Browsing by Author "Ataç A."
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Item Structural characterization and luminescence properties of an isonicotinic acid N-oxide Mn(II) complex(Elsevier Ltd, 2004) Can N.; Sözerli Can S.E.; Ataç A.; Bardak F.An isonicotinic acid N-oxide Mn(II) compound was synthesized and characterized on the basis of elemental analysis and X-ray crystallography. In the complex, Mn(II) ions are coordinated by six water molecules, and the coordination number of the Mn(II) ion is six. FTIR spectra of the compound free isonicotinic acid N-oxide (INO) have been recorded in the range 4000-400 cm -1. Cathodoluminescence (CL) spectra from the Mn(II) complex have been recorded. The luminescence data were interpreted in terms of the emission band at 480 nm. The green luminescence (∼480 nm) arises from the Mn 2+ transition 4T1 (4G) →6A1 (6S). It shows weak vibronic structure, short lifetimes less than 250 μs, and indicates that Mn 2+ is octahedrally coordinated, occupying sites with similar distortions. The lifetime and intensity of the signal is temperature dependent, and the parameters are reported for the 480 nm emission line. © 2004 Elsevier Ltd. All rights reserved.Item Spectroscopic and luminescence properties of an isonicotinic acid(2005) Can N.; Ataç A.; Bardak F.; Sözerli Can Ş.E.An isonicotinic acid N-oxide Zn(II) compound was characterized on the basis of elemental analysis. FTIR spectra of the compound and free isonicotinic acid N-oxide (INO) were recorded in the range 4000-400 cm-1. Cathodoluminescence (CL) spectra from the Zn(INO)2 complex were recorded. The luminescence data were interpreted in terms of the emission band at 470 nm. The green luminescence (∼ 470 nm) arises from Zn2- transition 4T1(4G) → 6A 1 (6S). It shows a weak vibronic structure, and short lifetimes less than 150 μs. The lifetime and intensity of the signal are temperature dependent, and the parameters are reported for the 470 nm emission line. © TÜİTAK.Item Synthesis and vibrational spectroscopic study of some metal(II) halide and tetracyanonickelate complexes of isonicotinic acid(2006) Ataç A.; Bardak F.The M(IN)2Ni(CN)4 [where M: Cu, Mn, Zn, IN: Isonicotinic acid, abbreviated to M-Ni-IN] tetracyanonickelate and some metal halide complexes with the following stoichiometries: Cu(IN)X2 (X:Br,I), Cd(IN)2X2, (X:Cl,Br), and Zn(IN) 4X2 (X:Br,I) were synthesized for the first time. Their FT-IR spectra were reported in the 4000-400 cm-1 region. Vibrational assignments were given for all the observed bands. The analysis of the vibrational spectra indicates that there are some structure-spectrum correlations. For a given series of isomorphous complexes, the sum of the difference between the values of the vibrational modes of uncoordinated isonicotinic acid that were coordinated to the metal ion isonicotinic acid was investigated and found to depend on the halogen for a given metal. The proposed structure of tetracyanonickelate complexes consists of polymeric layers of |M-Ni(CN)4|∞ with the isonicotinic acid molecules bound directly to the metal (M) atoms. Certain chemical formulae were determined using the elemental analysis results. © TÜBİTAK.Item Synthesis and vibrational spectroscopic studies of isonicotinamide metal(II) halide complexes(2006) Ataç A.; Yurdakul S.; Ide S.Fourier transform infrared spectra (4000-200 cm-1) are reported for the metal (II) halide isonicotinamide complexes of the following stoichiometries: M(iso)2X2 [MNi, Cu, Hg; XCl; iso=isonicotinamide], M(iso)2X2 [MNi, Cu; XBr], and Co(iso)2I2. Vibrational assignments are given for all the observed bands. The Raman spectra (4000-100 cm-1) are reported for the three of these complexes. Also, the ESR spectra of these complexes are given. For a given series of isomorphous complexes the sum of the difference between the values of the vibrational modes of the free isonicotinamide and complexed ligand was found to increase in the order of the second ionization potentials of metals. The frequency shifts are also found to depend on the halogen. The studied metal halide complexes were characterized by X-ray powder diffraction patterns and FTIR spectra. Certain chemical formulas were determined using elemental analysis results. Finally, the geometry optimization method was used to predict three dimensional molecular geometries of the complexes by using the HYPERCHEM 5.0 the level of the theory molecular mechanic. © 2005 Elsevier B.V. All rights reserved.Item Experimental and theoretical FT-IR and FT-Raman spectroscopic analysis of N1-methyl-2-chloroaniline(2009) Karabacak M.; Kurt M.; Ataç A.In this work, the experimental and theoretical vibrational spectra of N1-methyl-2-chloroaniline (C7H8NCl) were studied. FT-IR and FT-Raman spectra of the title molecule in the liquid phase were recorded in the region 4000-400 cm-1 and 3500-50 cm-1 respectively. The structural and spectroscopic data of the molecule in the ground state were calculated by using density functional method (B3LYP) with the 6-311+++G (d, p) basis set. The vibrational frequencies were calculated and scaled values were compared with experimental FT-IR and FT-Raman spectra. The observed and calculated frequencies are found to be in good agreement. The complete assignments were performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. 