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Öğe Direct and solvent-assisted thione-thiol tautomerism in 5-(thiophen-2-yl)-1,3,4-oxadiazole-2(3H)-thione: Experimental and molecular modeling study(Elsevier, 2014) Arslan, N. Burcu; Ozdemir, Namik; Dayan, Osman; Dege, Necmi; Koparir, Metin; Koparir, Pelin; Muglu, HalitThe compound has been synthesized and characterized by IR, NMR and X-ray diffraction. Quantum chemical calculations at B3LYP/6-311++G(d,p) level were performed to study the molecular and spectroscopic properties, conformational equilibrium, thione <-> thiol tautomerism and intermolecular double proton transfer reaction of the compound. The obtained structural and spectroscopic results are well in agreement with the experimental data. The solvent effect on the proton transfer reaction was investigated in three solvents using the polarizable continuum model approximation and solvent-assisted mechanism. The anti-thione tautomer is the most stable isomer among the four possible structural forms both in the gas phase and in solution phase. A high tautomeric energy barrier is found for the tautomerism between the anti and syn forms of the compound, indicating a quite disfavored process. Although the presence of one methanol or water solvent molecule significantly lowers the energy barrier, it is not adequate for the reaction to occur. (C) 2014 Elsevier B.V. All rights reserved.Öğe Experimental and ab initio computational studies on N-(4-nitrobenzoyl)-N?-(1,5-dimethyl-3-oxo-2-phenyl-1H-3(2H)-pyrazolyl)-thiourea(Int Union Crystallography, 2011) Arslan, N. Burcu; Kazak, Canan; Aydin, Fatma[Anstract Not Available]Öğe Experimental and theoretical investigation of N-(4-Nitrobenzoyl)-S-(2-hydroxyethyl)-carbamodithioate(Taylor and Francis Ltd., 2021) Arslan, N. Burcu; Aydın, Fatma; Kazak, CananThe title molecule, N-(4-Nitrobenzoyl)-S-(2-hydroxyethyl)-carbamodithioate, (C10H10N2O4S2), was synthesized and its structure verified by single crystal X-ray diffraction and FT-IR, H-1-NMR, C-13-NMR spectroscopic techniques. The molecular geometry and vibrational frequencies of the title compound in the ground state have been calculated by using the density functional theory (DFT) method with 6-311 G(d,p) basis set, and compared with the experimental data. The calculated results show that the optimized geometries can well reproduce the crystal structural parameters. A detailed vibrational spectral analysis has been carried out and assignments of observed fundamental bands have been proposed on basis of peak positions. The scaled theoretical frequencies show very good agreement with experimental values. Besides, a molecular electrostatic potential (MEP), frontier molecular orbitals (FMOs) analysis and thermodynamic properties of the title compound were investigated by theoretical calculations.Öğe Experimental and theoretical investigation of N-(4-nitrobenzoyl)-S-(cyclohexyl)-dithiocarbamate, N-(4-nitrobenzoyl)-S-benzyldithiocarbamate(Elsevier Science Bv, 2018) Arslan, N. Burcu; Kazak, Canan; Aydin, FatmaTwo new dithiocarbamate molecules were synthesized and characterized by H-1 NMR, C-13 NMR, IR, and structural X-ray diffraction techniques. The molecular geometry, vibrational frequencies of the title compounds in the ground state have been calculated by using the Hartree-Fock (HF) and density functional theory (DFT) methods with 6-31G(d) basis set, also gauge-independent atomic orbital (GIAO) H-1 and C-13 NMR chemical shift values of the title compound (I) have been calculated by the same methods and compared with the experimental data. The calculated results show that the optimized geometries can well reproduce the crystal structural parameters. A detailed vibrational spectral analysis has been carried out and assignments of observed fundamental bands have been proposed on basis of peak positions. The scaled theoretical frequencies showed very good agreement with experimental values. In addition, the computed H-1 and C-13 NMR chemical shift values are in line with experimental data. To determine conformational flexibility, the molecular energy profile of the title compounds were obtained in respect of the selected torsion angle, which were varied from -180 degrees to +180 degrees in steps of 10 degrees. Besides, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP)analysis and thermodynamic properties were investigated by theoretical calculations. (C) 2017 Elsevier B.V. All rights reserved.