MCBÜ Açıkerişim Sistemi :: Browsing by Author "Kose E."

Browsing by Author "Kose E."

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Spectroscopic (NMR, UV, FT-IR and FT-Raman) analysis and theoretical investigation of nicotinamide N-oxide with density functional theory
(2011) Atac A.; Karabacak M.; Kose E.; Karaca C.
The spectroscopic properties of the nicotinamide N-oxide (abbreviated as NANO, C 6H 6N 2O 2) were examined by FT-IR, FT-Raman, NMR and UV techniques. FT-IR and FT-Raman spectra in solid state were observed in the region 4000-400 cm -1 and 3500-50 cm -1, respectively. The 1H and 13C NMR spectra were recorded in DMSO. The UV absorption spectrum of the compound that dissolved in water was recorded in the range of 200-800 nm. The structural and spectroscopic data of the molecule in the ground state were calculated by using Density Functional Theory (DFT) employing B3LYP methods with the 6-311++G(d,p) basis set. The geometry of the molecule was fully optimized, vibrational spectra were calculated and fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. The optimized structure of compound was interpreted and compared with the reported experimental values. The observed vibrational wavenumbers, absorption wavelengths and chemical shifts were compared with calculated values. As a result, the optimized geometry and calculated spectroscopic data show a good agreement with the experimental results. © 2011 Elsevier B.V.
Molecular structure investigation and spectroscopic studies on 2,3-difluorophenylboronic acid: A combined experimental and theoretical analysis
(2012) Karabacak M.; Kose E.; Atac A.; Ali Cipiloglu M.; Kurt M.
This work presents the characterization of 2,3-difluorophenylboronic acid (abbreviated as 2,3-DFPBA, C6H3B(OH)2F 2) by quantum chemical calculations and spectral techniques. The spectroscopic properties were investigated by FT-IR, FT-Raman UV-Vis, 1H and 13C nuclear magnetic resonance (NMR) techniques. The FT-IR spectrum (4000-400 cm-1) and the FT-Raman spectrum (3500-10 cm-1) in the solid phase were recorded for 2,3-DFPBA. The 1H and 13C NMR spectra were recorded in DMSO solution. The UV-Vis absorption spectra of the 2,3-DFPBA that dissolved in water and ethanol were recorded in the range of 200-400 nm. There are four possible conformers for this molecule. The computational results diagnose the most stable conformer of the 2,3-DFPBA as the trans-cis form. The structural and spectroscopic data of the molecule were obtained for all four conformers from DFT (B3LYP) with 6-311++G (d,p) basis set calculations. The theoretical wavenumbers were scaled and compared with experimental FT-IR and FT-Raman spectra. The complete assignments were performed on the basis of the experimental results and total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method, interpreted in terms of fundamental modes. We obtained good consistency between experimental and theoretical spectra. 13C and 1H NMR chemical shifts of the molecule were calculated by using the gauge-invariant atomic orbital (GIAO) method. The electronic properties, such as excitation energies, absorption wavelengths, HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. Finally the calculation results were analyzed to simulate infrared, Raman, NMR and UV spectra of the 2,3-DFPBA which show good agreement with observed spectra. © 2012 Elsevier B.V. All rights reserved.
Synthesis, analysis of spectroscopic and nonlinear optical properties of the novel compound: (S)-N-benzyl-1-phenyl-5-(thiophen-3-yl)-4-pentyn-2-amine
(2012) Karabacak M.; Karaca C.; Atac A.; Eskici M.; Karanfil A.; Kose E.
In this study, a novel compound (S)-N-benzyl-1-phenyl-5-(thiophen-3-yl)-4- pentyn-2-amine (abbreviated as BPTPA) was synthesized and structurally characterized by FT-IR, NMR and UV spectroscopy. The molecular geometry and vibrational frequencies of BPTPA in the ground state have been calculated by using the density functional method (B3LYP) invoking 6-311++G(d,p) basis set. The geometry of the molecule was fully optimized, vibrational spectra were calculated. The fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. Total and partial density of state (TDOS and PDOS) and also overlap population density of state (OPDOS) diagrams analysis were given. The energy and oscillator strength of each excitation were calculated by time-dependent density functional theory (TD-DFT) results complements with the experimental findings. The NMR chemical shifts (1H and 13C) were recorded and calculated using the gauge invariant atomic orbital (GIAO) method. The dipole moment, linear polarizability and first hyperpolarizability values were also computed. The linear polarizability and first hyper polarizability of the studied molecule indicate that the compound is a good candidate of nonlinear optical materials. Finally, vibrational wavenumbers, absorption wavelengths and chemical shifts were compared with calculated values, and found to be in good agreement with experimental results. © 2012 Elsevier B.V. All rights reserved.
