; Koparir, Pelin; Muglu, Halit
    The compound has been synthesized and characterized by IR, NMR and X-ray diffraction. Quantum chemical calculations at B3LYP/6-311++G(d,p) level were performed to study the molecular and spectroscopic properties, conformational equilibrium, thione <-> thiol tautomerism and intermolecular double proton transfer reaction of the compound. The obtained structural and spectroscopic results are well in agreement with the experimental data. The solvent effect on the proton transfer reaction was investigated in three solvents using the polarizable continuum model approximation and solvent-assisted mechanism. The anti-thione tautomer is the most stable isomer among the four possible structural forms both in the gas phase and in solution phase. A high tautomeric energy barrier is found for the tautomerism between the anti and syn forms of the compound, indicating a quite disfavored process. Although the presence of one methanol or water solvent molecule significantly lowers the energy barrier, it is not adequate for the reaction to occur. (C) 2014 Elsevier B.V. All rights reserved.
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    Enol-imine/keto-amine tautomerism of (E)-4-[(2-hydroxybenzylidene)amino]phenyl benzenesulfonate
    (Int Union Crystallography, 2016) Dincer, Muharrem; Ozdemir, Namik; Kagit, Reyhan; Dayan, Osman
    [Anstract Not Available]
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    Experimental and molecular modeling investigation of (E)-N-{2-[(2-hydroxybenzylidene)amino]phenyl}benzenesulfonamide
    (Taylor & Francis Ltd, 2013) Ozdemir, Namik; Dayan, Serkan; Dayan, Osman; Dincer, Muharrem; Kalaycioglu, Nilgun O.
    The Schiff base compound (E)-N-{2-[(2-hydroxybenzylidene)amino]phenyl}benzenesulfonamide has been synthesized and characterized by IR, NMR and Uv-vis spectroscopies, and single-crystal X-ray diffraction technique. In addition, quantum chemical calculations employing density functional theory (DFT) method with the 6311++G(d,p) basis set were performed to study the molecular, spectroscopic and some electronic structure properties of the title compound, and the results were compared with the experimental findings. There exists a good correlation between experimental and theoretical data. Enol-imine/keto-amine tautomerization mechanism was investigated in the gas phase and in solution phase using the polarizable continuum model (PCM) approximation. The energetic and thermodynamic parameters of the enol-imineketo-amine transfer process show that the single proton exchange is thermodynamically unfavored both in the gas phase and in solution phase. However, the reverse reaction seems to be feasible with a low barrier height and is supported by negative values in enthalpy and free energy changes both in the gas phase and in solution phase. The solvent effect is found to be sizable with increasing polarity of the solvents for the reverse reaction. The predicted nonlinear optical properties of the compound are found to be much greater than those of urea.
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    Heteroleptic ruthenium(II) complexes of 2-(2-pyridyl)benzimidazoles: A study of catalytic efficiency towards transfer hydrogenation of acetophenone
    (Pergamon-Elsevier Science Ltd, 2015) Dayan, Osman; Demirmen, Selin; Ozdemir, Namik
    Six ruthenium(II) complexes ([RuCl2(p-cymene)(L1-6)], SD1-6, (L1-6: bidentate pyridyl-benzimidazole ligands)) were synthesized from [RuCl2(p-cymene)](2) dimer and bidentate pyridyl-benzimidazole ligands. The compounds were characterized by elemental analysis, IR, UV-Vis, NMR and X-ray diffraction. The synthesized Ru(II) complexes (SDI-6) were tested as catalysts for the catalytic transfer hydrogenation (CH) of acetophenone to secondary alcohols in the presence of KOH using 2-propanol as a hydrogen source at 82 degrees C. All complexes were active catalysts for TM of acetophenone with good yields under mild conditions (after 15 min, yields of up to 91%). (C) 2014 Elsevier Ltd. All rights reserved.