Öğe N-(4-Nitrobenzoyl)-N?-(1,5-dimethyl-3-oxo-2-phenyl-1H-3(2H)-pyrazolyl)-thiourea hydrate: Synthesis, spectroscopic characterization, X-ray structure and DFT studies(Pergamon-Elsevier Science Ltd, 2012) Arslan, N. Burcu; Kazak, Canan; Aydin, FatmaThe title molecule (C19H17N5O4S center dot H2O) was synthesized and characterized by IR-NMR spectroscopy. MS and single-crystal X-ray diffraction. The molecular geometry, vibrational frequencies and gaugeindependent atomic orbital (GIAO) H-1 and C-13 NMR chemical shift values of the compound in the ground state have been calculated by using the density functional theory (DM method with 6-31G(d) basis set, and compared with the experimental data. All the assignments of the theoretical frequencies were performed by potential energy distributions using VEDA 4 program. The calculated results show that the optimized geometries can well reproduce the crystal structural parameters, and the theoretical vibrational frequencies and H-1 and C-13 NMR chemical shift values show good agreement with experimental data. To determine conformational flexibility, the molecular energy profile of the title compound was obtained with respect to the selected torsion angle, which was varied from -180 degrees to +180 degrees in steps of 10 degrees. Besides, molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis and thermodynamic properties of the compound were investigated by theoretical calculations. (C) 2011 Elsevier B.V. All rights reserved.Öğe N-Benzoyl-S-(undecyl)-dithiocarbamate: Synthesis, characterization, X-ray single crystal structure, thermal behavior and computational studies(Elsevier, 2020) Aydin, Fatma; Arslan, N. Burcu; Aslan, KadirA new dithiocarbamate molecule, named as N-benzoyl-S-(undecyl)-dithiocarbamate (C19H29NOS2), was synthesized and characterized by (HNMR)-H-1, (CNMR)-C-13, FT-IR spectroscopic methods. X-ray analysis of the crystal structure of title compound showed the presence of triclinic space group with a = 4.2417 (8) angstrom, b = 20.010 (4) angstrom, c = 27.959 (6) angstrom, Z = 4, V = 2338.9 angstrom(3). Detailed investigation of molecular packing of the molecule indicated the presence of intermolecular hydrogen bond between C1-H1 center dot center dot center dot S4(i) and C24 -H24 center dot center dot center dot S2(v) that generates R-2(2) (10) motifs, and intermolecular hydrogen bonds between N1-H111 center dot center dot center dot S4(ii) and N2-H222 center dot center dot center dot S2(iv) atoms that forms R-2(2) (7) rings. Thermal properties of the title compound were investigated by thermogravimetric analysis (DTA/TG) and differential scanning calorimetry (DSC). Molecular electrostatic potential (MEP), the HOMO and LUMO energies and thermodynamic parameters of the title compound were calculated using density functional theory (DFT) with B3LYP/6-311G (d,p) level. (C) 2019 Published by Elsevier B.V.Öğe Palladium(II) complexes bearing bidentate pyridyl-sulfonamide ligands: Synthesis and catalytic applications(Pergamon-Elsevier Science Ltd, 2015) Dayan, Serkan; Cetin, Ahmet; Arslan, N. Burcu; Ozpozan, Nilgun Kalaycoiglu; Ozdemir, Namik; Dayan, OsmanNew palladium(II) complexes aPd(1-5)(2)], 6-10, (1-5 = bidentate pyridyl-sulfonamide ligands)) were obtained from the reaction between Pd(OAc)(2) and bidentate pyridyl-sulfonamide ligands. The synthesized compounds were characterized by elemental analysis, TG, NMR, IR and X-ray diffraction. The Pd(II) complexes 6-10 were investigated as catalysts for the oxidation of benzyl alcohol to benzaldehyde in the presence of periodic acid as the oxidant and acetonitrile as the solvent under reflux. All the complexes were moderately active catalysts for the catalytic reaction (the oxidation of benzyl alcohol to benzaldehyde), with good yields under mild conditions. (C) 2014 Elsevier Ltd. All rights reserved.