Researcher:
ILDIZ, GÜLCE ÖĞRÜÇ

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GÜLCE ÖĞRÜÇ

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ILDIZ

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Researcher Of Publications: search.filters.isAuthorOfPublication.ef7690fd-a4d2-4926-bd2c-fc64ea6f7542

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Now showing 1 - 10 of 85
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    PublicationOpen Access
    Structural Aspects of the Ortho Chloro- and Fluoro- Substituted Benzoic Acids: Implications on Chemical Properties
    (MDPI, 2020) ILDIZ, GÜLCE ÖĞRÜÇ; Fausto, Rui
    This article presents a detailed comprehensive investigation of the ortho fluoro- and chloro- substituted benzoic acids both, as isolated molecules and in the crystalline phase. Quantum chemical calculations performed within the density functional theory (DFT) formalism are used to investigate the potential energy landscapes of the molecules, taking into special consideration the effects of the interactions between the carboxylic group and the ortho halogen substituents, as well as the nature of these later on the structure and properties of the investigated systems. The structures of the relevant conformers of the molecules are discussed in comparative terms, and used to rationalize experimental data obtained for the compounds in the gas phase and isolated in low-temperature inert matrices. The UV-induced photofragmentation reactions of two of the compounds isolated in cryogenic inert matrices were studied as illustrative cases. The structures of the crystals reported previously in the literature are revisited and discussed also in a comparative basis. Particular emphasis is given to the analysis of the intermolecular interactions in the different crystals, using Hirshfeld surface analysis, the CE-B3LYP energy decomposition model and the HOMA index, and to their correlation with thermodynamic data.
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    Infrared Spectroscopy in Cryogenic Matrices
    (2015) ILDIZ, GÜLCE ÖĞRÜÇ; 107326
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    FT-IR spectroscopy and multivariate analysis as an auxiliary tool for diagnosis of mental disorders: Bipolar and schizophrenia cases
    (Pergamon-Elsevier Science Ltd, The Boulevard, Langford Lane, Kidlington, Oxford Ox5 1Gb, England, 2016-01-05) Arslan, M.; Ünsalan, Ozan; Araujo-Andrade, C.; Kurt, Ethan; Karatepe, Hasan Turan; Yılmaz, Ayberk; Bölükbaşı Yalçınkaya, Olcay; Herken, Hasan; ILDIZ, GÜLCE ÖĞRÜÇ; 107326; 106111; 242682; 175748; 123240
    In this study, a methodology based on Fourier-transform infrared spectroscopy and principal component analysis and partial least square methods is proposed for the analysis of blood plasma samples in order to identify spectral changes correlated with some biomarkers associated with schizophrenia and bipolarity. Our main goal was to use the spectral information for the calibration of statistical models to discriminate and classify blood plasma samples belonging to bipolar and schizophrenic patients. IR spectra of 30 samples of blood plasma obtained from each, bipolar and schizophrenic patients and healthy control group were collected. The results obtained from principal component analysis (PCA) show a clear discrimination between the bipolar (BP), schizophrenic (SZ) and control group' (CG) blood samples that also give possibility to identify three main regions that show the major differences correlated with both mental disorders (biomarkers). Furthermore, a model for the classification of the blood samples was calibrated using partial least square discriminant analysis (PLS-DA), allowing the correct classification of BP, SZ and CG samples. The results obtained applying this methodology suggest that it can be used as a complimentary diagnostic tool for the detection and discrimination of these mental diseases. (C) 2015 Elsevier B.V. All rights reserved.
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    Structural Aspects and Reactivity of 5-Methylhydantion
    (2018) Nogueira, Bernardo, A.; Canotilho, Joa; Eusebio, M. E. S.; Henriques, M. S. C.; Paixao, Antonia; Rui, Fausto; ILDIZ, GÜLCE ÖĞRÜÇ; 107326
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    Investigation of the Magnetocaloric Effect and the Critical Behavior of the Interacting Superparamagnetic Nanoparticles of La0.8Sr0.15Na0.05MnO3
    (Elsevier Science Sa, 2022) Tozri, A.; Alhalafi, Sh.; Alrowaili, Ziyad A.; Horchani, Mongi; Omri, Aref; Skini, R.; Ghorai, S.; Benali, A.; Costa, Benilde F. O.; ILDIZ, GÜLCE ÖĞRÜÇ
    We report on structural, magnetic properties of Na-doped La0.8Sr0.15Na0.05MnO3 (LSNMO) nanoparticles (NP) with size about 50 nm elaborated via sol-gel route. The chemical composition was verified using the energy dispersive X-ray analysis (EDAX) and by X-ray photoelectron spectroscopy (XPS). Magnetic characterizations demonstrate that LSMNO exhibits a coexistence of interacting superparamagnetic (ISPM) phase with blocking temperature T-B = 194 K and a ferromagnetic phase with Curie temperature T-C = 255.5 K. At low temperatures, the SPM state undergoes a collective freezing state at T-f = 46 K. the high-temperature regime (well above TC) reveals that NP-LSNMO has a strengthened Griffiths-like phase compared to their bulk counterpart. An itemized investigation of the critical behavior of the material was carried out in the vicinity of T-C. The critical exponents [beta = 0.546(7), gamma = 0.972(6), and delta = 2.94 (5)] were found to be in close agreement with of the mean-field theory. The maximum magnetic entropy change (-Delta(pk)(M)) is about 1.41 Jkg(-1) K-1 and the refrigeration capacity (RC) is 288 Jkg(-1) for a field change of 5 T at T = 215 K. This magnetocaloric response is reasonably high for nanomaterials and, together with its cost-effectiveness, makes NP LSMNO a potential candidate material for active magnetic refrigerators. Besides, the ISPM properties are desirable for hyperthermia applications. Our findings suggest that the magnetic inhomogeneity and the dipolar interaction between the SPM and FM phases in the range T-B < T < T-C are crucial factors in determining the magnetic properties of NP-LSNMO. (C) 2021 Elsevier B.V. All rights reserved.
