Yazar "Osmanoglu, Semsettin" seçeneğine göre listele

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    Conformational, IR, NMR, and EPR analysis of ifosfamide by density functional theory calculation
    (Springer Wien, 2017) Osmanoglu, Yunus Emre; Tokatli, Ahmet; Sutcu, Kerem; Osmanoglu, Semsettin; Ucun, Fatih
    The optimized molecular structure, vibrational frequencies, H-1 and C-13 NMR chemical shifts, and EPR hyperfine splittings of 3-(2-chloroethyl)-2-[(2-chloroethyl) amino] tetrahydro-2H-1,3,2-oxazaphosphorine-2-oxide (ifosfamide) have been investigated using density functional theory (B3LYP) method with 6-31+G(d, p) basis set for the first time. The calculated optimized geometric parameters (bond lengths and bond angles), vibrational frequencies, NMR chemical shifts, and EPR hyperfine splittings were seen to be in a well agreement with the corresponding experimental data. The experimentalEPRspectrumof themoleculewas recorded after c-irradiation. From the comparison of the calculated and experimental results the formed radical was attributed to a carbon atom-centered radical occurred upon the loss of a chlorine atom due to breakage of the weak C-Cl bonds. So we mentioned that the free electron is transferred to a carbon atom through intramolecular rearrangement while the molecular charge changes to neutral situation, giving NHC alpha H2C beta H2 radical.
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    Electron paramagnetic resonance and FT-IR spectroscopic studies of DL-2-aminoadipic acid and ammonium acetate powders
    (Taylor & Francis Ltd, 2014) Baskan, M. Halim; Aydin, Murat; Canakci, Dilek; Osmanoglu, Semsettin
    Exposure of powder forms of DL-2-aminoadipic acid and ammonium acetate to gamma radiation results in the formation of free radicals detected by the electron paramagnetic resonance spectroscopy at room temperature. In these compounds, the observed paramagnetic species were attributed to the HOOCCH2CH2CH2CHCOOH and CH2COONH4 radicals, respectively. The g values and the hyperfine coupling constants of the unpaired electron with the environmental protons were determined for these two radicals. In work, the observed paramagnetic species were found to be stable at room temperature for more than two months. Also, these compounds were characterised by FT-IR and UV-VIS. Their thermal stabilities were determined by TGA and DTA measurements. Thermal analyses were shown to be unstable of the HOOCCH2CH2CH2CH(NH2)COOH and CH3COONH4 against thermo-oxidative decomposition.
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    Electron paramagnetic resonance characterization of gamma irradiation damage centers in powder of L-(+)-tartaric acid, N-acetyl-L-alanine and 1-methyl-L-histidine
    (Taylor & Francis Ltd, 2010) Baskan, M. Halim; Aydin, Murat; Osmanoglu, Semsettin; Topkaya, Ramazan
    The electron paramagnetic resonance (EPR) of -irradiated powders of l-(+)-tartaric acid, N-acetyl-l-alanine and 1-methyl-l-histidine were investigated at room temperature. Radiation damage centers are attributed to HOOCCH(OH)C(OH)COOH, CH3CHCOOH and -CH2CHCOOH radicals. The spectra were computer-simulated. Hyperfine structure constants and g-values were determined for these three radicals. The unirradiated samples showed no EPR signal. Some spectroscopic properties and suggestions concerning the possible structure of the radicals are discussed in this paper.
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    Electron paramagnetic resonance of radiation damage of ?-irradiated diethylmalonic acid
    (Elsevier, 2008) Osmanoglu, Semsettin
    It has been found that gamma-irradiation produces the CH3CH2C(COOH)(2) and (CH3CH2)(2)CCOOH radicals in this compound and gamma-irradiation damage centers in (CH3CH2)(2)C(COOH)(2) single crystal has been investigated by electron paramagnetic resonance (EPR) spectroscopy at room temperature. The crystals of diethylmalonic acid have been investigated at 295 K and analyzed for different orientations of the crystal in the magnetic field. The hyperfine coupling constants of the four hydrogens of the two methylene groups were found to be not equivalent. The g factor and the hyperfine constants for H atoms, as 3.0 mT, 1.80 mT, 0.59 mT and g = 2.0032, were found to be nearly isotropic. These results were compared with the earlier studies in malonic acid and derivatives radicals and discussed. (C) 2007 Elsevier B.V. All rights reserved.