Molecular structure (monomeric and dimeric structure) and HOMO-LUMO analysis of 2-aminonicotinic acid: A comparison of calculated spectroscopic properties with FT-IR and UV-vis
(2012) Karabacak M.; Kose E.; Atac A.
The experimental (UV-vis and FT-IR) and theoretical study of 2-aminonicotinic acid (C 6H 6N 2O 2) was presented in this work. The ultraviolet absorption spectrum of title molecule that dissolved in ethanol and water were examined in the range of 200-400 nm. The FT-IR spectrum of the title molecule in the solid state were recorded in the region of 400-4000 cm -1. The geometrical parameters and energies of 2-aminonicotinic acid have been obtained for all four conformers/isomers (C1, C2, C3, C4) from DFT (B3LYP) with 6-311++G(d,p) basis set calculations. C1 form has been identified the most stable conformer due to computational results. Therefore, spectroscopic properties have been searched for the most stable form of the molecule. The vibrational frequencies were calculated and scaled values were compared with experimental FT-IR spectrum. The complete assignments were performed based on the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. Also the molecular structures, vibrational frequencies, infrared intensities were calculated for a pair of molecules linked by the intermolecular OH⋯O hydrogen bond. Moreover, the thermodynamic properties of the studied compound at different temperatures were calculated. Besides, charge transfer occurring in the molecule between HOMO and LUMO energies, frontier energy gap, molecular electrostatic potential (MEP) were calculated and presented. The spectroscopic and theoretical results are compared to the corresponding properties for monomer and dimer of C1 conformer. The optimized bond lengths, bond angles, calculated frequencies and electronic transitions showed the agreement with the experimental results. © 2012 Elsevier B.V. All rights reserved.
Synthesis, spectroscopic characterization and quantum chemical computational studies of (S)-N-benzyl-1-phenyl-5-(pyridin-2-yl)-pent-4-yn-2- amine
(2012) Kose E.; Atac A.; Karabacak M.; Karaca C.; Eskici M.; Karanfil A.
The synthesis and characterization of a novel compound (S)-N-benzyl-1- phenyl-5-(pyridin-2-yl)-pent-4-yn-2-amine (abbreviated as BPPPYA) was presented in this study. The spectroscopic properties of the compound were investigated by FT-IR, NMR and UV spectroscopy experimentally and theoretically. The molecular geometry and vibrational frequencies of the BPPPYA in the ground state were calculated by using density functional theory (DFT) B3LYP method invoking 6-311++G(d,p) basis set. The geometry of the BPPPYA was fully optimized, vibrational spectra were calculated and fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. The results of the energy and oscillator strength calculated by time-dependent density functional theory (TD-DFT) and CIS approach complement with the experimental findings. Total and partial density of state (TDOS and PDOS) and also overlap population density of state (COOP or OPDOS) diagrams analysis were presented. The theoretical NMR chemical shifts (1H and 13C) complement with experimentally measured ones. The dipole moment, linear polarizability and first hyperpolarizability values were also computed. The linear polarizabilities and first hyper polarizabilities of the studied molecule indicate that the compound is a good candidate of nonlinear optical materials. The calculated vibrational wavenumbers, absorption wavelengths and chemical shifts showed the best agreement with the experimental results. © 2012 Elsevier B.V. All rights reserved.
NMR, UV, FT-IR, FT-Raman spectra and molecular structure (monomeric and dimeric structures) investigation of nicotinic acid N-oxide: A combined experimental and theoretical study
(2012) Atac A.; Karabacak M.; Karaca C.; Kose E.
