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Öğe Azo-methoxy-calix[4]arene complexes with metal cations for chemical sensor applications: Characterization, QTAIM analyses and dispersion-corrected DFT- computations(Pergamon-Elsevier Science Ltd, 2022) Gassoumi, B.; Echabaane, M.; Ben Mohamed, F. E.; Nouar, L.; Madi, F.; Karayel, Arzu; Ben Chaabane, R.In this work, the structures, quantum chemical descriptors, morphologic characterization of the azomethoxy-calix[4]arene were investigated. The analyses and interpretation of the theoretical and the experimental IR spectroscopy results for the corresponding compounds was performed. The complexation of the azo-methoxy-calix[4]arene with Zn2+, Hg2+, Cu2+, Co2+, Ni2+, Pb2+ and Cd2+ metal cations has been calculated by the dispersion corrected density functional theory (DFT-D3). The values of the interaction energies show that the specific molecule is more selective to the Cu2+ cation. The study of the reactivity parameters confirms that the azo-methoxy-calix[4]arene molecule is more reactive and sensitive to the Cu2+ cation than that Co2+ and Cd2+. In addition, the investigation of the electrophilic and nucleophilic sites has been studied by the molecular electrostatic potential (MEP) analysis. The Hirshfeld surface (HS) analysis of the azo-methoxy-calix[4]arene-Cu2+ interaction have been used to understand the Cu...hydrogen-bond donors formed between the cation and the specific compound. The Quantum Theory of Atoms in Molecules (QTAIM) via Non covalent Interaction (NCI) analysis was carried out to demonstrate the nature, the type and the strength of the interaction formed between the Cu2+ cation and the two symmetrical ligands and the cavity. Finally, the chemical sensor properties based on the Si/SiO2/Si3N4/Azo-methoxy-calix[4]arene for detection of Cu2+ cation were studied. Sensing performances are determined with a linear range from 10(-5.2) to 10(-2.2) M. The Si/SiO2/Si3N4/azo-methoxy-calix[4]arene structure is a promoter to have a good performance sensor. (C) 2021 Elsevier B.V. All rights reserved.Öğe Computational Insight into Conformational Rearrangement and Intramolecular-H Bond Analysis of Some Calix[4]Arenes Including Acryloyl Moiety(2019) Karayel, ArzuThe conformational analyses of Calix[4]arenes reveals four different stable structures (conformations); Cone, Partial Cone, 1,2-Alternate and 1,3-Alternate after employing a density functional theory (DFT) computational analysis. Intramolecular Hydrogen Bonds (IHBs) existing Calixarene core cause Cone conformation, supporting to be the best stable state in 1, 2 and 3 compounds. In addition, one needs Natural Bond Orbital (NBO) analyses of current compounds in order to understand nature of these IHBs. Specifically, it has been shown using NBO that the LP *?? interactions for O???O¯H IHBs and the delocalization LP ? ?* for O¯C=O are the major contributions to energy stabilization. Of all conformers of compound 4, Partial Cone has the lowest energy, which can be attributed to devoid of intramolecular hydrogen bond due to the absence of free phenolic groups.Öğe Crystal structure of rac-3-hydroxy-2-(p-tolyl)-2,3,3a,4,7,7a-hexahydro-1H-4,7-methanoisoindol-1-one(International Union of Crystallography, 2015) Aslantaş, Mehmet; Çelik, Cumali; Çelik, Ömer; Karayel, ArzuIn the title compound, C16H17NO2, the cyclohexene ring adopts a boat conformation, and the five-membered rings have envelope conformations with the bridging atom as the flap. Their mean planes are oriented at a dihedral angle of 86.51 (7)_. The molecular structure is stabilized by a short intramolecular C—H…O contact. In the crystal, molecules are linked by O—H…O hydrogen bonds forming chains propagating along [100]. The chains are linked by C—H… ? interactions, forming slabs parallel to (001).