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    Investigation of enol-imine/keto-amine tautomerism in (E)-4-[(2-hydroxybenzylidene)amino]phenyl benzenesulphonate by experimental and molecular modelling methods
    (Taylor & Francis Ltd, 2016) Ozdemir, Namik; Kagit, Reyhan; Dayan, Osman
    The Schiff base compound (E)-4-[(2-hydroxybenzylidene)amino]phenyl benzenesulphonate has been synthesised from the reaction of 4-aminophenyl benzenesulphonate and salicylaldehyde, and characterised by spectroscopic and single-crystal X-ray diffraction techniques. Quantum chemical calculations employing density functional theory method with the 6-311++G(d,p) basis set were performed to study the molecular, spectroscopic and enol-imine/keto-amine tautomerisation mechanism of the title compound. An acceptable correlation between experimental and theoretical findings is obtained. Enol-imine/keto-amine tautomerisation mechanism was investigated in the gas phase and in solution phase using the polarisable continuum model approximation. The energetic and thermodynamic parameters of the enol-imine -> keto-amine transfer process show that the single proton exchange is unfavoured in all cases. Contrarily, the reverse reaction seems to be feasible with a very low barrier height and is supported by negative values in enthalpy and free energy changes for all cases.
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    Nickel (II) complex [NiCl2(DMF)2L2] bearing diaminobenzene and sulfonamide: Crystal structure and catalytic application in the reduction of nitrobenzenes
    (Pergamon-Elsevier Science Ltd, 2020) Dayan, Serkan; Kayaci, Nilgun; Dayan, Osman; Ozdemir, Namik; Ozpozan, Nilgun Kalaycioglu
    A new Bis[N-(2-aminophenyl)benzenesulfonamidej-di-chloro-Bis[O'-N,N-dimethyl-formamide]-nickel (II) complex [NiCl2(DMF)(2)L2] was synthesized in DMF solution in reflux media with NiCl2.2H(2)O and the pre-prepared N-(2-aminophenyl)benzenesulfonamide and the [NiCl2(DMF)(2)L-2] complex was crystallized in DMF/diethyl ether solution, for its single crystal. The complex characterized by FT-IR, elemental analysis, TG-DTA and UV Vis spectrophotometry methods, and its single crystal study were also performed by X-ray spectroscopy. Additionally, the catalytic efficiency of the fabricated [NiCl2(DMF)(2)L-2] complex was determined by UV Vis spectrophotometry in the reduction reaction of 2-nitroaniline (2-NA), 4-nitroaniline (4-NA) and nitrobenzene (NB) in presence of NaBH4 in water. The best conversion obtained as a result of the reduction of nitroarenes in the short time of 10 min. was 62.5 %, which was obtained at the 2-NA reduction. The conversion obtained from of the reduction of nitroarenes, are sequenced as 2-NA (62.5 %) > NB (56.5 %) > 4-NA (25.5%) in 10 min. In addition, the reaction products, both aqueous and short-term, are harmless to the environment, which will provide a significant reaction variety in terms of green chemistry. (C) 2019 Elsevier Ltd. All rights reserved.
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    One-pot stepwise reductive amination reaction by N-coordinate sulfonamido-functionalized Ru(II) complexes in water
    (Wiley, 2018) Kayaci, Nilgun; Dayan, Serkan; Ozdemir, Namik; Dayan, Osman; Ozpozan, Nilgun Kalaycioglu
    New complexes of formula [RuCl(p-cymene)(L)] (7-12) were prepared with [RuCl2(p-cymene)](2) and pre-synthesized N-arenesulfonly-o-phenylenediamines (1-6) and characterized using H-1 NMR, C-13 NMR, Fourier transform infrared and UV-visible spectroscopic techniques, and single-crystal X-ray diffraction analysis was performed for one complex (8). Complexes 7-12 were investigated in the reduced imine synthesis reaction (in the presence of HCOONa/HCOOH). The best turnover frequency values were found to be 100 h(-1) for 1 and 99 h(-1) for 6 in the transfer hydrogenative reductive amination reaction of 4-methoxyaniline and 3,4,5-trimethoxybenzaldehyde. The most important feature of this reaction is that it is an environmental friendly procedure because of being conducted in an aqueous environment. That no organic solvent is used allows one to say that this reaction represents green chemistry.