In this work, the experimental and theoretical UV, NMR, and vibrational features of nicotinic acid N-oxide (abbreviated as NANO, C 6H 5NO 3) were studied. The ultraviolet (UV) absorption spectrum of studied compound that dissolved in water was examined in the range of 200-800 nm. FT-IR and FT-Raman spectra in solid state were observed in the region 4000-400 cm -1 and 3500-50 cm -1, respectively. The 1H and 13C NMR spectra in DMSO were recorded. The geometrical parameters, energies and the spectroscopic properties of NANO were obtained for all four conformers from density functional theory (DFT) B3LYP/6-311++G(d,p) basis set calculations. There are four conformers, C n, n = 1-4 for this molecule. The computational results identified the most stable conformer of title molecule as the C1 form. 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 nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by using the gauge-invariant atomic orbital (GIAO) method. The electronic properties, such as excitation energies, absorption wavelengths, HOMO and LUMO energies, were performed by CIS approach. Finally the calculation results were applied to simulate infrared, Raman, and UV spectra of the title compound which show good agreement with observed spectra. © 2011 Elsevier B.V. All rights reserved.
FT-IR and FT-Raman, NMR and UV spectroscopic investigation and hybrid computational (HF and DFT) analysis on the molecular structure of mesitylene
(Elsevier B.V., 2013) Kose E.; Atac A.; Karabacak M.; Nagabalasubramanian P.B.; Asiri A.M.; Periandy S.
(Graph Presented) The spectroscopic properties of mesitylene were investigated by FT-IR, FT-Raman, UV, 1H and 13C NMR techniques. The geometrical parameters and energies have been obtained from density functional theory (DFT) B3LYP method and Hartree-Fock (HF) method with 6-311++G(d,p) and 6-311G(d,p) basis sets calculations. The geometry of the molecule was fully optimized, vibrational spectra were calculated and fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. Total and partial density of state (TDOS and PDOS) and also overlap population density of state (OPDOS) diagrams analysis were presented. 13C and 1H NMR chemical shifts were calculated by using the gauge-invariant atomic orbital (GIAO) method. The electronic properties, such as excitation energies, oscillator strength, wavelengths, HOMO and LUMO energies, were performed by time-dependent density functional theory (TD-DFT) results complements with the experimental findings. The results of the calculations were applied to simulate spectra of the title compound, which show excellent agreement with observed spectra. Besides, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) and thermodynamic properties were performed. Reduced density gradient (RDG) of the mesitylene was also given to investigate interactions of the molecule. © 2013 Elsevier B.V. All rights reserved.
Determination of structural and vibrational spectroscopic features of neutral and anion forms of dinicotinic acid by using NMR, infrared and Raman experimental methods combined with DFT and HF
(Elsevier B.V., 2013) Kose E.; Bardak F.; Atac A.; Karabacak M.; Cipiloglu M.A.
In this study; the experimental (NMR, infrared and Raman) and theoretical (HF and DFT) analysis of dini-cotinic acid were presented. 1H and 13C NMR spectra were recorded in DMSO solution and chemical shifts were calculated by using the gauge-invariant atomic orbital (GiAO) method. The vibrational spectra of dinicotinic acid were recorded by FT-Raman and FT-iR spectra in the range of 4000-10 cm1 and 4000-400 cm 1, respectively. To determine the most stable neutral conformer of molecule, the selected torsion angle was changed every 10° and molecular energy profile was calculated from 0° to 360°. The geometrical parameters and energies were obtained for all conformers form from density functional theory (DFT/B3LYP) and HF with 6-311++G(d, p) basis set calculations. However, the results of the most stable neutral and two anion forms (anion1 and anion2 forms) of dinicotinic acid are reported here. The complete assignments were performed on the basis of the total energy distribution (TED) of the vibrational wavenumbers, calculated with scaled quantum mechanics (SQM) method and PQS program. © 2013 Elsevier B.V. All rights reserved.
Experimental (FT-IR, FT-Raman, UV-Vis, 1H and 13C NMR) and computational (density functional theory) studies on 3-bromophenylboronic acid
(Elsevier, 2014) Karabacak M.; Kose E.; Atac A.; Sas E.B.; Asiri A.M.; Kurt M.