Öğe Crystal structures and intermolecular interactions of two novel antioxidant triazolyl-benzimidazole compounds(Maik Nauka-Interperiodica Publishing, 2015) Karayel, Arzu; Özbey, Süheyla; Ayhan Kılcıgil, Gülgün; Kuş, CananThe crystal structures of 5-(2-(p-chlorophenylbenzimidazol-1-yl-methyl)-4-(3-fluorophenyl)-2,4-dihydro-[1,2,4]-triazole-3-thione (G6C) and 5-(2-(p-chlorophenylbenzimidazol-1-yl-methyl)-4-(2-methylphenyl)-2,4-dihydro-[1,2,4]-triazole-3-thione (G4C) have been determined by single-crystal X-ray diffraction. Benzimidazole ring systems in both molecules are planar. The triazole part is almost perpendicular to the phenyl and the benzimidazole parts of the molecules in order to avoid steric interactions between the rings. The crystal structures are stabilized by intermolecular hydrogen bonds between the amino group of the triazole and the nitrogen atom of benzimidazole of a neighboring molecule. © 2015, Pleiades Publishing, Inc.Öğe Design, synthesis and docking studies of benzimidazole derivatives as potential EGFR inhibitors(Elsevier Masson SAS, 2019) Çelik, İsmail; Ayhan Kılcıgil, Gülgün; Güven, Berna; Kara, Zümra; Gürkan Alp, A. Selen; Karayel, Arzu; Onay Beşikçi, ArzuIn this study, a series of benzimidazoles bearing thiosemicarbazide chain or triazole and thiadiazole rings were designed and synthesized. Crystal and molecular structure of the compound 5c has been characterized by single crystal X-ray crystallographic analysis. EGFR kinase inhibitory potencies of synthesized compounds were compared with erlotinib in vitro and most of the compounds exhibited significant activities. Cell culture studies were also carried out for selected compounds and 12b was found to be the most active compound. To understand the binding mode of synthesized benzimidazoles, three compounds (12b, 16, 16c) were selected and placed on the binding site of EGFR tyrosine kinase based on their kinase inhibitor potencies and cell culture studies. Docking study indicated that compound 12b showed two-hydrogen bonding interactions with residues of LYS721 and THR830 at the binding pocket. © 2019 Elsevier Masson SASÖğe Evaluation of Zerumbone as an EGFR Tyrosine Kinase Inhibitor by Molecular Docking Method(University of Ankara, 2023) Yonar, Dilek; Baba, Burcu; Karayel, ArzuObjective: EGFR-TK domain is of great importance in the initiation and progression of various cancer types, especially lung cancer. The existing EGFR-TK inhibitors have numerous side effects, which make them improper to be utilized as cancer therapeutics. In this study, we aimed to analyze the activity of zerumbone as an anticancer agent targeting EGFR by molecular docking approach and to evaluate its activity in comparison with curcumin. Material and Method: MEP and HOMO-LUMO analyses were achieved at B3LYP/6-31G(D,P) level to evaluate electrostatic interactions that affect binding of EGFR with zerumbone and curcumin. Their binding energies were determined by molecular docking and compared with erlotinib as reference ligand. Result and Discussion: Docking studies showed higher bindings (lower binding energy) for curcumin and zerumbone with binding energies -8.0 and -7.6 kcal/mol, respectively, compared to erlotinib (-7.3 kcal/mol). However, there is no significant difference between them. The ?E energy gap of zerumbone was 5.09 eV which implies that this compound has more stability in comparison with curcumin (?E=3.68 eV) and erlotinib (?E=4.29eV). Also, zerumbone showed strong hydrogen bond interactions with EGFR, making it candidate as EGFR inhibitor, as did both in curcumin and erlotinib. It was concluded that zerumbone may have potential for inhibitory activity against EGFRTK.Öğe In silico exploration of O-H center dot center dot center dot X2+ (X = Cu, Ag, Hg) interaction, targeted adsorption zone, charge density iso-surface, O-H proton analysis and topographic parameters theory for calix[6]arene and calix[8]arene as model(Elsevier, 2021) Gassoumi, B.; Ben Mohamed, F. E.; Castro, M. E.; Melendez, F. J.; Karayel, Arzu; Nouar, L.; Ben Ouada, H.In this work, the best adsorption targeted zones of the metal cations Ag2+, Cu2+ and Hg2+ at the surfaces or inside, outside the cavity of the calix[6] (CX[6]), calix[8]arene (CX[8]), NUBMOM (NUB-.) and LAYKUR (LAY-.) have been discussed. For X2+=Ag, Cu and Hg adsorbed onto the