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Öğe Crystal Structure of (E)-3-[(4-Ethylphenylimino)methyl]benzene-1,2-diol and (E)-3-[( 4-Butylphenyl imino)methyl]benzene-1,2-diol.(Int Union Crystallography, 2009) Kelesoglu, Zeynep; Kosar, Basak; Albayrak, Cigdem; Odabasoglu, Mustafa; Buyukgungor, Orhan[No abstract available]Öğe Crystal structure, spectroscopic investigations and quantum chemical calculation studies of (3aR,6S,7aR)-7a-bromo-6-methyl-2-[(4-methylphenyl)sulfonyl]-1,2,3,6,7,7a-hexahydro-3a,6-epoxyisoindole: A combined experimental and theoretical studies(Elsevier, 2016) Alasalvar, Can; Demircan, Aydin; Kosar, Basak; Pekacar, Ali Ihsan; Buyukgungor, OrhanThe crystal structure and spectroscopic properties of (3aR,65,7aR)-7a-bromo-6-methyl-2-[(4-methylphenyl)sulfonyl]-1,2,3,6,7,7a-hexahydro-3a,6-epoxyisoindole were determined by X-ray diffraction, IR and (CNMR)-C-13 and H-1 NMR spectroscopytechniques. We investigate molecular and crystal structure of the new sulfonamide, which was derived from an environmental friendly cyclization reaction in water. This work allow to the development of a stereo-selective tandem allylamine isomerization/Diels Alder cyclo-addition sequence led to rapid assembly of complex nitrogen containing heterocycles. The molecular geometry from X-ray determination, vibrational frequencies and NMR shifts values of the title compound in the ground state have been calculated by using CAM-B3LYP and B3LYP methods with 6-311++G(d,p) basis sets. The calculated results show that the optimized geometry can well regenerate the crystal structure and theoretical vibrational frequencies and chemical shift data are in good agreement with experimental data. Besides, it is examined nonlinear optic properties, molecular electrostatic potential map and HOMO-LUMO orbitals of the molecule. (C) 2016 Elsevier B.V. All rights reserved.Öğe (E)-2-[(4-Chlorophenyl)iminomethyl]-5-methoxyphenol and (E)-2-[(2-chlorophenyl)iminomethyl]-5-methoxyphenol: X-ray and DFT-calculated structures(Int Union Crystallography, 2009) Kosar, Basak; Albayrak, Cigdem; Odabasoglu, Mustafa; Buyukgungor, OrhanThe crystal structures of the title 4-chlorophenyl, (I), and 2-chlorophenyl, (II), compounds, both C14H12ClNO2, have been determined using X-ray diffraction techniques and the molecular structures have also been optimized at the B3LYP/6-31 G(d, p) level using density functional theory (DFT). The X-ray study shows that the title compounds both have strong intramolecular O-H center dot center dot center dot N hydrogen bonds and that the crystal networks are primarily determined by weak C-H center dot center dot center dot pi and van der Waals interactions. The strong intramolecular O-H center dot center dot center dot N hydrogen bond is evidence of the preference for the phenol-imine tautomeric form in the solid state. The IR spectra of the compounds were recorded experimentally and also calculated for comparison. The results from both the experiment and theoretical calculations are compared in this study.Öğe Hexakis(4-phormylphenoxy)cyclotriphosphazene: X-ray and DFT-calculated structures(Maik Nauka/Interperiodica/Springer, 2010) Albayrak, Cigdem; Kosar, Basak; Odabasoglu, Mustafa; Buyukgungor, OrhanThe crystal structure of hexakis(4-phormylphenoxy)cyclotriphosphazene is determined by using X-ray diffraction and then the molecular structure is investigated with density functional theory (DFT). X-Ray study shows that the title compound has C-HaEuro broken vertical bar pi interaction with phosphazene ring. The molecules in the unit cell are packed with Van der Waals and dipole-dipole interactions and the molecules are packed in zigzag shaped. Optimized molecular geometry is calculated with DFT at B3LYP/6-311G(d,p) level. The results from both experimental and theoretical calculations are compared in this study.Öğe Molecular structure of (Z)-6-[(5-chloro-2-hydroxyphenylamino) methylene]-3-(diethylamino)cyclohexa-2,4-dienone: A combined experimental and theoretical study(Elsevier, 2011) Kosar, Basak; Albayrak, Cigdem; Odabasoglu, Mustafa; Buyukgungor, OrhanThe crystal structure and spectroscopic properties of ortho-hydroxy Schiff base compound (Z)-6-[(5-chloro-2-hydroxyphenylamino)methylene]-3-(diethylamino)cyclohexa-2,4-dienone were determined by X-ray diffraction, IR and UV-Vis spectroscopy techniques. Molecules of the compound exist as NH tautomeric form in solid state. The gas phase geometry optimizations of two possible tautomeric forms of the title compound were achieved using OFT calculations at B3LYP/6-31G(d,p) level of theory. In order to describe the potential energy barrier belonging to the intramolecular proton transfer and to observe the effects of transfer on the molecular geometry, a relaxed potential energy surface (PES) scan was performed based on the optimized geometry of the NH tautomeric form by varying the redundant internal coordinate, N-H bond distance. At the same level of theory, the vibrational frequencies were calculated and compared with the experimental frequencies. The electronic absorption spectra of the tautomers were calculated using time-dependent density functional theory (TO-OFT) method started from solution phase optimized geometries and compared with the experimental ones. Crown Copyright (c) 2010 Published by Elsevier B.V. All rights reserved.