Structurally, boronic acids are trivalent boron-containing organic compounds that possess one alkyl substituent (i.e., C-Br bond) and two hydroxyl groups to fill the remaining valences on the boron atom. We studied 3-bromophenylboronic acid (3BrPBA); a derivative of boronic acid. This study includes the experimental (FT-IR, FT-Raman, 1H and 13C NMR, UV-Vis) techniques and theoretical (DFT-density functional theory) calculations. The experimental data are recorded, FT-IR (4000-400 cm-1) and FT-Raman spectra (3500-10 cm-1) in the solid phase. 1H and 13C NMR spectra are recorded in DMSO solution. UV-Vis spectrum is recorded in the range of 200-400 nm for each solution (in ethanol and water). The theoretical calculations are computed DFT/B3LYP/6-311++G(d,p) basis set. The optimum geometry is also obtained from inside for possible four conformers using according to position of hydrogen atoms after the scan coordinate of these structures. The fundamental vibrations are assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and parallel quantum solutions (PQS) program. 1H and 13C NMR chemical shifts are racked on by using the gauge-invariant atomic orbital (GIAO) method. The time-dependent density functional theory (TD-DFT) is used to find HOMO and LUMO energies, excitation energies, oscillator strengths. The density of state of the studied molecule is investigated as total and partial density of state (TDOS and PDOS) and overlap population density of state (OPDOS or COOP) diagrams have been presented. Besides, frontier molecular orbitals (FMOs), molecular electrostatic potential surface (MEPs) and thermodynamic properties are performed. At the end of this work, the results are ensured beneficial for the literature contribution. © 2014 Elsevier B.V. All rights reserved.
Monomeric and dimeric structures analysis and spectroscopic characterization of 3,5-difluorophenylboronic acid with experimental (FT-IR, FT-Raman, 1H and 13C NMR, UV) techniques and quantum chemical calculations
(2014) Karabacak M.; Kose E.; Atac A.; Asiri A.M.; Kurt M.
The spectroscopic properties of 3,5-difluorophenylboronic acid (3,5-DFPBA, C6H3F2B(OH)2) were investigated by FT-IR, FT-Raman UV-Vis, 1H and 13C NMR spectroscopic techniques. FT-IR (4000-400 cm-1) and FT-Raman spectra (3500-10 cm-1) in the solid phase and 1H and 13C NMR spectra in DMSO solution were recorded. The UV spectra that dissolved in ethanol and water were recorded in the range of 200-400 nm for each solution. The structural and spectroscopic data of the molecule have been obtained for possible three conformers from DFT (B3LYP) with 6-311++G(d,p) basis set calculations. The geometry of the molecule was fully optimized, vibrational spectra were calculated and fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. Hydrogen-bonded dimer of title molecule, optimized by counterpoise correction, was also studied B3LYP at the 6-311++G(d,p) level and the effects of molecular association through O-Ha'O hydrogen bonding have been discussed. 1H and 13C NMR chemical shifts were calculated by using the gauge-invariant atomic orbital (GIAO) method. The electronic properties, such as excitation energies, oscillator strength, wavelengths, HOMO and LUMO energies, were performed by time-dependent density functional theory (TD-DFT) results complements with the experimental findings. Total and partial density of state (TDOS and PDOS) and also overlap population density of state (OPDOS) diagrams analysis were presented. The effects due to the substitutions of boric acid group and halogen were investigated. The results of the calculations were applied to simulate spectra of the title compound, which show excellent agreement with observed spectra. Besides, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP), nonlinear optical properties (NLO) and thermodynamic features were performed. © 2013 Elsevier B.V. All rights reserved.
The spectroscopic and quantum chemical studies of 3,4-difluoroaniline
(Elsevier, 2015) Kose E.; Karabacak M.; Atac A.