13C and 1H NMR chemical shifts results were compared with the experimental values. The optimized geometric parameters (bond lengths and bond angles) were given and are in agreement with the corresponding experimental values of aniline and p-methyl aniline. Copyright © 2008 John Wiley & Sons, Ltd.Item Synthesis, spectroscopy, and characterization of some bis-nicotinamide metal(II) dihalide complexes(2011) Ataç A.; Yurdakul Ş.; Berber S.We report synthesis of six new bis-nicotinamide metal(II) dihalide complexes [M(nia) 2Cl 2; M = Mn, Co; nia:nicotinamide, M(nia) 2Br 2; M = Mn, Hg; M(nia) 2I 2; M = Cd, Cu], and their characterization by combining infrared spectroscopy with density functional theory (DFT) calculations. Infrared spectra indicate that ring-nitrogen is the active donor cite, and the atomic structure of the complexes is determined to be polymeric octahedral or distorted polymeric octahedral. Spin polarized electronic ground state is obtained for Mn, Co, and Cu halide complexes. The colors of the complexes also support the conclusion of octahedral coordination around the metal atoms, in agreement with DFT results. © 2011 Elsevier B.V. All Rights Reserved.Item Mechanical properties and hardness results of the medium frequency induction sintered iron based powder metal bushings(International Institute for the Science of Sintering (IISS), 2014) Çavdar U.; Atik E.; Ataç A.In this study; iron based powder metal (PM) bushing compacts were sintered via medium frequency induction heating system. Iron based powders were mixed with 2 wt.% copper (Cu), 0.3 wt.% carbon (C) and 1 wt.% zinc stearat (Zn-st) via V-Type mixer. PM compacts were sintered by 2 different sintering processes. One of them was conventional sintering method other was medium frequency induction sintering method. In conventional sintering process, PM bushing compacts were sintered under inert environmental at 11200C for 30 minutes. In medium frequency induction sintering process, PM bushing compacts were sintered between 30-50 kHz frequency (Medium frequency) at 2 kW, 11200C for 1 or 3 minutes under atmospheric environmental. Mechanical properties, densities and micro hardness’ were investigated for all sintered processes. SEM and micro structural images were taken from polished broken surface of the sintered PM bushing compacts. 3 minutes induction sintered compacts were reached the compressive strength, microhardness and density values of the conventional sintered PM bushing compact. © 2014,International Institute for the Science of Sintering (IISS). All rights reserved.Item Single and binary nickel, copper, and zinc-based nanosized oxides as anode materials in lithium-ion batteries(Springer, 2024) Egesoy E.; Kap Ö.; Bardak F.; Horzum N.; Ataç A.The demand for portable power sources with higher energy density and longer lifespan has prompted researchers to focus on developing better electrode materials for lithium-ion batteries (LIBs). Metal oxide nanoparticles have potential due to their low cost, high surface-area-to-volume ratio, strong reactivity, excellent size distribution, high theoretical capacities, and eco-friendly synthesis methods. However, there is still room for improvement in capacity retention and rate performance. To cope with this entail, the cycle performance of LIBs has been initially investigated utilizing single metal oxide anode materials including NiO, CuO, and ZnO nanostructures. Subsequently, binary oxides of Ni–Cu, Ni–Zn, and Cu–Zn have been synthesized to examine whether the binary structures boost the battery performance. NiCuO is the optimum anode material combining the benefits of NiO with the highest initial discharge capacity of 691 mAh g - 1 and the highest retention rate of CuO (49% after 30 cycles). © 2024, The Author(s).Item Experimental and computational insights into the electronic structures and absorption-emission characteristics of coumarin, C-6H, C-153, and C-343 dyes(Elsevier B.V., 2025) Karaca Ç.; Bardak F.; Köse E.; Ataç A.This paper explores the electronic structure and spectral characteristics of coumarin (C), C-6H, C-153, and C-343 in the protic polar solvent acetonitrile, combining computational methods via Density Functional Theory (DFT) and time-dependent Density Functional Theory (TD-DFT) with experimental analysis of UV–Vis and fluorescence spectra. The optoelectronic features of C, C-6H, C-153, and C-343 are primarily utilized in the solution phase for various applications, such as lasers and dye-sensitized solar cells. Computational studies were conducted using four different Modal Chemistry methods [MC1: CAM-B3LYP/6-311++G(d.p), MC2: CAM-B3LYP/6-31 + G(d.p), MC3: B3LYP/6-311++G(d.p), and MC4: B3LYP/6-31 + G(d.p)]. The excited state features were investigated based on TD-DFT/Polarizable Continuum Model-Linear Response and TD-DFT/Polarizable Continuum Model-State Specific formalisms. Molecular orbital configurations, molecular electrostatic potentials, and electron density difference isosurface of the dyes were analyzed to uncover the factors influencing the absorption and emission properties. The decomposed UV–Vis and fluorescence spectra of compounds indicate that emission characteristics are complex and contribute to low-lying energy transitions. The state-specific solutions provide more reliable estimates for smaller molecular structures with less intramolecular charge transfer, whereas the linear response approach excels when more electron-donating functional groups are present. The effect of the basis set in determining both absorption and emission features is almost negligible compared to Hartree-Fock exchange contributions in DFT functionals. B3LYP appears to provide satisfactory results for systems where long-range HF exchange is not as crucial. © 2025 Elsevier B.V.