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    Fluorogenic ferrocenyl Schiff base for Zn2+ and Cd2+ detection
    (Springer, 2017) Findik, Mukerrem; Ucar, Asuman; Bingol, Haluk; Guler, Ersin; Ozcan, Emine
    A novel sensor based on acetylferrocene-containing Schiff base (ASB) was synthesized by reaction of alpha-chloroacetylferrocene and N-(salicylidene)-l-valinmethylester. The structure of the compound was characterized by using elemental analysis and Fourier-transform infrared (FT-IR), H-1 nuclear magnetic resonance (NMR), and C-13 NMR spectroscopy. Its metal-cation-sensing properties were investigated spectrofluorometrically. ASB served as selective chemosensor for Zn2+ and Cd2+ towards alkali, alkaline-earth, and various heavy-metal ions. It showed significant fluorescence enhancement for Zn2+ and Cd2+ ions, stemming from C=N isomerization and chelation-enhanced fluorescence. The binding modes of the complexes were determined to have 1:1 complexation stoichiometry, and the binding constants were calculated as (6.93 +/- 0.25) x 10(6) M-1 for ASB center dot Zn (2+) and (7.49 +/- 0.18) x 10(5) M-1 for ASB center dot Cd (2+) using the nonlinear curve-fitting method.
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    Investigation of Obtaining Natural Humic Acid From Asphaltites Commonly Found in Sirnak-Uludere Region
    (Gazi Univ, 2022) Taskesen, Edip; Acar, Sukru; Arli, Fatih; Dumrul, Hakan; Ertugrul, Gorkem; Bulbul, Saban; Ozcan, Emine
    The physical and chemical properties of asphaltites found in significant amounts in Sirnak and its surroundings are close to coal. But it differs from coal because of its formation sources and chemical processes. Asphaltites were separated from the oil in liquid state by tectonism and settled in other locations, hardened by chemical reactions during geological processes and turned into solid phase. Most of the heating need in the Southeastern Anatolia Region is met by asphaltites. However, it is a raw material with low calorific value, high content of ash, sulfur and moisture, and high potential to adversely affect air pollution.It contains nitrogen and humic acid that dissolves slowly in aqueous media and can be used as soil reinforcement. In this study, researches were made to obtain natural humic acid from the content of asphaltite samples taken from the mine reserve in Uludere district. In the experiments made with samples, the effects of pH changes, temperature changes, changes in mixing times, precipitation in KOH and HCl solution were investigated towards optimal humic acid recovery efficiency. Accordingly, natural humic acid was obtained with the highest efficiency of 33.95% as a result of the studies conducted with temperature experiments from the sample of the Uludere region.
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    Organometallic chiral Schiff base for enantio-selective fluorescent recognition of methionine
    (Springer International Publishing Ag, 2017) Ucar, Asuman; Findik, Mukerrem; Bingol, Haluk; Guler, Ersin; Ozcan, Emine
    Herein, the synthesis and characterization of a novel chiral Schiff bases derived from ferrocene, coded as 3, have been reported. The sensing behavior of the synthesized compound has been examined towards the enantiomers of some amino acids (methionine, alanine, serine, histidine, and threonine) by spectrofluorimetric method. The fluorescence response of compound 3 showed noticeable enhancement upon addition of d-methionine compared to l-methionine and kept nearly linear correlation with the concentration of d-methionine. The value of enantiomeric fluorescence difference ratio (ef) has been determined to be 1.54 when d - and l- methionine amount is 100 times more than compound 3. The results showed that the compound 3 can be used as a sensor for enantio-selective recognition of d-methionine.
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    Synthesis of anti-4-phenoxyphenylaminoglyoxime and its some transition metal complexes: Spectral, DFT, electrochemical and anticancer activity studies
    (Elsevier, 2020) Findik, Mukerrem; Ucar, Asuman; Turkkan, Ercan; Pehlivanoglu, Suray; Ozcan, Emine
    anti-4-phenoxyphenylaminoglyoxime (LH2) was synthesized starting from 4-aminodiphenylether and anti-chloroglyoxime in absolute ethanol. Then, mononuclear complexes [Ni(II) and Cu(II)] of LH2 were synthesized with the metal:ligand ratio of 1:2. The LH2 and its complexes [Ni(LH)(2) and Cu(LH)(2)] were characterized by elemental analysis, FT-IR, Raman, UV-vis, thermogravimetric analysis (TGA), H-1 NMR, C-13 NMR, heteronuclear multiple bond correlation (HMBC) spectroscopy and theoretical DFT studies. Also, redox properties of the ligand and its complexes were investigated by cyclic voltammetry in DMSO solution at room temperature. Conformational space was scanned with molecular mechanic simulations and then the possible stable conformers of LH2 ligand were determined by B3LYP/6-311++G (d,p) level calculations. The Ni(LH)(2) and Cu(LH)(2) metal complexes were modeled theoretically using B3LYP/LanL2DZ level. The theoretical vibrational frequencies were calculated by using optimization calculation levels. The NMR parameters of LH2 ligand, Cu(LH)(2) and Ni(LH)(2) metal complexes were calculated at mPW1PW91/6-311 + G (2d,p) level. Theoretically calculated values were compared with the related experimental values. The DFT calculation results have been used to predict and interpret the molecular structures of LH2 ligand and its complexes. The geometry around nickel in Ni(LH)(2) and around cupper in Cu(LH)(2) complex are almost square planar. In addition, we evaluated the efficacy of LH2 ligand and its Ni(LH)(2) and Cu(LH)(2) complexes in the breast adenocarcinoma cell line (MCF7). Our data showed that the metal compounds affect positively the cytotoxic activity of the ligand (LH2). The metal complexes, especially Ni(LH)(2) complex, exhibited noteworthy biological activity against the viability of MCF7 cells. (C) 2020 Elsevier B.V. All rights reserved.