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    Electron paramagnetic resonance of some ?-irradiated amino acid derivatives
    (Walter De Gruyter Gmbh, 2006) Zincircioglu, S. Burhanedtin; Canoruc, Naime; Osmanoglu, Semsettin; Baskan, M. Halim; Dicle, I. Yesim; Aydin, Murat
    gamma-Irradiated powders of N-acetyl-L-arginine, N-alpha-carbamyl-L-arginine, N-glycyl-L-leucine and glycyl-L-alanine were investigated at room temperature by electron paramagnetic resonance. The observed species in N-acetyl-L-arginine and Na-carbamyl-L-arginine were attributed to the CH2CHNHCNHNH2 radical, and those in N-glycyl-L-leucine and glycyl-L-alanine powders to (CH3)(2)(CCH2 and CH3CHCOOH radicals.
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    EPR and FT-IR spectroscopic studies of L-lysine monohydrochloride and L-glutamic acid hydrochloride powders
    (Elsevier, 2011) Aydin, Murat; Kartal, Zeki; Osmanoglu, Semsettin; Baskan, M. Halim; Topkaya, Ramazan
    Powders of L-lysine monohydrochloride and L-glutamic acid hydrochloride were gamma irradiated and the induced free radicals were investigated at room temperature by electron magnetic resonance techniques. The observed species in these compounds were attributed to the H(2)NCH(2)CH(2)CH(2)CH(2)CHGOOH and HOOCCH2CH2CHCOOH radicals, respectively. In both radicals, the unpaired electron interacted with alpha-proton and beta-protons. Also, the FT-IR and thermal analyses of both compounds were investigated. The functional groups in the molecular structures of L-lysine monohydrochloride and L-glutamic acid hydrochloride were identified by FT-IR spectrometer. The TGA, DTA and DTG graphics were obtained to explain the thermal behavior of molecules. (C) 2011 Elsevier B.V. All rights reserved.
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    EPR of ?-irradiated single crystal of iminodiacetic acid
    (Taylor & Francis Ltd, 2008) Baskan, M. Halim; Aydin, Murat; Osmanoglu, Semsettin
    The electron paramagnetic resonance of gamma-irradiated single crystal of iminodiacetic acid, HN(CH2COOH)(2), has been observed and analyzed for different orientations of the crystal in the magnetic field. The radicals produced by gamma-irradiation have been investigated at room temperature. The radiation damage centers produced in the crystals were attributed to the HN<(C)over dot>HCH2(COOH)(2) radical. The g values and hyperfine coupling constants of the unpaired electron with the environmental alpha-proton, methylene protons, NH proton and N-14 nucleus were determined. The results were found to be in agreement with hyperfine coupling and are discussed.
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    Investigation of 60Co ?-irradiated L-(-) malic acid, N-methyl-DL-valine and L-glutamic acid ?-ethyl ester by electron paramagnetic resonance technique
    (Elsevier Science Bv, 2010) Baskan, M. Halim; Aydin, Murat; Osmanoglu, Semsettin
    The electron paramagnetic resonance spectra of gamma-irradiated L-(-) malic acid, N-methyl-DL-valine and L-glutamic acid gamma-ethyl ester powders have been investigation at room temperature. Radiation damage centres are attributed to HOOCCH2CHCOOH, (CH3)(2)CCH(NHCH3)COOH and C2H5OCOCH2CH2C(NH2)COOH radicals, respectively. The spectra have been computer simulated. The EPR parameters of the observed radicals have been determined and discussed. (C) 2010 Elsevier B.V. All rights reserved.
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    Properties of gamma induced radicals in single crystal of iminodiacetic acid hydrochloride
    (Elsevier Science Bv, 2018) Osmanoglu, Semsettin; Aydin, Murat
    The aim of this study is to investigate the paramagnetic species induced by gamma irradiation in single crystals of iminodiacetic acid hydrochloride, HN(CH2COOH)(2)center dot HCl, at room temperature by electron paramagnetic resonance technique, and to determine their magnetic properties. The observed species in iminodiacetic acid hydrochloride single crystals were attributed to the H2NCHCH2(COOH)(2)center dot Cl radical. The g values and hyperfine coupling constants of the unpaired electron with the environmental alpha-proton, methylene protons, the NH proton, and N-14 nucleus were determined. The EPR spectra of radical found to be remained unchanged for more than two months. The results were observed as being in good conformity with the existing literature data. (C) 2018 Elsevier B.V. All rights reserved.
