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    Öğe
    Crystal structure, 1 H and 13C NMR spectral studies of 1,2,4,5-oxadiazaborole derivatives
    (2019) Pir, Meryem; Ağırbaş, Hikmet; Şahin, Onur
    Substituent effects on 1H and 13C NMR chemical shifts of 5-substituted phenyl3-phenyl-4,5-dihydro-1,2,4,5-oxadiazaboroles (1a-r) were studied respectively.Single and duel substituent parameters were used for the correlation analysis ofsubstituent-induced chemical shifts with σ, F and R constants. The calculationshave shown the polar and resonance substituent effects on N-H proton and C=Ncarbon atoms. The ρ value was found positive for compounds (1a-r), which meansthat the substituent effect is normal. Additionally, crystal structure of compound(1i) was also studied. Density functional theory (DFT) calculations were carriedout to calculate the theoretical chemical shifts, bond distances and bond angles.
  • [ X ]
    Öğe
    Crystal structure, 1H and13 C NMR spectral studies of 1,2,4,5-oxadiazaborole derivatives
    (Turkish Energy Nuclear and Mining Research Institute, 2019) Pir, Meryem; Ağırbaş, Hikmet; Şahin, Onur
    Substituent effects on 1H and 13C NMR chemical shifts of 5-substituted phenyl-3-phenyl-4,5-dihydro-1,2,4,5-oxadiazaboroles (1a-r) were studied respectively. Single and duel substituent parameters were used for the correlation analysis of substituent-induced chemical shifts with σ, F and R constants. The calculations have shown the polar and resonance substituent effects on N-H proton and C=N carbon atoms. The ρ value was found positive for compounds (1a-r), which means that the substituent effect is normal. Additionally, crystal structure of compound (1i) was also studied. Density functional theory (DFT) calculations were carried out to calculate the theoretical chemical shifts, bond distances and bond angles. © 2019, Turkish Energy Nuclear and Mining Research Institute. All rights reserved.
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    Öğe
    Synthesis, characterization, antimicrobial activity, and QSAR studies of some new 6-substituted phenyl 3-(4-chlorophenyl)-3a,4,8,8a-tetrahydro-[1,3,2]dioxaborepino [5,6-d]isoxazoles
    (Wiley-Hindawi, 2017) Pir, Meryem; Agirbas, Hikmet; Budak, Fatma; Sahin, Onur
    3-(4-Chlorophenyl)-3a,4,8,8a-tetrahydro-[1,3,2]dioxaborepino[5,6-d] isoxazoles were synthesized from the reaction of (3-(4-chlorophenyl)-4,5-dihydroisoxazole-4,5-diyl) dimethanol with substituted phenylboronic acids. Crystal structure of 1-(4-(3-(4-chlo rophenyl)-3a,4,8,8a-tetrahydro-[1,3,2]dioxaborepino[5,6-d] isoxazol-6-yl) phenyl) ethanone was studied and the values of selected bond distances (angstrom), bond angles (degrees), and dihedral angles (degrees) were found in agreement with the calculated (DFT, B3LYP/6-311++G(d,p)) values. Antimicrobial activity of these new compounds was also studied against a panel of microorganisms including Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Escherichia coli, Streptococcus mutans, and Candida albicans. Most of the dioxaborepines exhibited fair activities against these microorganisms. The pMIC values of the compounds were first correlated with Hammett polar substituent constant (sigma) together with lipophilic constant (pi) and statistically significant 2D correlations were obtained. In addition, the pMIC values of the compounds were correlated with some theoretical descriptors and fair 2D-QSAR models with clogP, SAA, and mu as independent variables were obtained.