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    Palladium(II) complexes assembled on solid materials: as catalysts for the -NO2 (nitro) to -NH2 (amine) reactions
    (Springer Wien, 2020) Dayan, Serkan; Kayaci, Nilgun; Ozdemir, Namik; Dayan, Osman; Kalaycioglu Ozpozan, Nilgun
    Herein, a new series of [PdCl2(L)(2)] complexes where ligands are monodentate amine ligands bearing sulfonamide groups were synthesized, characterized using various techniques such as NMR, FT-IR, UV-Vis, and sc-XRD and investigated for their catalytic performance for the reduction of nitroarenes (2-nitroaniline, 4-nitroaniline, and nitrobenzene) in the presence of NaBH4 in water under heterogeneous conditions. Because the results show that the synthesized complexes are very efficient catalysts, materials using the selected palladium(II) complex supported by multiwall carbon nanotubes, silicon dioxide, and iron(II,III) oxide (Fe3O4) were fabricated by a simple-impregnation methodology, characterized by FT-IR, BET, TEM, and XRD techniques and investigated for their catalytic performance for the same reaction. Thus, a series of supported catalysts was designed with the aim of both enhancing catalytic activity and reducing noble-metal contents. Our findings serve to develop simple catalytic systems and this system can be easily used for catalytic reduction reactions which are the cornerstone of the production of important chemicals. [GRAPHICS] .
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    Palladium(II) complexes bearing bidentate pyridyl-sulfonamide ligands: Synthesis and catalytic applications
    (Pergamon-Elsevier Science Ltd, 2015) Dayan, Serkan; Cetin, Ahmet; Arslan, N. Burcu; Ozpozan, Nilgun Kalaycoiglu; Ozdemir, Namik; Dayan, Osman
    New palladium(II) complexes aPd(1-5)(2)], 6-10, (1-5 = bidentate pyridyl-sulfonamide ligands)) were obtained from the reaction between Pd(OAc)(2) and bidentate pyridyl-sulfonamide ligands. The synthesized compounds were characterized by elemental analysis, TG, NMR, IR and X-ray diffraction. The Pd(II) complexes 6-10 were investigated as catalysts for the oxidation of benzyl alcohol to benzaldehyde in the presence of periodic acid as the oxidant and acetonitrile as the solvent under reflux. All the complexes were moderately active catalysts for the catalytic reaction (the oxidation of benzyl alcohol to benzaldehyde), with good yields under mild conditions. (C) 2014 Elsevier Ltd. All rights reserved.
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    Photoresponsivity and photodetectivity properties of copper complex-based photodiode
    (Elsevier, 2020) Dayan, Osman; Imer, Arife Gencer; Al-Sehemi, Abdullah G.; Ozdemir, Namik; Dere, A.; Serbetci, Z.; Al-Ghamdi, Ahmed A.
    Spin coated Cu(II) complex thin layer onto p-Si substrate was used in photodiode fabrication. The structural properties of novel synthesized Cu(II) complex were investigated using different techniques. The single crystal X-ray diffraction (sc-XRD) technique confirms the Cu(II) complex containing 2-mesityl1H-benzo[d]imidazole ligands and two chloride ligands have a highly distorted cis-square-planar geometry. The thermogravimetric analysis (TGA) shows that the Cu(II) complex is stable up to 248 degrees C. Also, the current-voltage measurements were performed to investigate the characteristic of photodiode based on copper complex in darkness and under solar simulator. The fundamental electrical parameters of fabricated diode were obtained using Thermionic theory and modified Norde function. The manufactured device exhibits a good response to light with the defined rise and fall time of 351 ms and 622 ms under 100 mWcm(-2) solar illumination, respectively. Furthermore, frequency dependent capacitance and conductance measurements were performed in dark and under illumination. The obtained results suggest that prepared photodiode based on Cu(II) complex could be used for organic light detection in different optoelectronic applications as photodetector, photocapacitor, and photoconductor. (C) 2019 Elsevier B.V. All rights reserved.