Browsing by Author "Bardak F."
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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 Infrared and Raman study of some isonicotinic acid metal(II) halide and tetracyanonickelate complexes(2009) Bardak F.; Atac A.; Kurt M.In this study the M(IN)2Ni(CN)4 [where M: Co, Ni, and Cd, and IN: isonicotinic acid, abbreviated to M-Ni-IN] tetracyanonickelate and some metal halide complexes with the following stoichiometries: M(IN)6X2 (M: Co; X: Cl and Br, and M: Ni; X: Cl, Br and I) and Hg(IN)X2 (X: Cl, Br, and I) were synthesized for the first time. Certain chemical formulas were determined using elemental analysis results. The FT-IR and Raman spectra of the metal halide complexes were reported in the 4000-0 cm-1 region. The FT-IR spectra of tetracyanonickelate complexes were also reported in the 4000-400 cm-1 region. Vibrational assignments were given for all the observed bands. For a given series of isomorphous complexes, the sum of the difference between the values of the vibrational modes of the free isonicotinic acid and coordinated ligand was found to increase in the order of the second ionization potentials of metals. The frequency shifts were also found to be depending on the halogen. 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 atom. © 2008 Elsevier B.V. All rights reserved.Item 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.Item Heterogeneous dynamics in ionic liquids at the glass transition: Fluorescence recovery after photobleaching measurements of probe rotational motion from Tg - 6 K to Tg + 4 K(Elsevier B.V., 2015) Bardak F.; Rajian J.R.; Son P.; Quitevis E.L.The rotational dynamics of tetracene and rubrene in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([C4C1im][PF6]) at the glass transition (Tg = 196 K), from Tg - 6 K to Tg + 4 K, were measured using the technique of fluorescence recovery after photobleaching. The rotational anisotropy decays of these probes in [C4C1im][PF6] were found to be non-exponential and well fit by the Kohlrausch-Williams-Watts (KWW) function with the stretching parameter βKWW equal to 0.70 ± 0.03 for tetracene and 0.88 ± 0.04 for rubrene in the temperature range of the measurements. The rotational correlation time τc at Tg is equal to 19 ± 1 s for the smaller probe tetracene and 180 ± 40 s for the larger probe rubrene. Below Tg, τc shows a slight decoupling from the extrapolation of fits of the Vogel-Fulcher-Tammann equation to the viscosity η. This decoupling is characterized by a fractional Debye-Stokes-Einstein relation, τc ∝ ηξ/T, with ξ equal to 0.78 ± 0.02 for rubrene and 0.85 ± 0.01 for tetracene. The dependence of βKWW on probe size is consistent with the dynamics in [C4C1im][PF6] being heterogeneous and is rationalized in terms of the time scale of the probe rotational motion compared to the domain exchange time. © 2014 Elsevier B.V. All rights reserved.Item 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.Item 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.Item Combined experimental and theoretical studies on the molecular structures, spectroscopy, and inhibitor activity of 3-(2-thienyl)acrylic acid through AIM, NBO,FT-IR, FT-Raman, UV and HOMO-LUMO analyses, and molecular docking(Elsevier B.V., 2017) Issaoui N.; Ghalla H.; Bardak F.; Karabacak M.; Aouled Dlala N.; Flakus H.T.; Oujia B.In this work, the molecular structures and vibrational spectral analyses of 3-(2-Theinyl)acrylic acid (3-2TAA) monomer and dimer structures have been reported by using density functional theory calculations at B3LYP/6-311++G(d,p) level of theory. The complete assignments of the fundamental vibrational modes were obtained using potential energy distribution. Intermolecular interactions were analyzed by orbital NBO and topological AIM approaches. The electronic properties have been carried out using TD-DFT approach. Great agreements between experimental and theoretical values were achieved throughout the analysis of structural parameters and spectroscopic features. Inhibitor characteristics on human monoamine oxidase B (MAOB) enzyme of two determined stable conformers of 3-2TAA (β and γ) along with four