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    Radiation damage produced in powder of ?-(methylamino)isobutyric acid, ?-aminoisobutyric acid methyl ester hydrochloride and diethylmalonic acid
    (Taylor & Francis Ltd, 2009) Baskan, M. Halim; Osmanoglu, Semsettin; Dicle, I. Yesim
    The electron paramagnetic resonance spectra of gamma-irradiated powders of alpha-(methylamino) isobutyric acid - CH(3)NHC(CH(3))(2)COOH, alpha-aminoisobutyric acid methyl ester hydrochloride - NH(2)(CH(3))(2)CCOOCH(3) HCl, and diethylmalonic acid - (CH(3)CH(2))(2)C(COOH)(2) have been investigated at room temperature. It has been found that gamma-irradiation produces the (CH(3))(2)(C) over dotCOOH radical in the first, the (CH(3))(2)(C) over dotCOOCH(3) radical in the second and the (CH(3)CH(2))(2)(C) over dot COOH radical in the third compound. The spectra were computer-simulated. The g values and the hyperfine coupling constants of the unpaired electron with the environmental methyl, methylene protons and OH proton were determined. The results were found to be in good agreement with the existing literature data and theoretical predictions.
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    Radiation damage produced in single crystal of iminodiacetic acid hydrobromide
    (Elsevier, 2010) Aydin, Murat; Osmanoglu, Semsettin; Baskan, M. Halim; Dicle, I. Yesim
    Single crystals of iminodiacetic acid hydrobromide, H2N(CH2COOH)(2)center dot Br, were gamma-irradiated and the formed paramagnetic species were investigated at room temperature and analyzed for different orientations of the crystal in the magnetic field by electron paramagnetic resonance technique. The observed species in iminodiacetic acid hydrobromide single crystals were attributed to the H2NCHCH2(COOH)(2)center dot Br radical. The g values and hyperfine coupling constants of the unpaired electron with the environmental alpha-proton, methylene protons, and one proton of the NH2, and N-14 nucleus were determined. The results were found to be in good agreement with the existing literature data. (C) 2010 Elsevier B.V. All rights reserved.
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    Radiation effect studies on some glycine derivatives in solid state
    (Taylor & Francis Ltd, 2017) Osmanoglu, Y. Emre; Sutcu, Kerem; Osmanoglu, Semsettin
    Five glycyl derivatives, glycyl-L-histidine, L-alanyl-glycine, glycine hydrochloride, gly-gly hydrochloride and, gly-gly-glycine in powder form were exposed to 20kGy doses of Co-60 gamma radiation to study the effects of ionizing radiation. In these compounds, the paramagnetic centers formed after irradiation were attributed to the RNHCHCO-OH, CH2CHNH, H2NCH2CO-OHHCl, NH2CHCONHCH2COOHHCl and HNCH2CO-OH radicals, respectively. The effect of gamma irradiation to the radical structures and time stability of the radicals were investigated by EPR spectroscopy. The spectra were computer simulated and the hyperfine coupling constants were determined.
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    Structure and behaviour of the free radicals generated in gamma irradiated amino acid and iminodiacetic acid derivatives
    (Pergamon-Elsevier Science Ltd, 2011) Osmanoglu, Semsettin; Aydin, Murat; Osmanoglu, Y. Emre; Dicle, I. Yesim; Baskan, M. Halim
    An EPR study has been carried out to investigate the structure and behaviour of the free radical formed gamma-irradiated L-alaninamide hydrochloride, DL-glutamic acid monohydrate and N-(2-carboxyethyl) iminodiacetic acid powders at room temperature. The observed paramagnetic species have been attributed to the CH3CHCONH2, HOOCCH2CH2CHCOOH and HOOCCH2CH2NCHCH2(COOH)(2) radicals, respectively. Some spectroscopic properties and suggestions concerning possible structure of the radicals were also discussed in this study. Published by Elsevier B.V.