Yazar "Sayin, Ulku" seçeneğine göre listele
Listeleniyor 1 - 10 / 10
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Anticancer, antimicrobial, spectral, voltammetric and DFT studies with Cu(II) complexes of 2-hydroxy-5-methoxyacetophenone thiosemicarbazone and its N(4)-substituted derivatives(Elsevier Science Sa, 2017) Turkkan, Ercan; Sayin, Ulku; Erbilen, Nesibe; Pehlivanoglu, Suray; Erdogan, Gokce; Tasdemir, Halil Ugur; Saf, Ahmet OzgurNew copper complexes of 2-hydroxy-5-methoxyacetophenone thiosemicarbazone and its N(4)-substituted derivatives were synthesized and characterized by theoretical DFT studies and experimental UV-Vis, FT-IR, EPR spectral analysis, cyclic voltammetry, magnetic susceptibility and conductivity measurements. The DFT calculation results have been used to predict and interpret the experimental results. The geometric parameter G within the range of 7.61-7.86 for all complexes confirms the mononuclear nature of the complexes. The EPR, UV-Vis, DFT studies and obtained bonding parameters show that all the complexes have square planar geometry and their M-L bonds have strong ionic and some in-plane a-bond character. In addition, the experimental and DFT studies showed that HOMO and LUMO energy levels of the complexes may present good electron transporting properties. Also, the investigated Cu(II) complexes were tested for biological activity, proving both in vitro antibacterial and anticancer activity. The complexes exhibited antibacterial activity against Gram positive bacteria S. aureus while exhibiting no activities against gram negative bacteria E. toll and S. gallinarum. The f parameters obtained experimentally by EPR support the antimicrobial activity properties results of the complexes. The evaluations of potential anticancer activity of these complexes were carried out against highly metastatic MDA-MB-231 breast adenocarcinoma cell line by MTT assay. Our results suggest that all tested copper complexes have high cytotoxic effects with the range of 1.76-3.53 mu M IC50 values in vitro. These copper complexes could be considered as potential anticancer agents to counteract drug resistance of metastatic cancer cells. (C) 2016 Elsevier B.V. All rights reserved.Öğe Cytotoxic effects, microbiological analysis and inhibitory properties on carbonic anhydrase isozyme activities of 2-hydroxy-5-methoxyacetophenone thiosemicarbazone and its Cu(II), Co(II), Zn(II) and Mn(II) complexes(Springer, 2021) Ucar, Asuman; Findik, Mukerrem; Kuzu, Muslum; Pehlivanoglu, Suray; Sayin, Ulku; Sayin, Zafer; Akgemci, Emine GulerMetal complexes of thiosemicarbazones have been receiving considerable attention in biological applications such as antimicrobial and anticancer therapies. In this work, Co(II), Zn(II) and Mn(II) complexes of 2-hydroxy-5-methoxyacetophenone thiosemicarbazone (HMAT) were synthesized for the first time and characterized by EPR, FT-IR, NMR, UV-Vis spectroscopies, TG/DSC and elemental analysis. X-ray powder diffraction analysis was carried out for Zn(II) complex. HMAT and its Cu(II), Co(II), Zn(II) and Mn(II) complexes were tested as enzyme inhibitory agents. All compounds are effective inhibitor of cytosolic carbonic anhydrase I and II isoforms (hCA I and II) enzymes. IC(50)values of HMAT and its Cu(II), Co(II), Zn(II) and Mn(II) complexes were determined as 93.35, 324.46, 25.67, 1.06 and 22.36 mu M for CA I isozyme and 99.02, 86.64, 57.76, 10.34 and 36.48 mu M for CA II isozyme, respectively. The evaluation of potential cytotoxic effects of the compounds was performed against normal epithelial breast mammary gland CRL-4010, estrogen-positive low metastatic MCF-7 and triple negative highly metastatic MDA-MB-231 breast adenocarcinoma cell lines by MTT assay. The results showed that the tested metal complexes have high cytotoxic effects than their ligand molecule. In particular, the Cu(II) complex displayed preciously high cytotoxic properties different from the others. Given these facts, the Cu(II) complex could be debated as potential chemotherapeutic molecule against drug-resistant breast cancer cells. Minimum inhibitory concentrations of the compounds against the test organisms were also detected for the microbiological analysis.Öğe An electron paramagnetic resonance and density-functional theory study on the methyl isotropic hyperfine coupling constants in gamma-irradiated 2,6-di-tert-butyl-4-methylphenol(Taylor & Francis Ltd, 2013) Turkkan, Ercan; Dereli, Omer; Sayin, Ulku; Tapramaz, RecepSingle crystal of gammairradiated 2,6-di-tert-butyl-4-methylphenol (BHT) was investigated using an electron paramagnetic resonance (EPR) technique at different orientations in the magnetic field at room temperatures. Taking into consideration the chemical structure and the experimental spectra of the irradiated single crystal of BHT, we assumed that one phenoxyltype paramagnetic species was produced having an unpaired electron localized at the methyl fragment side of the phenyl ring. Depending on this assumption, one possible radical was modeled using the B3LYP/6-311+G(d) level of density-functional theory. EPR parameters were calculated for these modeled radical using the B3LYP/TZVP and B3LYP/EPR-III level. The averaged value of isotropic hydrogen hyperfine coupling constants of rotating methyl functional group of phenoxyl radical is calculated for the first time. Theoretically calculated values of the modeled radical are in reasonably good agreement with the experimental data determined from the spectra (differences in averaged coupling constant values smaller than 5%, and differences in isotropic g values fall into 1ppt).