selective inhibitors, namely safinamide, a coumarin analogue, farnesol, and phenyethylhydrazine were investigated via molecular docking. Moreover, molecular electrostatic potential (MEP) and temperature dependency of thermodynamic functions have been reported. © 2016 Elsevier B.V.Item Comparative study of the intermolecular dynamics of imidazolium-based ionic liquids with linear and branched alkyl chains: OHD-RIKES measurements(Royal Society of Chemistry, 2017) Xue L.; Bardak F.; Tamas G.; Quitevis E.L.This article describes a comparative study of the low-frequency (0-450 cm-1) Kerr spectra of the branched 1-(iso-alkyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([(N - 2)mCN-1C1im][NTf2] with N = 3-7) ionic liquids (ILs) and that of the linear 1-(n-alkyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([CNC1im][NTf2] with N = 2-7) ILs. The spectra were obtained by use of femtosecond optical heterodyne-detected Raman-induced Kerr effect spectroscopy (OHD-RIKES). The intermolecular spectrum of a branched IL is similar to that of a linear IL that is of the same alkyl chain length rather than of the same number of carbon atoms in the alkyl chain. This similarity and the lack of a correlation of the first spectral moments and widths of the intermolecular spectra with chain length is mainly attributed to the increase in the dispersion contribution to the total molar cohesive energy being compensated by stretching of the ionic network due to the increasing size of the nonpolar domains, which is dependent only on the length of the alkyl chain. © the Owner Societies 2017.Item Synthesis, structural and spectroscopic features, and investigation of bioactive nature of a novel organic-inorganic hybrid material 1H-1,2,4-triazole-4-ium trioxonitrate(Elsevier B.V., 2017) Gatfaoui S.; Issaoui N.; Mezni A.; Bardak F.; Roisnel T.; Atac A.; Marouani H.The novel inorganic-organic hybrid material 1H-1,2,4-triazole-4-ium trioxonitrate (TAN) have been elaborated and crystallized to the monoclinic system with space group P21/c and the lattice parameters obtained are a = 8.8517(15) Å, b = 8.3791(15) Å, c = 7.1060(11) Å, β = 103.776(7)°, V = 511.89(15) Å3 and Z = 4. In order to enhance (TAN) on the applied plan, biophysicochemical characterization of the title compound have been obtained with experimentally and theoretically. The crystal structure exposed substantial hydrogen bonding stuck between the protonated 1,2,4-triazole ring and the nitrate forming thus sheets parallel to the plans (−1 0 1). The three-dimensional supramolecular network is formed through the π … π interactions involving heterocyclic rings in these sheets. Assessment of intermolecular contacts in the crystal arrangement was quantified by Hirshfeld surface analysis and interactions were analyzed by orbital NBO and topological AIM approaches. This compound was also investigated by means of infrared spectroscopy, electrical conductivity, thermal analysis TG-DTA, and DSC. Moreover, the antioxidant properties of TAN were determined via the DPPH radical scavenging, the ABTS radical scavenging, hydroxyl radical scavenging, and ferric reducing power (FRP). Obtained results confirm the functionality of antioxidant potency of TAN. The molecular structure and vibrational spectral analysis of TAN have been reported by using density functional theory calculations at B3LYP/6-311++G(d,p) level of theory. Molecular docking behaviors of TAN along with well-known triazole antifungal agents (fluconazole, itraconazole, posaconazole, and voriconazole) with saccharomyces cerevisiae CYP51 (Lanosterol 14-alpha demethylase) were investigated. The potent of TAN as an inhibitor was discussed on the basis of noncovalent interaction profile. Furthermore, protonic conduction of this compound has been intentional in the temperature range of 295–373 K. © 2017 Elsevier B.V.Item Experimental FTIR and FT-Raman and theoretical studies on the molecular structures of monomer and dimer of 3-thiopheneacrylic acid(Elsevier B.V., 2017) Issaoui N.; Ghalla H.; Brandán S.A.; Bardak F.; Flakus H.T.; Atac A.; Oujia B.This work presents an experimental and theoretical investigation on the properties of 3-thiopheneacrylic