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    Structure, spectroscopic properties and catalytic activity for epoxide ring-opening of nickel methylxanthate
    (Elsevier, 2018-09) Kumar, Girijesh; Kumar, Rakesh; Fausto, Rui; Husain, Ahmad; ILDIZ, GÜLCE ÖĞRÜÇ; 107326
    The structure and spectroscopic properties of nickel methylxanthate, Ni(S2COCH3)2, as isolated molecule and in crystalline phase, were investigated both experimentally and theoretically. Experimentally, single crystal X-ray diffraction, infrared and ultraviolet–visible spectroscopies have been used, while the applied theoretical approaches include density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. The isolated molecule of the complex under study was found to exist in two nearly degenerated conformers (cis and trans, with the methyl groups of the ligand molecules positioned the same side or in opposite sides of the molecule, respectively). The trans conformer is selected upon crystallization. The crystal structure (at 100 K) was solved and discussed, with emphasis given to the characterization of the main intermolecular interactions. The infrared spectrum (in the 3500-300 cm−1 range) of the crystalline material was assigned in details, also taking into account the results of the normal coordinate analysis performed for the isolated molecule, which in turn was made using the data resulting from the DFT calculations. The UV–visible spectrum of the compound in CHCl3 solution was also obtained and interpreted based on results of TD-DFT calculations, demonstrating the importance of the metal to ligand charge transfer in the studied complex. Finally, the catalytic activity of the complex for ring-opening reaction of styrene oxide resulting from nucleophilic attack of anilines was also evaluated, showing that the compound presents potential as catalyzer of this type of reactions.
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    5-Methylhydantoin: Structure, Spectroscopy, Photochemistry and Polymorphism
    (2017) Nogueira, Bernardo, A.; Canotilho, Joa; Eusebio, M. E. S.; Henriques, M. S. C.; Paixao, Antonia; Rui, Fausto; ILDIZ, GÜLCE ÖĞRÜÇ; 107326
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    1-Methylhydantoin: From the Matrix Isolated Single Molecule to H-Bond Patterns Defining Different Polymorphs of the Compound
    (2017) Nogueira, Bernardo, A.; Canotilho, Joa; Eusebio, M. E. S.; Paixao, Antonia; Rui, Fausto; ILDIZ, GÜLCE ÖĞRÜÇ; 107326
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    From the Isolated Molecule to the Crystal: A Study of Isomerism, Photochemistry and Polymorphism in Hydantoin Derivatives
    (2017) Nogueira, Bernardo, A.; Canotilho, Joa; Henriques, M. S. C.; Eusebio, M. E. S.; Rui, Fausto; ILDIZ, GÜLCE ÖĞRÜÇ; 107326
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    Near-infrared in situ generation of the higher-energy trans conformer of tribromoacetic acid: Observation of a large-scale matrix-site changing mediated by conformational conversion
    (Amer Inst Physics, 1305 Walt Whitman Rd, Ste 300, Melville, Ny 11747-4501 USA, 2018-01-28) Apostolo, Rui F. G.; Bazso, Gabor; Tarczay, Gyorgy; Fausto, Rui; ILDIZ, GÜLCE ÖĞRÜÇ; 107326
    The first observation of the higher-energy conformer of tribromoacetic acid (trans-TBAA) is reported. The conformer was produced in cryogenic matrices (Ar, Kr, and N-2) by in situ selective narrowband near-infrared excitation of the lower-energy cis-TBAA conformer and characterized both structurally and vibrationally. The novel trans-TBAA conformer is shown to spontaneously decay to the most stable cis-TBAA form in all studied matrix media, by tunneling, and the measured decay rates in the different matrices were compared with those of the trans conformers of other carboxylic acids in similar experimental conditions. In the N-2 matrix, where trans-TBAA establishes a specific stabilizing intermolecular interaction with the host N-2 molecules via its OH group and is about 11 times more stable than in rare gas matrices, the effect of changing the irradiation wavenumber within the 2 nu OH absorption profile was investigated in detail. An interesting phenomenon of matrix-site changing mediated by conformational conversion was observed in the N-2 matrix: vibrational excitation of cis-TBAA in the 2 nu OH wavenumber range predominantly converts the molecules located in a specific "matrix site" into trans-TBAA; then, relaxation (by tunneling) of the produced higher-energy conformer back to the cis form populates almost exclusively another "matrix site." The experimental studies received support from quantum chemistry calculations, which allowed a detailed characterization of the relevant regions of the potential energy surface of the molecule and the detailed assignment of the infrared spectra of the two conformers in the various matrices. Published by AIP Publishing.