Öğe Molecular structure, spectroscopic investigations, second-order nonlinear optical properties and intramolecular proton transfer of (E)-5-(diethylamino)-2-[(4-propylphenylimino)methyl]phenol: A combined experimental and theoretical study(Pergamon-Elsevier Science Ltd, 2012) Kosar, Basak; Albayrak, Cigdem; Ersanli, Cem Cuneyt; Odabasoglu, Mustafa; Buyukgungor, OrhanThis work presents a combined experimental and theoretical study on an ortho-hydroxy Schiff base compound, (E)-5-(diethylamino)-2-[(4-propylphenylimino)methyl]phenol. The crystal structure and spectroscopic properties of the compound have been determined by using X-ray diffraction, IR and UV-vis spectroscopy techniques. The electronic structure, vibrational frequencies and electronic absorption spectra have been investigated from the calculative point of view. A relaxed potential energy surface scan has been performed based on the optimized geometry of OH tautomeric form to describe the potential energy barrier belonging to intramolecular proton transfer and to observe the effects of transfer on the molecular geometry. The second-order nonlinear optical properties have been investigated based on the first static hyperpolarizability (beta) by using the density functional theory. (C) 2012 Elsevier B.V. All rights reserved.Öğe Spectroscopic investigations and quantum chemical computational study of (E)-4-methoxy-2-[(p-tolylimino)methyl]phenol(Pergamon-Elsevier Science Ltd, 2011) Kosar, Basak; Albayrak, CigdemIn this work the electronic structure of (E)-4-methoxy-2-[(p-tolylimino)methyl]phenol has been characterized by the B3LYP/6-31G(d) level by using density functional theory. The experimental infrared and electronic absorption spectra have been obtained and compared with the theoretically obtained ones. Molecular electrostatic potential map has been evaluated; natural bond orbital and frontier molecular orbitals analysis have been performed from the optimized geometry. The energetic behavior of the title compound has been examined in solvent media using polarizable continuum model. The non-linear optical properties have been computed with the same level of theory. In addition, the changes of thermodynamic properties have been obtained in the range of 100-500 K. (C) 2010 Elsevier B.V. All rights reserved.Öğe Synthesis and characterization of Cu(II) complexes of pyrazine-2,3-dicarboxylicacid(Pergamon-Elsevier Science Ltd, 2011) Tascioglu, Sulin; Aydin, Adnan; Yalcin, Bahattin; Kaki, Esra; Andac, Omer; Buyukgungor, Orhan; Kosar, BasakFour copper(II) coordination polymers, {[Cu(pz(COO)(2))(H2O)](4)center dot HBr}(n) (1). {[Cu(pz(COO)(2))(NH3)(2)]center dot H2O}(n) (2), {[Cu3H2(pz(COO)(2))(4)(H2O)(3)]center dot 2H(2)O}(n) (3) and {[Cu-2(pz(COO)(2))(2)(NH3)(2)(H2O)(3)][Cu(pz(COO)(2))(NH3) (H2O)(2)][Cu(pz(COO)(2))(NH3)(H2O)]center dot 2H(2)O}(n) (4) were synthesized using pyrazine-2,3-dicarboxylic acid, CuBr2, 2-(2-aminoethylamino)ethanol/triethanol amine/ammonia in a methanol:water (1:1) solution, and the mixed ligand complexes were characterized by spectroscopic methods, thermal and elemental analysis, and magnetic susceptibility. Complexes 2 and 4 were also characterized by means of single crystal X-ray crystallography. The characterizations show that the complexes have polynuclear molecular structures, except for complex 2, and all of the complex structures form polymeric chains. Complex 4 has a pseudo-merohedral twin structure. (C) 2011 Elsevier Ltd. All rights reserved.Öğe Synthesis, spectroscopic characterizations and quantum chemical computational studies of (Z)-4-[(E)-p-tolyldiazenyl]-6-[(2-hydroxyphenylamino)methylene]-2-methoxycyclohexa-2,4-dienone(Pergamon-Elsevier Science Ltd, 2012) Odabasoglu, Mustafa; Albayrak, Cigdem; Kosar, Basak; Buyukgungor, OrhanIn this study, the molecular structure and spectroscopic properties of title compound were characterized by X-ray diffraction, FT-IR and UV-vis spectroscopies. These properties of title compound were also investigated from calculative point of view. The X-ray diffraction and FT-IR analyses reveal the existence of keto form in the solid state. UV-vis spectra were recorded in different organic solvents. The results show that title compound