acid (3TAA) by using the FT-Raman and FT-IR spectra in the solid state. The structural, electronic, topological and vibrational properties of 3TAA were theoretically studied by using the hybrid B3LYP method with the 6-311++G (d,p) basis set. The complete assignments of the bands observed in both spectra were performed taking into account the presence of both monomer and dimer species of the acid. Two bands observed at 1682 and 1625 cm−1 attributed to the C[dbnd]C and C[dbnd]O stretching modes, respectively support the presence of the dimeric species in the solid phase. The percentages of intermolecular interactions are analyzed by Fingerprint plots of Hirshfeld surface. The natural bond orbital (NBO), atoms in molecules (AIM), frontier molecular orbitals (FMOs) and molecular electrostatic potential surface (MEPs) calculations were employed to determine the structural properties while the chemical selectivity or reactivity sites were revealed by using the Fukui functions. The GIAO and time-dependent density functional theory (TD-DFT) methods were used to predict the 1H and 13C NMR and electronic spectra of the acid. The diagrams of the density of state of that acid have been also presented. Finally, reasonable correlations between experimental and theoretical vibrational spectra were found. Effect of positioning and orientation of the acrylic group on the inhibitor characteristics on human MAOB enzyme of stable conformers of 3TAA is investigated in comparison with that of 3-2TAA and four selective inhibitors via molecular docking. © 2017 Elsevier B.V.Item 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.Item Intermolecular interactions and molecular docking investigations on 4-methoxybenzaldehyde(Elsevier B.V., 2018) Ghalla H.; Issaoui N.; Bardak F.; Atac A.In this work, a structural and electronic properties of 4-methoxybenzaldehyde (4MBA) have been presented. The density functional theory (DFT) along with B3LYP hybrid functional is employed. The optimized structure was found to be in well consistent with the X-ray diffraction geometry. The 4MBA crystal is stabilized by C-H⋯O intermolecular interactions along with π⋯π interactions. Various intermolecular interactions involved in 4MBA crystal have been analyzed deeply through topological atom-in-molecules (AIM) analysis and noncovalent interactions (NCI) method. Besides, Hirshfeld surface (HS) analysis and fingerprint plots are performed to determine the contribution of intermolecular contacts in 4MBA crystal packing. The electronic properties of the title compound have been investigated. Nonlinear optic (NLO) properties of 4MBA have been interpreted through the calculated first hyperpolarizability value. 4-substituted benzaldehydes, including 4MBA, are known with their competitive inhibitory activity on Tyrosinase, which also known as polyphenol oxidase (PPO). This enzyme is a rate limiting enzyme that controls the production of melamine and brown coloring of foods. Thus, molecular docking behaviors of 4MBA are presented in comparison with that of benzaldehyde (BA), 4-ethylBA, 4-tertbutylBA, 4-isoprophylBA, 4-propoxyBA, 4-butoxyBA, and Hexylresorcinol on four selected PPOs from sweet potato, grape, and mushroom. © 2018 Elsevier B.V.Item Experimental and DFT analysis of structural and spectroscopic features of nitroterephthalic acid, and computational insights into its molecular interactions with hER-α via molecular docking(Elsevier B.V., 2019) Bardak F.It has become clear that the exposure to the ubiquitous xenoestrogens are the first line causatives for human breast cancer. Besides, terephthalic acid (TPA), the major chemical constituent in the synthesis of polyethylene terephthalate (PET), also shown to have carcinogenic effects. Nitroterephthalic acid (NTPA) modified PET or polyethylene glycol (PEG) polymers are suggested to have lower risk, however little known about the reactive nature of NTPA especially in terms of its interactions with estrogen receptors. Therefore, this study focuses on the investigation of structural and spectroscopic features of NTPA through experimental and theoretical methods, and the exploration of interactions with human