surface of CX[6,8], NUB-., and LAY-. and the morphologies of these complexes have been explained, the specific chosen surface structure has interfacial chemical properties to facilitate the stabilization of the cation in each targeted zone. The stability mechanisms have been investigated for the specific systems to understand the role of the cooperativity of the O center dot center dot center dot H (forming a donor-acceptor couple) bonding interactions for good selectivity to the cation in each host-guest in the acetonitrile solvent medium and the gas phase. For this purpose, all the host-guests chemical structures were investigated by the IR spectroscopy and O-H proton approach. The UV-visible absorption spectroscopy and the total DOS Orbital showed that all molecules possess a maximum absorption band in the range between 0.5 and 3.5 eV assigned to pi-pi* or n-pi* transitions, the minimum band is characterized for the CX[6,8]-Cu2+, NUB-.Cu2+ and LAY-.Cu2+, while the highest band is specified for the complexation with the cation Ag2+. The Hirshfeld surface and the molecular electrostatic potential topography have demonstrated the selected targeted zone for the most stable configurations. The nature and the type of interaction formed between the chosen cation and the targeted area of the CX[6,8], NUB-. and LAY-. were typically studied by the Atom in Molecules (AIM) approach via non-covalent interaction (NCI) analyses. According to theoretical calculations, Cu2+, Ag2+ and Hg2+ cations were complexed with CX[6] and CX [8]-arenes in endo and exo-type form. In the endo complexes, it has been observed that Cu2+ and Ag2+ cations enter the lower rim space where calixarene hydroxyl groups are located and form a complex in square planer geometry, as expected. This situation shows that the copper cation is planarly located in the calixarene core. These results show that the theoretical results are in good agreement with the experimental ones. In addition, our simulations point out the calix[6] arene and calix[8]arene were complexed with cations by pinched conformation, corresponding to best stable state. (C) 2021 Elsevier B.V. All rights reserved.Öğe Molecular stabilities, conformational analyses and molecular docking studies of benzimidazole derivatives bearing 1,2,4-triazole as EGFR inhibitors(Springer/Plenum Publishers, 2021) Karayel, ArzuA detailed study of the tautomeric properties, the conformations, and the mechanism behind the anti-cancer properties of 5-{[2-(4-methoxyphenyl)-1H-benzimidazol-1-yl]methyl}-4-ethyl-2,4-dihydro-3H-1,2,4-triazole-3-thione (1), 2-(4-chlorophenyl) (2), 2-phenyl (3), 2-(3,4-dibenzyloxyphenyl) (4), and 2-(4-methoxyphenyl); 4-[2-(piperidin-1-yl)ethyl] (5) has been conducted using density functional theory and molecular docking. The most stable states of all the structures are shown to be in the thione form. The scans of the compounds point out two conformers at PES, one of two conformers for molecule 1 corresponds to X-ray geometry, being the lowest energy state. Current molecules (1, 2, 3, and 5) have one inter-molecular hydrogen bond between NH atom of triazole ring and =O atom in residue ARG817 of the EGFR binding pocket, while compound 4 has different type inter-molecular hydrogen bond which is between N atom in benzimidazole ring and H atom of NH3 in residue LYS721. Off all hydrogen bonds, that of 5 is the strongest one with 2.26 angstrom. Compound 4 has shown the best binding affinity with -10.0 kcal/mol. This compound is the most active compound regarding to the potential anti-cancer activity.