Cilt:61 Sayı:01 (2019)

Permanent URI for this collection

https://dspace.ankara.edu.tr/handle/20.500.12575/76582

Browse

Browsing Cilt:61 Sayı:01 (2019) by Issue Date

Filter results by year or month
Now showing 1 - 5 of 5
  • No Thumbnail Available
    Item
    Probıng The Structure-Corrosıon Inhıbıtıon Property Relatıonshıp Of Pyrrole Olıgomers Wıth Dft Calculatıons
    (Ankara Üniversitesi Fen Fakültesi, 2019-12-31) Gece, Gökhan; Bilgiç, Semra; Kimya; Fen Fakültesi
    Density functional theory (DFT) calculations on pyrrole oligomers were carried out at the B3LYP/6-311+G(d,p) level to search the relationship between the molecular structure and corrosion inhibition. The electronic properties such as the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) energy levels, energy gap (LUMO-HOMO) and dipole moment were computed. It was found that these electronic values can explain some features of the inhibition phenomena.
  • No Thumbnail Available
    Item
    Synthesıs And Characterızatıon Of Pure Sılıca Powder From A K-Feldspar Sılıcate Ore For Industrıal Value Addıtıon
    (Ankara Üniversitesi Fen Fakültesi, 2019-12-31) AYINLA, Kuranga İ.; BABA, Alafara A.; PADHY, Subrat Ku.; ADIO, Oseni; ODELEYE, Kehinde A.; TRIPATHY, Bankim Ch.; Other; Other
    Nigeria is one of the African countries endowed with abundant varieties of solid mineral resources. Despite huge mineral abundance in all States of the Federation, these resources to boost the country’s economy, aid industrialization and revenue generation has been far less utilized. Thus, the utilization of a Nigerian k-feldspar ore containing an admixture of orthoclase (KAlSiO8 : 96-740-9031), albite (AlSiO8 : 96-940-0741) and quartz (SiO2 : 96-900-9667) impurities to produce pure silica powder (PSP) was investigated using roast-leaching and co-precipitation method. During leaching, parameters such as leachant concentration, effect of particle size and reaction temperature on the synthesis yield were accordingly examined. At optimal leaching conditions (2.0 mol/L NaOH, 90°C), 87% of the initial 10g/L ore reacted within 120 minutes. The un-reacted product (~13.0%) analyzed by XRD was found to contain siliceous impurities which could serve as a valuable by-product for some defined industries. The leachate at optimal leaching was accordingly co-precipitated using concentrated H2SO4 to obtain pure silica powder (PSP) of industrial value.
  • No Thumbnail Available
    Item
    Determınatıon Of Absolute Confıguratıon Of 8,8,10,10tetrachloro-20,21-Dıhydro-18h,23h-6,12-Epıazeno-6λ5,8λ5,10λ5, 12λ5[1,3,2]Benzoxazaphosphonıno[2',3':8,9][1,3,5,7,9,2,4,6,8] Pentaazatetraphosphacycloundsyno[2,1-B][1,3,2] Benzoxazaphosphonıne Usıng X-Ray Crystallography
    (Ankara Üniversitesi Fen Fakültesi, 2019-12-31) Elmas, Gamze; Okumuş, Aytuğ; İsaoğlu, Satiye Sevim; Hökelek, Tuncer; Kılıç, Zeynel; Kimya; Fen Fakültesi
    The title compound, 8, 8, 10, 10-tetrachloro-20,21-dihydro-18H, 23H-6, 12epiazeno-6λ5, 8λ5, 10λ5, 12λ5-[1,3,2] benzoxazaphosphonino [2',3':8,9][1,3,5,7,9,2,4,6,8] pentaazatetraphosphacyclo undsyno [2,1-b] [1,3,2] benzoxazaphosphonine; C16H16Cl4N6O2P4, a cyclotetraphosphazene, has a tetrachloro-2, 4-spiro-ansa-spiro (tetrachloro-2,4-sas) architecture in which the bicyclic structure has consisted of eightmembered tetrameric N4P4 and seven-membered ansa (N1/P1/P1′/N4′/C8′/C8/N4) rings fused with a common PNP fragment. The asymmetric unit possesses one-half of the molecule. P1 and P1′ atoms are stereogenic centres. In addition, there is a mirror plane passing through the N3 and N1 atoms in the molecule, and therefore, this compound is in meso form (RS/SR). According to the checkcif result, it is found that the absolute configuration of P1 and/or P1′ phosphorus centers is RS, displaying that in the solid-state there is only one enantiomer in the unit cell. The space group is P bnm with cell parameters of a = 6.2692(2), b = 15.8111(3), c = 22.9393(4) Å.