estrogen receptor alpha (hER-α) in comparison with that of benzoic acid (BA), phthalic acid (PA), and terephthalic acid (TPA) by using molecular docking methodology. Essential quantum descriptors obtained for NTPA include electrostatic potential surface, electrophilicity and nucleophilicity from Fukui analysis, aromaticity indexes from nuclear independent chemical shift (NICS) analysis, and electronic properties like band gap and ionization potentials from population analysis. Infrared, Raman, and UV spectra are presented both experimentally and via ab initio density functional theory calculations obtained at the B3LYP 6-311++G(d,p) level of theory. Ligand-enzyme interactions were discussed within a dependency on the structural variations in four ligands in docking analysis. NTPA was found to behave like phthalic acid and highly rich in terms of conformations in monomeric and dimeric forms. © 2018 Elsevier B.V.Item Effect of the external electric field on the electronic structure, spectroscopic features, NLO properties, and interionic interactions in ionic liquids: A DFT approach(Elsevier B.V., 2019) Bardak C.; Atac A.; Bardak F.Ionic liquid (IL)s are a unique group of chemicals with extraordinary physical and chemical properties. Due to the advantage of the tunability of their features by varying the ion compositions and either IL/IL or IL/conventional solvent mixing ratios, uncountable functions of them have been discovered. In the field of electrochemistry and energy applications, the function of ILs under external field should also be understood well. The most fundamental way of gaining insight into the function of a substance is to study the structure. Therefore, this work focuses on the investigation of structural variations of an exemplary IL, 1-hexyl 3-methylimidazolium chloride (HmimCl), under external electric field (EEF) via ab initio quantum chemistry calculations. Field dependent geometry analysis show that the interionic bond and the molecular conformation can be modulated by the strength and the direction of the applied field, and the disassociation occurs at ~0.7 V/Å level. Mulliken, atomic polar tensor, and natural bond orbital charges were obtained within field dependency and their correlation was examined. Charge displacement curves were constructed to visualize the field inducement on the charge transfer. Interionic interactions were profiled as hydrogen, van der Walls, and steric effect by using reduced density gradient analysis and the breaking of the single hydrogen bond was determined to occur at ~0.6 V/Å level. The vibrational spectra (IR and Raman) were simulated and the critical peaks that are affected by the field inducement were interpreted. The analysis of the field dependent Nonlinear Optical (NLO) properties shows that the only important component is in the field direction for the field intensity >0.2 V/Å. Electronic transition properties determined via TD-DFT calculations with B3LYP/6-311G** level of theory indicate that the UV–Vis spectrum and underlying transitions are depended on the direction of the field, and experience a bathochromic shift with increasing inducement showing that the IL becomes more susceptible to excitation. © 2018 Elsevier B.V.Item 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.Item Synthesis and physic-chemical properties of a novel chromate compound with potential biological applications, bis(2-phenylethylammonium) chromate(VI)(Elsevier B.V., 2019) Trabelsi S.; Issaoui N.; Brandán S.A.; Bardak F.; Roisnel T.; Atac A.; Marouani H.The structure of bis(2-phenylethylammonium) chromate (VI) (2phCr) was determined from X-ray diffraction data. The compound crystallizes in the monoclinic system (space group C2/c) with the lattice parameters: a = 38.136 (2) Å b = 11.2334 (6) Å c = 8.1643 (4) Å; β = 98.480 (2) V = 3459.3 (3) Å 3 and Z = 8. The structure was solved from 3358 independent reflections with R = 0.034 and Rw = 0.1089. The structure consists of discrete anions (CrO 4 2− ) stacked in layers parallel to (b, c) plane at x = 1/4 and 3/4. These anions are connected to the 2-phenylethylammonium cations through N–H⋯O and C–H⋯O hydrogen bonds, forming a