Öğe Molecular Structure Analyses of some crystals containing aromatic-structured acids by x-ray diffraction method and quantum mechanical calculations(2015) Aslantaş, Mehmet; Karayel, Arzu; Arslan, Akif; Çelik, ÖmerAromatic-structured acids and their complexes are having with biological importance, in particular molecules which are used in the food industry due to enzymatic activity and antimicrobial properties. In this study, crystal structure analyses were performed by X-ray diffraction method, and biological analysis of synthesized aromatic-structured complex molecules determined. In order to support and compare of the experimental results for these complexes, the quantum mechanical Hartree-Fock (HF) and Density Functional Theory (DFT) methods were investigated by theoretical calculations. Many information at the atomic level for the complex molecules such as, conformations in the unit cell, energies, bond lengths and angles, molecular packing, intra- and inter-molecular hydrogen bonding interactions were presented.Öğe NMR, X-RAY and DFT studies on antioxidant triazolyl-benzimidazole derivatives(Int Union Crystallography, 2011) Karayel, Arzu; Özbey, Süheyla; Ayhan Kılcıgil, Gülgün; Kuş, Canan[Abstract Not Available]Öğe Physical properties of heteroatom doped graphene monolayers in relation to supercapacitive performance(Natl Inst Science Communication-Niscair, 2020) Bharti; Karayel, Arzu; Gupta, Meenal; Ahmad, Gulzar; Kumar, Yogesh; Sharma, ShatendraElectrodes fabricated using graphene are quite promising for electric double layer capacitors. However graphene has the limitations of low 'Quantum Capacitance (QC)' near fermi level due to the presence of Dirac point that can be modified by doping graphene with suitable dopant. The density functional theory DFT calculations are performed for doped graphene using Boron, Sulphur and phosphorus as dopants to improve the quantum capacitance of electrodes fabricated using graphene. The calculations are performed at temperatures of 233, 300 and 353 degrees K. From present calculations no significant temperature dependence of quantum capacitance is observed, however a marked increase in QC of value above 58Fcm(-2) is seen. Forphosphorus and Sulphur doped graphene a significant energy gap shift of similar to 1.5 eV from the Fermi level is observed that significantly increases the QC at Fermi level to a high value of similar to 35 mu Fcm(-2). With boron dopant as well, a shift of energy gap similar to 1.25eV from the Fermi level is observed. The shift in Dirac point increases quantum capacitance at Fermi level that in turn can increase the energy density of supercapacitor remarkably. The effect of increasing doping concentration on quantum capacitance is also investigated. These results suggest that doping of graphene may result in significant increase in QC near Fermi level, if the dopants are selected carefully depending upon the use of graphene as a positive or negative electrode. The results of these calculations reveal that the problem of low QC of graphene in the range of interest can be addressed by modifying itssurface and structure chemistry which may increase energy density in supercapacitors.Öğe Restricted rotation around the methylene bridge of 5-(2-p-(chlorophenyl)benzimidazole-1-yl)methyl-4-(o-substitutedphenyl)-2,4-dihydro-[1,2,4]-triazole-3-thiones as evidenced by NMR, X-RAY and DFT studies and the importance of low energy rotational conformers(Elsevier B.V., 2019) Karayel, Arzu; Özbey, Süheyla; Kuş, Canan; Ayhan Kılcıgil, GülgünThe aim of this study was to clarify the restricted rotation around the –CH2–N bond of the compounds, 5-(2-(p-chlorophenylbenzimidazol-1-yl-methyl)-4-(o-methylphenyl)-2,4-dihydro-[1,2,4]-triazole-3 thione [1], 4-(o-florophenyl)- [2], 4-(o-chlorophenyl)- [3] and 4-(o-bromophenyl)- [4], which are some benzimidazole derivatives showing antioxidant properties. In NMR spectra of relevant compounds, because of the hindered rotation around the methylene bridge, methylene protons appear as an AB quartet in DMSO?d6. The high temperature NMR spectra (296.1 K, 308.1 K, 323.1 K and 332.1 K) for the compound 1 show similar behavior in DMSO?d6. The NMR spectra in different solvents point out the same manner. The preventing of free rotation in the methylene bridge caused by the existence of substituents at the second position of the phenyl group connected to triazole ring was supported by both the experimental results (NMR and X-ray) and the theoretical results in the gas phase. The hindered rotation of compound 1 also investigated by applying the polarizable continuum model (PCM) for different solvents (DMSO?d6 and C6D6), as did in NMR. Additionally, potential energy surface (PES) scan revealed that each compound has two possible conformers. © 2018 Elsevier B.V.