Öğe Synthesis, characterization, and crystal structure of bis[4-(3?-benzoyl)thiocarbamidophenyl]ether(Pleiades Publishing Inc, 2014) Aydin, F.; Aykac, D.; Arslan, N. Burcu; Kazak, C.The title compound, bis[4-(3'-benzoyl)thiocarbamidophenyl]ether, was synthesized by the reaction of benzoylisothiocyanate with 4,4'-diaminodiphenylether in aprotic solvent. The structure was determinated by means of elemental analysis and FT-IR, H-1-NMR, (1)3C-NMR and MS spectroscopic techniques. The crystal structure was characterized by X-ray syngle crystal analysis: orthorhombic, sp. gr. Pnna, Z = 4. In crystal packing, there are intramolecular hydrogen bond N-Ha <-O generating S(6) motif, and intermolecular hydrogen bond N-Ha <-S forming R (2) (2) (8) ring.Öğe Synthesis, Crystal Structure and Cyclic Voltammetric Behavior of N-aroyl-N?-(4?-cyanophenyl)thioureas(Mdpi, 2022) Aydin, Fatma; Arslan, N. BurcuHerein, two title compounds, N-benzoyl-N'-(4'-cyanophenyl)thiourea (1) and N-(4-nitrobenzoyl)-N'-(4'-cyanophenyl)thiourea (2) were synthesized in a high yield, via different applications of aroyl isocyanate and 4-aminobenzonitrile. The structure of the prepared compounds was characterized by elemental analysis and FT-IR, H-1, and C-13-NMR spectroscopic methods. The crystal structure of the title compound 1 was determined by an X-ray single-crystal technique and an intramolecular C=O center dot center dot center dot H-N hydrogen bond and intermolecular C=S center dot center dot center dot H-N and C=S center dot center dot center dot H-C hydrogen interactions, which were observed for the crystal structure. The molecular electrostatic potential (MEP) and the Mulliken atomic charges of title compounds 1 and 2 were theoretically calculated and interpreted. Cyclic voltammetric (CV) experiments for the compounds were performed with the glassy carbon electrode. The reduction in potential values of the different functional groups such as nitro and cyano in title compounds were investigated using CV curves.Öğe Synthesis, Spectral Properties, Crystal Structure and DFT Studies of 2,2'-diamino-4,4'-(propane-2,2'-diyl)-Diphenol(Springer/Plenum Publishers, 2023) Aydin, Fatma; Arslan, N. BurcuA bisphenol-A derivative, 2,2'-diamino-4,4'-(propane-2,2-diyl)-diphenol (3), was synthesized by nitration of bisphenol-A and then by its reduction. The title compound was characterized by elemental analysis, typical spectroscopic techniques, namely FT-IR, 1H-NMR, and 13C-NMR. The structure of the compound was also determined by single crystal X-ray diffraction method. The compound crystallized in the orthorhombic system with space group Pbcn and a = 15.51106(18) A, b = 11.6910 (10) A, c = 7.6473 (7) A. It is seen that the hydrogen atoms of the -OH groups are in trans-position to the NH2 groups in the crystal structure of the title compound. Moreover, it was observed in the dimeric lattice that the hydrogens of the -NH2 groups made intramolecular and those of the -OH groups intermolecular hydrogen bonds. The geometry of the compound was optimized by the DFT method and the results were compared with the X-ray diffraction data. Frontier molecular orbitals of the title compound were calculated by using the B3LYP/ 6-31G(d) method. MEP analysis and Mulliken charge density, Global reactivity and thermodynamic properties were also performed.