  • No Thumbnail Available
    Item
    Dft Calculatıons Of Benzoısoxazole Derıvatıves
    (Ankara Üniversitesi Fen Fakültesi, 2019-12-31) Özen, Ezgi; Kalkan, Melike; Civcir, Pervin Ünal; Kimya; Fen Fakültesi
    In this work, we carried out theoretical calculations to determine the structureactivity relationship and the properties of two benzoisoxazole derivatives. For the quantum chemical calculations, the Density Functional Theory (DFT) with B3LYP (Becke threeparameter hybrid correlation functional combined with Lee–Yang–Parr correlation functional) and 6-311+G(d,p) basis set were employed both in the gas phase and in different solvents such as toluene, chloroform, THF, DCM, acetone, DMSO. The CPCM (conductorlike polarizable continuum) solvation model was also used to compute condensed-phase energies in solvent systems. The structural parameters (bond lengths, bond angles, and dihedral angles), energetics (the total energies, the zero-point vibrational energies, the frontier orbital energies (EHOMO, ELUMO), and the bandgap energies) and the spectroscopic characteristics (UV, IR, 1H-NMR, and 13C-NMR) of the target molecules were also determined. The results of the calculations were compared with experimental values for molecule 1, which exists in literature. The calculated geometries (bond length, bond angle and dihedral angle) were in a good agreement with the experimental data. In the case of IR frequencies, the scaled calculated frequencies agreed reasonably well with the experimental results. Moreover, there is a good correlation between experimental and calculated proton signals (R² = 0.9769) and carbon signals (R² = 0.9972) of molecule 1.
  • No Thumbnail Available
    Item
    Desıgnatıon Of Absolute Confıguratıon Of Multıhetereocyclıc 9,13-Dıchloro-22,22-Dıpyrrolıdıne-1-Yl1h,2h,13h,19h-9,13-(Epıazenophosphazeno)-9λ5,11λ5,13λ5-[1,3,5,2,4] Benzoxadıazadiphosphonıno[4',5':2,3][1,3,2]Dıazaphospholo[2,1-D] [1,3,5,2,4]Benzoxadıazadıphosphonıne By X-Ray Crystallographıc Data
    (Ankara Üniversitesi Fen Fakültesi, 2019-12-31) Elmas, Gamze; Okumuş, Aytuğ; İsaoğlu, Satiye Sevim; Hökelek, Tuncer; Kılıç, Zeynel; Kimya; Fen Fakültesi
    The title compound, 9,13-dichloro-22,22-dipyrrolidine-1-yl-1H,2H,13H,19H-9,13-(epiazenophosphazeno)-9λ5,11λ5,13λ5-1,3,5,2,4]benzoxadiazadiphosphonino [4',5':2,3][1,3,2]diazaphospholo[2,1-d][1,3,5,2,4]benzoxadiazadiphosphonine; 2(C24H32Cl2N8O2P4). 0.5 C6H12, a cyclotetraphosphazene derivative, has a geminaldipyrrolidino-2-trans-6-dichloro-ansa-spiro-ansa (gem-dipyrrolidino-2-trans-6-dichloroasa) structure in which the tricyclic parts are consisted of three eight-membered rings, containing a tetrameric N4P4 and two ansa rings. However, all these rings are not planar. The asymmetric unit contains two crystallographically independent molecules and one half of the cyclohexane solvent molecule. In both molecules, it is expected that two P (P1 and P3/P1′ and P3′) atoms are stereogenic centres. Both gem-dipyrrolidino-2-trans-6-dichloro-asa molecules have trans structures according to the Cl atoms, and they are in the racemic forms. Besides, it is found that the absolute configurations of P1, P3 and P1′, P3′ phosphorus centers are RR and SS, respectively. The title compound has P-1 space group, a Sohncke chiral space group, with the cell parameters of a = 9.6682(2), b = 13.8587(3), c = 24.0250(4) Å, � =105.249(2)°, � = 96.298(3)° and � = 98.367(3)°.