Öğe Restricted rotation around the methylene bridge of 5-(2-p-(chlorophenyl)benzimidazole-1-yl)methyl-4-(o-substitutedphenyl)-2,4-dihydro-[1,2,4]-triazole-3-thiones as evidenced by NMR, X-RAY and DFT studies and the importance of low energy rotational conformers(Elsevier B.V., 2019) Karayel, Arzu; Özbey, Süheyla; Kuş, Canan; Ayhan Kılcıgil, GülgünThe aim of this study was to clarify the restricted rotation around the –CH2–N bond of the compounds, 5-(2-(p-chlorophenylbenzimidazol-1-yl-methyl)-4-(o-methylphenyl)-2,4-dihydro-[1,2,4]-triazole-3 thione [1], 4-(o-florophenyl)- [2], 4-(o-chlorophenyl)- [3] and 4-(o-bromophenyl)- [4], which are some benzimidazole derivatives showing antioxidant properties. In NMR spectra of relevant compounds, because of the hindered rotation around the methylene bridge, methylene protons appear as an AB quartet in DMSO?d6. The high temperature NMR spectra (296.1 K, 308.1 K, 323.1 K and 332.1 K) for the compound 1 show similar behavior in DMSO?d6. The NMR spectra in different solvents point out the same manner. The preventing of free rotation in the methylene bridge caused by the existence of substituents at the second position of the phenyl group connected to triazole ring was supported by both the experimental results (NMR and X-ray) and the theoretical results in the gas phase. The hindered rotation of compound 1 also investigated by applying the polarizable continuum model (PCM) for different solvents (DMSO?d6 and C6D6), as did in NMR. Additionally, potential energy surface (PES) scan revealed that each compound has two possible conformers. © 2018 Elsevier B.V.Öğe Revealing the effect of Co/Cu (d7/d9) cationic doping on an electronic acceptor ZnO nanocage surface for the adsorption of citric acid, vinyl alcohol, and sulfamethoxazole ligands: DFT-D3, QTAIM, IGM-NCI, and MD analysis(ELSEVIER SCIENCE SA, 2023) Gassoumi, B.; Mahmoud, A.M. Ahmed; Nasr, S.; Karayel, Arzu; Özkınalı, SevilThe electron-spin duality and propagation of the active sites of free electrons are of interest for adsorbing the guests and fixing them with strong hydrogen bonds (HB). The coherence of the systems with the guests is one of the main parameters that favor the experimentation of new systems on primary column adsorption phenomena. The stability and the adaptable symmetries in all directions justify the use of a “nanocage” (ZnO) for studying adsorption phenomena. The formation of stable electronic charge transfer paths between sites occupied by very stable atomic orbitals ensures the success of the adsorption of the ligands. Electronic characterization (MES, FMO, DOS, and cationic doping) is used to describe the movement of the intra-Cu-Co/Zn19O20 electrons. The phenomena of charge transfer, stability, types of orbital occupations, adsorption sites, electron migration direction, conductivity, and reactivity of such systems are thoroughly explored. Based on these findings, the efficiency of a Cu–Co/Zn19O20 nanocage to adsorb three different ligands (medical ligands, prostate biomarkers, and antibiotics) is studied. From the reactivity parameter discussions, it is found that the copper or cobalt-doped nanocage-Citric Acid has a strongly electronegative index (4.40 eV and 4.91 eV) and hardness (1.99 eV and 1.82 eV) properties. The Fourier transform infrared analyses and orbital localizations (? and ?) clearly demonstrate that the charge transfer occurs inter-surface, from nanocages to adsorbed ligands. Bader’s theory analysis for the adsorption ligands VA (Vinyl Alcohol), CA (Citric Acid), and SMX (Sulfamethoxazole) by the doped copper and cobalt nanocages demonstrates that these systems are much more adequate for adsorbing the ligand antibiotics than the other hosts. The highly adsorbent energy of sulfamethoxazole by Cu–Zn19O20 is equal to ? 