Öğe Synthesis, spectral properties, crystal structure and theoretical calculations of a new geminal diamine: 2,2,2-Trichloro-N,N′-bis(2-nitrophenyl)-ethane-1,1-diamine(Elsevier B.V., 2021) Aydın, Fatma; Arslan, N. BurcuA new 2,2,2-trichloro-N,N׳-bis(2-nitrophenyl)-ethane-1,1-diamine was synthesized by the reaction of 2-nitroaniline in DCM with the chloral formed by distillation of chloral hydrate over concentrated H2SO4. The structure of the title compound was identified by means of FT-IR, 1H NMR, and 13C NMR spectroscopic techniques. The crystal structure of the title compound has also been examined by using X-ray crystallographic techniques and found to be crystallized in the monoclinic crystal system and space group P21/n with the unit cell parameters: a = 7.7075(12) Å, b = 7.7396(10) Å, c = 28.247(4) Å, β = 93.602(5)°, V = 1681.7(4) Å3, Dx = 1.602 Mg m − 3, and Z = 4 respectively. The calculated electronic structure properties of the title molecule such as HOMO-LUMO analysis, molecular electrostatic potential (MEP) map, and the Mulliken charge distributions were investigated by using the density functional theory (DFT) method. Theoretically calculated values exhibit the chemically hard, high kinetic stable and less reactive molecule.Öğe Synthesis, spectroscopic and structural characterisation of two p-nitrobenzamide compounds: experimental and DFT study(Taylor & Francis Ltd, 2015) Arslan, N. Burcu; Kazak, Canan; Aydin, FatmaThe title molecules, N-(1,5-dimethyl-3-oxo-2-phenyl-1H-3-(2H)-pyrazolyl)4-nitrobenzamide (C18H16N4O4 center dot H2O) (I) and 2,2-dimethyl-3-(4-nitrobenzoyl)-5-(phenylamino)-2,3-dihydro-1,3,4-thiyadiazole (C17H16N4O3S) (II), were prepared and characterised by H-1 NMR, C-13 NMR, infrared spectroscopy (IR) and structural X-ray diffraction (XRD) techniques. The molecular geometries, vibrational frequencies of the title compounds in the ground state have been calculated by using the density functional theory (DFT) method with 6-31G(d) basis set, and compared with the experimental data. The calculated results showed that the optimised geometries from the DFT method agree with the X-ray structures well for both compounds. Theoretical calculations of harmonic vibration frequencies are in good agreement with experimental results. To determine conformational flexibility, the molecular energy profiles of the title compounds were obtained. Besides, molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis and thermodynamic properties of the title compounds were investigated by theoretical calculations.Öğe Tautomerism in 4-chlorophenyl benzoylcarbamodithioate: Experimental and DFT study(Elsevier Science Bv, 2017) Aydin, Fatma; Arslan, N. Burcu; Ozdemir, NamikThe title dithiocarbamate compound was synthesized, and characterised by means of spectroscopic and single-crystal X-ray diffraction methods. Density functional theory method with the 6-311++G(d,p) basis set was employed to affirm the spectroscopic and structural properties and also to study the tautomerism in the compound. The obtained theoretical parameters clearly support the experimental findings. Among the six structural forms of the title compound, the syn-keto-amine-thione is found to be the most stable one, and the stability sequence is as the followings: syn-keto-amine-thione > anti-enolimine-thione > anti-keto-amine-thione > anti-keto-imine-thiol > syn-keto-imine-thiol > syn-enolimine-thione. The energy difference between the anti and syn forms changes from ca. 8-59 kJ morl(-1) with or without barriers. The energetic and thermodynamic findings of the syn-lceto-amine-thione reversible arrow syn-keto-irnine-thiol reaction display that the single proton exchange is unfavoured in both directions. Although the reverse barrier energy of the anti-enol-imine-thione reversible arrow anti-keto-imine-thiol tautomeric transformation is found to be small, neither the forward nor the reverse reaction appears to happen from the thermodynamic point of view. (C) 2017 Elsevier B.V. All rights reserved.