Öğe EPR study of gamma-irradiated 2-Bromo-4?-methoxyacetophenone single crystals(Taylor & Francis Ltd, 2016) Tasdemir, Halil Ugur; Turkkan, Ercan; Sayin, Ulku; Ozmen, AyhanThe gamma-irradiated single crystals of 2-Bromo-4'-methoxyacetophenone (2B4MA) were investigated using electron paramagnetic resonance (EPR) technique. Density-functional theory calculations were employed to investigate and identify the radicals that have been assumed to be formed upon irradiation of 2B4MA single crystals. The EPR spectra of 2B4MA were recorded at different orientations in the magnetic field at room temperature. Taking into account the chemical structure and experimental spectra of irradiated single crystal of 2B4MA, it was assumed that at least two different radicals were produced in the sample. Following this assumption, six possible radicals were modeled and EPR parameters were calculated by using the DFT, B3LYP/6-311+G(d), for the modeled radicals individually. The calculated hyperfine coupling constants and g-tensors were used as initial values for simulation studies. The three crystallographic axes on the simulated spectra were well matched with experimental spectra for the two modeled radicals. Thus, we identified the R1 type radical and R4 type radical as paramagnetic species produced in gamma-irradiated 2B4MA.Öğe ESR Characterization of Two Oxovanadium (IV) Schiff Base Complexes Derived from Tris(2-aminoethyl)amine(Taylor & Francis Inc, 2012) Sahin, Mustafa; Kocak, Nuriye; Sayin, Ulku; Yilmaz, MustafaThe compounds, C21H27N4O3(L-1) and C21H27N7(L-2), is a tripodal Schiff base that was obtained from the reaction of tris(2-aminoethyl)amine (tren) and furan-2-carbaldehyde and pyrole-2-carbaldehyde. The tripodal Schiff bases and their oxovanadium complexes have been characterized on the basis of the results of the elemental analysis, magnetic susceptibility measurements and spectroscopic studies FT-IR, H-1-NMR, UV-Vis, ESR, magnetic moment and thermal analysis (TGA). Job's method of continuous variation shows 3: 2 metal to ligand ratio.Öğe Experimental and theoretical research on -irradiated 7-methoxy-4-methylcoumarin powder through EPR and DFT methods(Taylor & Francis Ltd, 2018) Sarikaya, Ebru Karakas; Ates, Levent; Sayin, Ulku; Ozmen, Ayhan; Dereli, OmerIn this paper, the effects of gamma irradiation on 7-Methoxy-4-methylcoumarin (7M4MC) molecule, an essential coumarin derivative, which has an inherent variety of biological activities, therapeutic properties and industrial usage were examined. For this purpose, the sample was irradiated with Co-60-gamma ray source for about 100kGy total doses. Theoretical calculations were performed using GAUSSIAN03 program for the possible radicals that were modeled from two stable conformations with lowest energies. In order to get well-resolved spectra and to determine the radical identity experimentally, EPR spectra of the irradiated 7M4MC sample were recorded at several spectrometer conditions. By considering the molecular structure and EPR spectra, alkyl-type radical was assumed to be formed by gamma irradiation. To support the estimations, simulations were done using theoretical EPR parameters as an initial value. The experimental spectra were well matched with the sum of simulated spectra obtained from two same type modeled radicals of two different conformations. As a result of experimental estimations and theoretical calculations, radiation-induced radicals were identified as two neutral alkyl radicals, originated from two stable conformations.Öğe New copper(II) complex based-thiosemicarbazone and phenanthroline: DNA/BSA binding, antiproliferative activity, DFT and docking studies(Elsevier, 2023) Findik, Mukerrem; Turkkan, Ercan; Pehlivanoglu, Suray; Sayin, Ulku; Ceylan, Umit; Akgemci, Emine GulerA new copper(II) complex {Cu(HPP)}, bromo(1,10-phenanthroline)(triphenylphosphine)copper(I) with 2-hydroxy-5-methoxyacetophenone thiosemicarbazone (HMAT) was synthesized and characterized by experimental FT-IR, Raman, UV-vis, TGA and EPR spectral analysis. The Cu(HPP) was theoretically modeled using the B3LYP/VTZ method/basis set and the values of the spectroscopic parameters were calculated by the DFT method. The coordination geometry around the Cu(II) in the compound was predicted as an elongated octahedral. Spectroscopic investigations showed the intercalative binding mechanism of the Cu(HPP) with calf-thymus deoxyribonucleic acid (ct-DNA). Spectroscopic techniques were also used to evaluate the interaction of the Cu (HPP) with bovine serum albumin (BSA), which revealed that the Cu(HPP) could bind to BSA significantly. In addition, the molecular docking between the Cu(HPP) and BSA was investigated to support the bonding mechanism. Further, we studied the anticancer activity of the Cu(HPP) in drug resistant breast cancer cell line (MDA-MB-231), with a focus on the proliferative characteristics. Our findings emphasize that this newly synthetized complex has a significant cytotoxic effect on the cells and can be utilized as a candidate chemotherapeutic agent to effectively target breast cancer.