582.86 kJ. mol-1. The IGM-NCI/ELF analyses support these findings, revealing that the Cu/Co–Zn19O20 nanocages adsorb SMX via hydrogen bonding and van der Waals interactions, as they also did in DFT-D3 and FT-IR analyses. LOL analyses support this claim by visualizing single-pair spins in excess surrounding acceptor atoms (O) in the two systems. Molecular dynamics simulations show that SMX is quickly adsorbed by nanocages of Zn19O20 doped with copper (d9) or cobalt (d7).Öğe Synthesis and structural characterization of 3-[1-[4-(2-methylpropyl)phenyl] ethyl]-6-(4-fluorophenyl)-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole(Cambridge Univ Press, 2019) Gündoğdu, Gülsüm; Karayel, Arzu; Pen Aytaç, Sevim; Tozkoparan, Birsen; Kaynak, Filiz Betül3-[1-[4-(2-Methylpropyephenyl] ethyl]-6-(4-fluorophenyl)-1,2,4-triazolo [3,4-b] -1,3,4-thiadiazole (C21H21FN4S) has been synthesized as a member of a series of triazolothiadiazoles having NSAIDs moieties with cytotoxic activity. The crystal structure of this new compound has been solved and refined using conventional laboratory X-ray powder diffraction data and optimized using density functional techniques. The final structure solution was achieved by Rietveld refinement using soft restraints on all non-H atom bond lengths and angles. This compound crystallizes in P (1) over bar space group, with the unit cell parameters a= 5.5880(4) angstrom, b = 9.3074(7) angstrom, c = 19.497(4) angstrom, alpha= 99.311 (10)degrees, beta= 91.925(9)degrees, gamma= 98.199(6)degrees, and V= 988.8(2) angstrom(3). To complement and verify the structure solution of the compound, the density functional theory (DFT) calculations were performed by using the local density approximation and the generalized gradient approximation for exchange-correlation energy. In order to see the effect of the van der Waals interactions on the electronic structure, the relevant structure was also optimized with B3LYP-D2, PBE-D2, and optB88-vdW functionals. The refined crystal structure was confirmed by the DFT calculations. The best agreement with the experimental structure was achieved by optB88-vdW functional. (C) 2019 International Centre for Diffraction Data.Öğe Synthesis, characterization, conformational equilibrium and intramolecular hydrogen bond analysis of Novel Azocalix[4]arenes including acryloyl moiety using DFT studies(Elsevier B.V., 2019) Özkınalı, Sevil; Karayel, ArzuAzocalix[4]arenes were synthesized via diazo-coupling reaction with aniline in 1:1, 1:2, 1:3 and 1:4 molar ratio. Novel Azocalix[4]arenes having Acryloyl moiety were prepared esterification reaction with metallic sodium and Acryloyl chloride with the same molar ratio of Azocalix[4]arene derivatives. The spectroscopic characterizations of the compounds were made by using IR, UV–Vis, 1H NMR and 13C NMR spectroscopies. In our study, the validation of the exact conformation of Azocalix[4]arene existing in a Cone, Partial Cone, 1,2-Alternate and 1,3-Alternate was realized by spectroscopic and DFT analyses. These results reveal that the compounds exist in the Cone conformation because of the existence of Intramolecular Hydrogen Bonds (IHBs) in the calixarene core. According to the conformational analysis, Cone conformation corresponds to the minimum energy for compounds 6, 7 and 8, as well. Both DFT and NMR results confirmed that a conformational rearrangement of compound 9 is 1,3-Alternate conformer. The experimental results were correlated with the theoretical calculations. In addition, Natural Bond Orbital (NBO) calculations were used to examine the electronic characteristics of the intramolecular hydrogen bonds. NBO energies show that the main contributions to energy stabilization correspond to LP ? ?* interactions for IHBs, O???O–H and the delocalisation LP ? ?* for O–C[dbnd]O. © 2018 Elsevier B.V.