exists in both keto and enol forms in DMSO, EtOH but it exists in enol form in benzene. In addition, the title compound in DMSO showed new absorption band at 436 nm due to the high ionizing effect of this solvent. The geometry optimization of title compound in gas phase was performed using DFT method with B3LYP applying 6-311G(d,p) basis set. TD-DFT calculations starting from optimized geometry were carried out in gas phase to calculate excitation energies of title compound. The nonlinear optical properties were computed with the same level of theory and title compound showed a good second order nonlinear optical property. In addition, thermodynamic properties were obtained in the range of 100-500K. (C) 2012 Elsevier B.V. All rights reserved.Öğe Synthesis, spectroscopic, molecular and computational structure characterizations of (E)-2-ethoxy-6-[(phenylimino)methyl]phenol(Elsevier, 2010) Albayrak, Cigdem; Kosar, Basak; Demir, Serkan; Odabasoglu, Mustafa; Buyukgungor, OrhanThe structure of (E)-2-ethoxy-6-[(phenylimino)methyl]phenol was characterized by X-ray diffraction, IR and electronic spectroscopy. The title compound prefers enol form in solid state as to X-ray and IR results. UV-Vis spectra of the title compound were recorded in various solvents. The results show that the molecule exists only enol form even in solvent media. Electronic structure and spectroscopic properties of title compound were investigated from calculative point of view. DFT/B3LYP optimization was performed based on X-ray Geometry applying 6-311 G(d,p) basis set. TD-DFT calculations starting from optimized geometry were carried out in both gas and solution phase to calculate excitation energies of enol and keto tautomers. Vibrational frequency analysis was performed at the optimized geometry with the same level of theory. (c) 2009 Elsevier B.V. All rights reserved.Öğe Theoretical and Experimental Studies on Electronic Structure, Cocrystallization, and Intramolecular Proton Transfer of Two Tautomers: (E)-2-{[2-(Hydroxymethyl)phenylimino]methyl}-5-methoxyphenol and (z)-6-{[2-(Hydroxymethyl)phenylamino] methylene}-3-methoxy-cyclohexa-2,4-dienone(Wiley, 2011) Kosar, Basak; Albayrak, Cigdem; Odabasoglu, Mustafa; Buyukgungor, OrhanIn this work, the structure of (E)- 2-{[2-(hydroxymethyl) phenylimino] methyl}-5-methoxyphenol was characterized by X-ray single crystal diffraction technique, infrared spectroscopy, and quantum chemical computational methods as both experimental and theoretically. The compound crystallizes in the triclinic space group P1 with a = 9.4601 (5) angstrom, b = 11.7273 (7) angstrom, c = 12.4400 (8) angstrom, alpha = 88.179 (5)degrees, b = 71.442 (4)degrees, gamma = 84.977 (5)degrees, and Z = 4. X-Ray study shows that both enol-imine and keto-amine tautomeric forms coexist in the asymmetric unit as two independent molecules. The molecular geometry was also optimizedat the B3LYP/6-311G(d,p) level by using density functional theory started from the crystallographically achieved parameters of molecule. From the optimized geometry of the molecule, molecular electrostatic potential was evaluated, frontier molecular orbitals and natural bond orbital analysis were performed, and vibrational frequencies were computed theoretically. The polarizable continuum model calculations starting from the optimized geometry were also carried out in both gaseous and solution phase to investigate the energetic behavior and dipole moment of the title compound with the same level of theory. (C) 2010 Wiley Periodicals, Inc. Int J Quantum Chem 111: 3654-3663, 2011Öğe THERMODYNAMIC AND SECOND-ORDER NON-LINEAR OPTICAL PROPERTIES OF TAUTOMERIC FORMS OF (E)-4-METHOXY-2-[(4-NITROPHENYL)IMINOMETHYL]PHENOL: A DENSITY FUNCTIONAL STUDY(World Scientific Publ Co Pte Ltd, 2011) Kosar, BasakThis work presents a computational study on the tautomeric forms of (E)-4-Methoxy-2[(4-nitrophenyl)iminomethyl]phenol, an ortho-hydroxy Schiff base compound. The electronic structure of title compound has been characterized at the B3LYP/6-311G(d,p) level of density functional theory. The first hyperpolarizability values have been obtained from the molecular polarizabilities for both tautomers. The second-order non-linear optical properties have been investigated based on their relationships with the natural bond orbitals and frontier molecular orbitals. The changes of thermodynamic properties with temperature going from 100 K to 300 K have been investigated for the reactants and the reaction products tautomers. Tautomeric equilibrium constant derived from the difference between the Gibbs free energies of tautomers has been obtained at different temperatures. The relationship between formation enthalpy and entropy changes has been investigated with the enthalpy-entropy compensation.