Öğe Paramagnetic characterization and dosimetric properties of Airfix drug and its ingredients (Montelukast sodium, Sorbitol): An EPR and DFT study(Pergamon-Elsevier Science Ltd, 2022) Ece, Emel; Tasdemir, Halil Ugur; Biyik, Recep; Ozmen, Ayhan; Sayin, UlkuIn this study, radiation effect on an asthma drug Airfix and its ingredients (Montelukast sodium, Sorbitol) were analyzed by using EPR spectroscopy in the dose range of 10 Gy-30 kGy. The dependence of radiation-induced radicals on irradiation dose, temperature and time was investigated in detail. It has been determined that the radical observed predominantly in the Airfix structure originates from Sorbitol, and the characteristic features of this alkyl-type radical have been clearly defined using both experimental EPR and theoretical DFT methods. Dosimetric properties were investigated for all samples and it was suggested that Airfix drug and Sorbitol could be used as an EPR dosimeter through this radical agent which was determined to be very stable and sensitive to radiation. Moreover, it has been emphasized that other drugs containing Sorbitol excipient can also be used for dosimetric purposes in the dose range studied and even irradiation doses can be detected in case of radiation sterilization.Öğe Self-assembly of a new building block of {BMo12O40} with excellent catalytic activity for methylene blue(Pergamon-Elsevier Science Ltd, 2019) Findik, Mukerrem; Ucar, Asuman; Colak, Alper Tolga; Sahin, Onur; Bingol, Haluk; Sayin, Ulku; Kocak, NuriyeA novel organic-inorganic hybrid of 2,2'-bipyridyl (2,2'-bipy) linked covalently with the first inorganic framework based on boron-containing Keggin-type heteropolymolybdate anion [BMo12O40](5-) has been hydrothermally synthesized in aqueous solution. The crystal structure was fully characterized by elemental analyses, single crystal X-ray diffraction, Fourier-transform infrared spectrum (FT-IR), powder X-ray diffraction (XRD), Ultraviolet-visible spectroscopy (UV-Vis) and electron paramagnetic resonance (EPR) analysis. The catalytic performance of the synthesized catalyst was studied in degradation of methylene blue (MB) at ambient temperature. The catalyst exhibited excellent degradation against MB with a rate constant of 0.506/m, which was much higher than those by other polyoxometalate catalysts. Moreover, it was found to be easily separated from the reaction solution and recycled up to five times without significant loss of degradation activity. (C) 2019 Elsevier Ltd. All rights reserved.Öğe Synthesis of Carbazole-Substituted thiosemicarbazone and its Cu(II) Complex, DNA/Protein Binding, Cytotoxic, antiproliferative activities and molecular docking studies(Elsevier, 2023) Findik, Mukerrem; Kuzu, Burak; Pehlivanoglu, Suray; Kaya, Serdal; Sayin, Ulku; Akgemci, Emine Guler; Saf, Ahmet OzgurIn this study, 9-ethyl-3-carbazolecarboxaldehyde-4-ethyl-thiosemicarbazone (ECCAET) and its copper(II) com-plex (Cu(ECCAET)2) were firstly synthesized and characterized. DFT and EPR studies confirmed that the complex is mononuclear and has square planar geometry. The interaction of all synthesized compounds with calf thymus DNA (CT-DNA) was examined by absorption and fluorescent spectroscopy. The experimental results showed that Cu(ECCAET)2 interacts with DNA via an intercalative binding mode. The binding interactions of the complex with CT-DNA have been confirmed through viscosity measurements revealing that the complex interacts with DNA via intercalation. Furthermore, the protein binding ability of ECCAET and Cu(ECCAET)2 was investigated using BSA via electronic absorption spectral titration, fluorescence quenching, and synchronous fluorescence spectrum studies, which revealed that the Cu(ECCAET)2 strongly bound to BSA over the ligand. Molecular docking studies were also performed to support the bonding mechanism of ECCAET and Cu(ECCAET)2 with DNA and BSA. The biological activity studies of ECCAET and Cu(ECCAET)2 against cancer cells were also investigated. A panel of cancer cell lines, including A2780 human ovarian adenocarcinoma, MDA-MB-231 human triple-negative breast adenocarcinoma, and as a control non-cancerous L929 fibroblast cell lines were also used to test the compounds' anticancer activities. Cytotoxic and antiproliferative properties of Cu(ECCAET)2 were visibly higher than its ligand (ECCAET) for all tested cell lines. The Cu(ECCAET)2 had a distinctive biological effects on A2780, and MDA-MB-231 cells compared to non-cancerous cells. Within these results, Cu(ECCAET)2 was found a promising drug candidate against gynecologic cancer diseases.