Spectroscopic and structural investigations of 3,4-difluoroaniline molecule are presented by using experimental (FT-IR, FT-Raman, 1H and 13C NMR, and UV-Vis) techniques and theoretical (DFT approach) calculations. FT-IR and FT-Raman spectra of 3,4-difluoroaniline molecule are recorded in the region 4000-400 cm-1 and 3500-10 cm-1 in the liquid phase, respectively. The NMR chemical shifts (1H and 13C) are recorded in chloroform-d solution. The UV absorption spectra of 3,4-difluoroaniline dissolved in ethanol and water are recorded in the range of 200-400 nm. Experimental results are supported with the following theoretical calculations; the optimized geometry and vibrational (FT-IR and FT-Raman) spectra are carried out by DFT (B3LYP)/6-311++G(d,p) basis set calculations. The nuclear magnetic resonance spectra (1H and 13C NMR) are obtained by using the gauge-invariant atomic orbital method. Moreover, electronic characteristics, such as HOMO and LUMO energies, density of state diagrams, and molecular electrostatic potential surface are investigated. Nonlinear optical properties and thermodynamic features are also outlined theoretically. An excellent correlation of theoretical and experimental results provides a detailed description of the structural and physicochemical properties of the molecule. Thus, this work leads to a deep understanding of the characteristics of di-substituted aniline derivatives. © 2015 Elsevier B.V.All rights reserved.
FT-IR, FT-Raman, NMR and UV-Vis spectra and DFT calculations of 5-bromo-2-ethoxyphenylboronic acid (monomer and dimer structures)
(Elsevier B.V., 2015) Sas E.B.; Kose E.; Kurt M.; Karabacak M.
In this study, the Fourier Transform Infrared (FT-IR) and Fourier Transform Raman (FT-Raman) spectra of 5-bromo-2-ethoxyphenylboronic acid (5Br2EPBA) are recorded in the solid phase in the region 4000-400 cm-1 and 3500-10 cm-1, respectively. The 1H, 13C and DEPT nuclear magnetic resonance (NMR) spectra are recorded in DMSO solution. The UV-Vis absorption spectrum of 5Br2EPBA is saved in the range of 200-400 nm in ethanol and water. The following theoretical calculations for monomeric and dimeric structures are supported by experimental results. The molecular geometry and vibrational frequencies in the ground state are calculated by using DFT methods with 6-31G(d,p) and 6-311G(d,p) basis sets. There are four conformers for the present molecule. The computational results diagnose the most stable conformer of 5Br2EPBA as Trans-Cis (TC) form. The complete assignments are performed on the basis of the total energy distribution (TED) of vibrational modes, calculated with scaled quantum mechanics (SQM) method in parallel quantum solutions (PQS) program. The 1H and 13C NMR chemical shifts of 5Br2EPBA molecule are calculated by using the Gauge Invariant Atomic Orbital (GIAO) method in DMSO and gas phase for monomer and dimer structures of the most stable conformer. Moreover, electronic properties, such as the HOMO and LUMO energies (by TD-DFT and CIS methods) and molecular electrostatic potential surface (MEPs) are investigated. Stability of the molecule arising from hyper-conjugative interactions, charge delocalization is analyzed using natural bond orbital (NBO) analysis. Nonlinear optical (NLO) properties and thermodynamic features are presented. All calculated results are compared with the experimental data of the title molecule. The correlation of theoretical and experimental results provides a detailed description of the structural and physicochemical properties of the title molecule. © 2014 Elsevier B.V. All rights reserved.
DFT calculations and experimental FT-IR, FT-Raman, NMR, UV-Vis spectral studies of 3-fluorophenylboronic acid
(Elsevier, 2015) Karabacak M.; Kose E.; Sas E.B.; Kurt M.; Asiri A.M.; Atac A.