two-dimensional arrangement. Crystal structure and spectroscopic studies are reported for the 2phCr. In addition, Hirshfeld surfaces and two-dimensional fingerprint plots estimate the intermolecular interactions accountable for the generation of crystal packing. Furthermore, the title compound was screened for antibacterial activities against five pathogenic strains namely: Escherichia coli ATCC 8739, Salmonella typhimurium ATCC 14028, Staphylococus aureus ATCC 6538, Enterococcus feacium ATCC 19434 and Streptocoque B (Sreptococcus agalactiae) and antifungal activities against a clinical strain called Candida albicans ATCC 10231, corroborating significant activity. In silico investigation of bioactivity of 2phCr was performed via molecular docking analysis with four types of secreted aspartic proteinases (SAP, SAP1, SAP3, and SAP5) from Candida albicans to explore the antifungal properties in comparison to behavior of known antifungals used to treat Candida albicans, and with three types of β-ketoacyl acyl carrier protein synthase enzymes (KAS I (FabB), KAS II (FabF) and KAS III (FabH)) from Escherichia coli in comparison with that of aminothiazole, thilactomycin, and cerulerin antimicrobials. In addition, the complete assignments for 2phCr are reported considering monodentate coordination for the chromate group. © 2019 Elsevier B.V.Item Theoretical and experimental investigation of the spectroscopic features of and interionic interactions in 1-hexyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium tetrafluoroborate and 1-hexyl-3-methylimidazolium hexafluorophosphate ionic liquids(Elsevier B.V., 2020) Bilgili S.; Atac A.; Bardak F.In this work, the spectroscopic and electronic properties of three imidazolium-based ionic liquids (ILs) with 1-Hexyl-3-methylimidazolium cation and chloride, tetrafluoroborate, and hexafluorophosphate anions have been investigated theoretically and experimentally. The ground state electronic structure features such as molecular electrostatic potential, IR and Raman spectra, have been achieved through density functional theory (DFT) calculations at the B3LYP/6–311++G(d,p) level of theory in Gaussian 16. The resulting electron density has been analyzed to reveal intra- and interionic non-covalent interactions via atoms in molecules (AIM) approach and interpreted in terms of both the anion dependency and interaction type. The electronic transition characteristics have been carried out by time-dependent DFT calculations at the same level. The nuclear magnetic resonance shielding constants and chemical shifts have been computed by applying the DFT/gauge-including atomic orbitals (GIAO) method. The experimental measurements associated with the performed calculations include FT-IR and FT-Raman, UV–Vis, and 1H and 13C NMR spectra. The experimental spectroscopic signatures have been interpreted under the light of theoretical calculations. The effect of anion on the electronic structure and spectroscopic features are interpreted in accordance with the that of the density, viscosity, surface tension, refractive index, and the electrical conductivity results from previous works on the physicochemical properties of [Hmim][Cl], [Hmim][BF4], and [Hmim][PF6] ionic liquids. © 2020 Elsevier B.V.Item Structural, theoretical and third order nonlinear optical properties of (E)-N’-(4-chlorobenzylidene)-4-fluorobenzohydrazide monohydrate(Taylor and Francis Ltd., 2021) Latha N.; Barathi D.; Uthaya Kumar M.; Vennila K.N.; Vinitha G.; Mani R.; Louhi-Kultanen M.; Bardak F.; Atac A.; Kose E.The title compound (E)-N’-(4-chlorobenzylidene)-4-fluorobenzohydrazide monohydrate (CBFBH) is a novel hydrazone Schiff base compound, synthesized and characterized by FTIR, 1H and 13C NMR, UV-Vis and single crystal X-ray diffraction analyses. Quantum chemical computations were performed by Density Functional Theory (DFT) with B3LYP/6-311G (d,p) level to study the structural and spectral properties of the synthesized compound. Reliability of the crystal structure was visualized by Hirshfeld surface analysis. Third-order nonlinear optical polarization coefficient was calculated by Z-scan technique. © 2021 Taylor & Francis Group, LLC.