Öğe SYNTHESIS, CHARACTERIZATION, THERMAL, X-RAY, AND DFT ANALYSES OF 6-TERT-BUTYL 3-ETHYL 2-[(3-METHOXY/5-BROMO)-2-HYDROXY AND (3-NITRO/3-METHOXY)BENZYLIDENEAMINO]- 4,5-DIHYDROTHIENO[2,3-C]PYRIDINE-3,6(7H)-DICARBOXYLATE(Pleiades Publishing Inc, 2021) Çolak, Naki; Karayel, Arzu; Buldurun, Kenan; Turan, NevinIn this work, 6-tert-butyl 3-ethyl 2-amino-4,5-dihydrothieno[2,3-c]pyridine-3,6(7H)-dicarboxylate is synthesized from starting tert-butyl 4-oxopiperidine-1-carboxylate, ethyl cyanomalonate, and sulfur, and then, coupled with same aromatic aldehyde affords the corresponding Schiff base compounds. These compounds (2a-d) are characterized using FTIR, H-1 and C-13 NMR spectroscopic methods. The crystal and molecular structure of (E)-6-tert-butyl 3-ethyl 2-((2-hydroxy-3-methoxybenzylidene)amino)-4,5-dihydrothieno[2,3-c]pyridine-3,6(7H)-dicarboxylate (2a) is characterized by the X-ray crystallographic analysis. Compound 2a crystallizes in the monoclinic space group P2(1)/c. The molecular and crystal structure is stabilized by two O-HMIDLINE HORIZONTAL ELLIPSISN and O-HMIDLINE HORIZONTAL ELLIPSISO intramolecular hydrogen bonds (OMIDLINE HORIZONTAL ELLIPSISN and OMIDLINE HORIZONTAL ELLIPSISO are 2.598(5) angstrom and 2.990(5) angstrom, respectively; O-HMIDLINE HORIZONTAL ELLIPSISN = 147 degrees and O-HMIDLINE HORIZONTAL ELLIPSISO = 134 degrees). According to DFT, compound 2d also shows the intramolecular hydrogen bonding, while there is no this type of interaction in compound 2b and 2c.Öğe The intramolecular hydrogen bond analysis in biologically active 5-fluoro-1h-indole-2,3-dione-3-thiosemicarbazones derivatives by experimental and theoretical methods(Int Union Crystallography, 2015) Karayel, Arzu; Kayanak, F. Betül; Karalı, Nilgün Lütfiye; Özbey, Süheyla[Abstract Not Available]Öğe Theoretical assessment of calix[4]arene-N-beta-ketoimine (n=1-4) derivatives: Conformational studies, optoelectronic, and sensing of Cu(2+)cation(Springer, 2021) Gassoumi, B.; Ben Mohamed, F. E.; Khedmi, N.; Karayel, Arzu; Echabaane, M.; Ghalla, H.; Ben Chaabane, R.Herein, we have investigated the key functions of the calix[4]arene, abbreviated as CX [1], and designed its several derivatives by substitution of the functional groups. Molecular geometry provides an intuitive understanding of the effect of functional groups on various physical properties. The addition of the N-beta -ketoimine (n=1-4) ligands has a direct effect on the stretching vibration of the H-bonding interaction. The results showed that all molecules possess absorption bands at 190 nm and in the range between 200 and 300 nm assigned to pi-pi* and n-pi* transitions. HOMO-LUMO energy gap of the CX[4]-N-beta -ketoimine, one with chemical hardness of 1.62 eV, has been found to be 3.24 eV calculated at B3LYP/6-31+G(d) level of theory. This finding explains the good kinetic stability of this compound. The large values of electrophilicity make the current molecules as a good electrophilic species. The atom in molecule (AIM) and the reduced density gradient (RDG) analyses showed the type and the strength of the interactions taking place between Cu2+ and the beta -ketoimine ligands.Öğe Theoretical study of hydrogen adsorption in Ti-decorated capped carbon nanotube(Taylor and Francis Ltd., 2017) Niaz, Shanawer; Abbasian, Hamed; Badar, Manzoor Ahmad; Anwar-ul-Haq, M; Karayel, ArzuWe present ab initio study using dispersion-corrected density functional theory calculations to investigate the hydrogen interaction with Ti-coated, one end closed, single-walled carbon nanotube (SWCNT). Our results demonstrate that a single Ti atom binds up to five hydrogen molecules on SWCNT cap top, whereas adsorption of four hydrogen molecules is energetically more favourable. The analyses fromadsorption energy profile, highest occupied molecular orbital–lowest unoccupied molecular orbital gap and Mulliken charge distribution show contrast in first hydrogen molecule adsorption compared with the rest of four configurations. This is clearly due to the strongly different bonding nature of first hydrogen adsorption among others, between hydrogen molecules and Ti-coated SWCNT. These results not only support our understanding of adsorption nature of hydrogen in Ti-coated SWCNTs but also suggest new directions for smart storage techniques. © 2017 Informa UK Limited, trading as Taylor & Francis Group.