The spectroscopic (FT-IR, FT-Raman, 1H and 13C NMR, UV-Vis), structural, electronic and thermodynamical properties of 3-fluorophenylboronic acid (C6H4FB(OH)2), 3FPBA) were submitted by using both experimental techniques and theoretical methods (quantum chemical calculations) in this work. The experimental infrared and Raman spectra were obtained in the region 4000-400 cm-1 and 3500-10 cm-1, respectively. The equilibrium geometry and vibrational spectra were calculated by using DFT (B3LYP) with 6-311++G(d,p) basis set. The vibrational wavenumbers were also corrected with scale factor to take better results for the calculated data. The total energy distributions (TED) of the vibrational modes were performed for the assignments of the title molecule by using scaled quantum mechanics (SQM) method. The NMR chemical shifts (1H and 13C) were recorded in DMSO solution. The 1H and 13C NMR spectra were computed by using the gauge-invariant atomic orbital (GIAO) method, showing a good agreement with the experimental ones. The last one UV-Vis absorption spectra were analyzed in two solvents (ethanol and water), saved in the range of 200-400 nm. In addition these, HOMO and LUMO energies, the excitation energies, density of states (DOS) diagrams, thermodynamical properties and molecular electrostatic potential surface (MEPs) were presented. Nonlinear optical (NLO) properties and thermodynamic features were performed. The experimental results are combined with the theoretical calculations using DFT calculations to fortification of the paper. At the end of this work, the results were proved our paper had been indispensable for the literature backing. © 2014 Elsevier B.V. All rights reserved.
Determination of drying characteristics and quality properties of eggplant in different drying conditions
(Chiriotti Editori, 2015) Urun G.B.; Yaman U.R.; Kose E.
Drying is the most traditional process used for preserving eggplant a long time. The aim of this study was to determining drying characteristics and quality properties of eggplant dried by sun drying, hot air convective drying and infrared assisted convective drying. Convective drying and infrared assisted convective were carried out in a convective dryer at three different temperatures (40°, 50°, 60°C) and air velocity at 5 m/s. The increasing of temperatures during the drying of eggplant led to a significant reduction of the drying time. However loss of nutrition was observed in eggplant samples dried at higher temperature. The biggest change in colour parameters was observed in samples dried with sun drying. So it was thought that sun drying had a negative effect on quality properties of eggplant samples.
Conformational, electronic, and spectroscopic characterization of isophthalic acid (monomer and dimer structures) experimentally and by DFT
(Elsevier B.V., 2016) Bardak F.; Karaca C.; Bilgili S.; Atac A.; Mavis T.; Asiri A.M.; Karabacak M.; Kose E.
Isophthalic acid (C6H4(CO2H)2) is a noteworthy organic compound widely used in coating and synthesis of resins and the production of commercially important polymers such as drink plastic bottles. The effects of isophthalic acid (IPA) on human health, toxicology, and biodegradability are the main focus of many researchers. Because structural and spectroscopic investigation of molecules provides a deep understanding of interactional behaviors of compounds, this study stands for exploring those features. Therefore, the spectroscopic, structural, electronic, and thermodynamical properties of IPA were thoroughly studied in this work experimentally using UV-Vis, 1H and 13C NMR, FT-IR, FT-Raman and theoretically via DFT and TD-DFT calculations. The UV-Vis absorption spectrum in water was taken in the region 200-400 nm. The NMR chemical shifts (1H and 13C) were recorded in DMSO solution. The infrared and Raman spectra of the solid IPA were recorded in the range of 4000-400 cm- 1 and 3500-50 cm- 1, respectively. DFT and TD-DFT calculations were performed at the level of B3LYP/6-311++G(d,p) in determination of geometrical structure, electronic structure analysis and normal mode. The 13C and 1H nuclear magnetic resonance (NMR) spectra were estimated by using the gauge-invariant atomic orbital (GIAO) method. The scaled quantum mechanics (SQM) method was used to determine the total energy distribution (TED) to assign the vibrational modes accurately. Weak interactions such as hydrogen bonding and Van der Walls were analyzed via reduced density gradient (RDG) analysis in monomeric and dimeric forms. Furthermore, the excitation energies, density of state (DOS) diagram, thermodynamical properties, molecular electro-static potential (MEP), and nonlinear optical (NLO) properties were obtained. © 2016 Elsevier B.V. All rights reserved.
Spectral investigations of 2,5-difluoroaniline by using mass, electronic absorption, NMR, and vibrational spectra
(Elsevier B.V., 2016) Kose E.; Karabacak M.; Bardak F.; Atac A.
One of the most significant aromatic amines is aniline, a primary aromatic amine replacing one hydrogen atom of a benzene molecule with an amino group (NH2). This study reports experimental and theoretical investigation of 2,5-difluoroaniline molecule (2,5-DFA) by using mass, ultraviolet-visible (UV-vis), 1H and 13C nuclear magnetic resonance (NMR), Fourier transform infrared and Raman (FT-IR and FT-Raman) spectra, and supported with theoretical calculations. Mass spectrum (MS) of 2,5-DFA is presented with their stabilities. The UV-vis spectra of the molecule are recorded in the range of 190-400 nm in water and ethanol solvents. The 1H and 13C NMR chemical shifts are recorded in CDCl3 solution. The vibrational spectra are recorded in the region 4000-400 cm-1 (FT-IR) and 4000-10 cm-1 (FT-Raman), respectively. Theoretical studies are underpinned the experimental results as described below; 2,5-DFA molecule is optimized by using B3LYP/6-311++G(d,p) basis set. The mass spectrum is evaluated and possible fragmentations are proposed based on the stable structure. The electronic properties, such as excitation energies, oscillator strengths, wavelengths, frontier molecular orbitals (FMO), HOMO and LUMO energies, are determined by time-dependent density functional theory (TD-DFT). The electrostatic potential surface (ESPs), density of state (DOS) diagrams are also prepared and evaluated. In addition to these, reduced density gradient (RDG) analysis is performed, and thermodynamic features are carried out theoretically. The NMR spectra (1H and 13C) are calculated by using the gauge-invariant atomic orbital (GIAO) method. The vibrational spectra of 2,5-DFA molecule are obtained by using DFT/B3LYP method with 6-311++G(d,p) basis set. Fundamental vibrations are assigned based on the potential energy distribution (PED) of the vibrational modes. The nonlinear optical properties (NLO) are also investigated. The theoretical and experimental results give a detailed description of the structural and physicochemical properties of the title molecule and contribute to understanding of the nature of di-substituted aniline derivatives. © 2016 Elsevier B.V.
Comparison of physicochemical and functional properties of domestic and commercial tarhana in Turkey
(National Centre for Agrarian Sciences, 2016) Cagindi O.; Aksoylu Z.; Savlak N.Y.; Kose E.
Tarhana, cereal-based fermented product, is made domestically or commercially with different ingredients and recipes. Nutritional properties depend on ingredients and their ratios in recipe. In this research, some quality properties of 22 domestic and 14 commercial samples collected from 25 different locations of Turkey were analysed. Moisture, ash, salt, protein, crude fat, acidity degree, pH, aw, viscosity, L* (lightness), a* (redness), b* (yellowness) values, total antioxidant activity (AOA) and total phenolic content of domestic and commercial samples were determined and compared. Domestic samples had higher fat content and varied in salt content, while commercial samples had more uniform physicochemical properties. © 2016, National Centre for Agrarian Sciences. All rights reserved.
The spectroscopic (FT-IR, FT-Raman, dispersive Raman and NMR) study of ethyl-6-chloronicotinate molecule by combined density functional theory
(Elsevier, 2016) Karabacak M.; Calisir Z.; Kurt M.; Kose E.; Atac A.
In this study, ethyl-6-chloronicotinate (E-6-ClN) molecule is recorded in the region 4000-400 cm- 1 and 3500-100 cm- 1 (FT-IR, FT-Raman and dispersive Raman, respectively) in the solid phase. 1H and 13C nuclear magnetic resonance (NMR) spectra are recorded in DMSO solution. The structural and spectroscopic data of the molecule are obtained for two possible isomers (S1 and S2) from DFT (B3LYP) with 6-311++G(d,p) basis set calculations. The geometry of the molecule is fully optimized, vibrational spectra are calculated and fundamental vibrations are assigned on the basis of the potential energy distribution (PED) of the vibrational modes. 1H and 13C NMR chemical shifts are calculated by using the gauge-invariant atomic orbital (GIAO) method. The electronic properties, such as excitation energies, oscillator strengths, wavelengths, HOMO and LUMO energies, are performed by time-dependent density functional theory (TD-DFT). Total and partial density of state and overlap population density of state diagrams analysis are presented for E-6-ClN molecule. Furthermore, frontier molecular orbitals (FMO), molecular electrostatic potential, and thermodynamic features are performed. In addition to these, reduced density gradient of the molecule is performed and discussed. As a conclusion, the calculated results are compared with the experimental spectra of the title compound. The results of the calculations are applied to simulate the vibrational spectra of the molecule, which show excellent agreement with the observed ones. The theoretical and tentative results will give us a detailed description of the structural and physicochemical properties of the molecule. Natural bond orbital analysis is done to have more information stability of the molecule arising from charge delocalization, and to reveal the information regarding charge transfer within the molecules. © 2015 Elsevier B.V. All rights reserved.
The structural and spectroscopic investigation of 2-chloro-3-methylquinoline by DFT method and UV–Vis, NMR and vibrational spectral techniques combined with molecular docking analysis
(Elsevier B.V., 2018) Kose E.; Atac A.; Bardak F.
This study comprises the structural and spectroscopic evaluation of a quinoline derivative, 2-chloro-3-methylquinoline (2Cl3MQ), via UV–Vis, 1H and 13C NMR, FT-IR and FT-Raman techniques experimentally, theoretically with DFT and TD-DFT quantum chemical calculations at B3LYP/6–311++G (d, p) level of theory, and investigation of the in silico pharmaceutical potent of 2Cl3MQ in comparison to 2ClnMQ (n = 3,4,7,8,9,10) substituted quinolines. The experimental measurements were recorded as follows; UV–vis spectra were obtained in the range of 200–400 nm in the water and ethanol solvents. 1H and 13C NMR spectra were recorded in CDCl3. Vibrational spectra were obtained in the region of 4000–400 cm−1 and 3500–10 cm−1 for FT-IR and FT-Raman spectra, respectively. Structural and spectroscopic features obtained through theoretical evaluations include: electrostatic features, atomic charges and molecular electrostatic potential surface, the frontier molecular orbital characteristics, the density of states and their overlapping nature, the electronic transition properties, thermodynamical and nonlinear optical characteristics, and predicted UV–Vis, 1H and 13C NMR, FT-IR and FT-Raman spectra. Ligand-enzyme interactions of 2ClnMQ (n = 3,4,7,8,9,10) substituted quinolines with Malate Synthase from Mycobacterium Tuberculosis (MtbMS) were investigated via molecular docking. The role of position of methyl substitution on the inhibitor character of the ligands was discussed on the basis of noncovalent interaction profiles. © 2018 Elsevier B.V.
The investigation of fluorine substitution in difluoroanilines with focus on 2,6-difluoroaniline by spectroscopic methods, density functional theory approach, and molecular docking
(Elsevier B.V., 2019) Kose E.; Bardak F.; Atac A.
In this study, the spectroscopic features and reactive nature of difluoroanilines, with special attention on 2,6-difluoroaniline (2,6-DFA), are explored thoroughly to gain insight into the effect of fluorine substitution in aniline derivatives. The quantum chemically obtained spectral properties including Fourier transform infrared, Raman, ultraviolet, and 1H and 13C nuclear magnetic resonance spectra were obtained by using Density Functional Theory (DFT) calculations at B3LYP/6-311++G(d,p) level of theory, and given along with the ones measured experimentally. The reactivity characteristics such as Fukui descriptor, electrostatic potential, and electronegativity were defined based on electron density generated theoretically. The position of fluorine substitution does not significantly alter the amide group reactivity making all difluoroanilines compatible to each other in terms of the reactivity. The time-dependent DFT was used to calculate the electronic properties such as excitation energies, maximum wavelengths, oscillator strengths, and molecular orbitals energies, and given along with the density of state diagrams. The intramolecular interactions were mapped by reduced density gradient method to reveal possible fluorine influence on the amide group and its reactivity, and the strongest van der Waals interactions in 2,6-DFA were observed. Besides, the thermodynamic and nonlinear optical properties of the title molecule were also investigated. The 2,6-DFA molecule seems to be appealing for multidisciplinary studies about the relevant nonlinear optical properties. To explore the binding capability of 2,6-DFA and see the influence of fluorine substitution in difluoroanilines, molecular docking was performed on a model enzyme structure of T4 lysozyme. Ligand-enzyme binding energies of 2,6-DFA is nearly the same with that of 2,5 DFA and 3,5 DFA at the same binding site which differs from the remaining derivatives. © 2019 Elsevier B.V.

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