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Öğe Preparation and spectroscopic studies of Fe(II), Ru(II), Pd(II) and Zn(II) complexes of Schiff base containing terephthalaldehyde and their transfer hydrogenation and Suzuki-Miyaura coupling reaction(Sciendo, 2019) Turan, Nevin; Buldurun, Kenan; Colak, Naki; Ozdemir, IsmailThis study describes synthesis, spectroscopic characterization and catalytic activities of Fe(II), Ru(II), Pd(II) and Zn(II) complexes with a novel Schiff base ligand (L) derived from methyl 2-amino-5,5,7,7-tetramethyl-4,5,6,7-tetrahydrobenzo[b] thiophene-3-carboxylate and terephthalaldehyde. We used spectroscopic techniques including IR, UV-Vis, H-1-NMR, C-13-NMR, elemental analysis and also mass analysis and magnetic susceptibility measurements to identify the products. The Pd(II) complex was used as a potential catalyst for Suzuki-Miyaura coupling reaction of some aryl halides under optimized conditions. The effect of various bases such as NaOH, KOH, and KOBut was investigated in transfer hydrogenation (TH) of ketones by isopropyl alcohol as the hydrogen source. Ru(II) and Pd(II) complexes showed catalytic activity while Zn(II) and Fe(II) metal complexes failed to do that.Öğe Preparation, spectral characterization, ESR measurements and DFT calculations of Schiff base copper(II) complex(Taylor & Francis Inc, 2021) Tokdemir Ozturk, Sibel; Aksu, Perihan; Turan, Nevin; Buldurun, Kenan; Tanis, Emine; Colak, NakiThe title compound ([CuClL(H2O)]center dot 2H(2)O) were synthesized. The copper(II) complex in square planar geometry were identified by using elemental analysis, magnetic susceptibility, mass spectra, FT-IR, UV-Vis. and ESR techniques. DFT calculations at the UB3LYP/LANL2DZ level of theory were conducted to obtain vibrational and electronic properties of the copper(II) complex. Vibrational assignments of the observed infrared spectra of title compound were carried out based on the calculated potential energy distributions (PEDs). The sensitive measurement results indicated that the observed values were reasonable. The energy values were determined to describe electronic properties of the title molecules. Furthermore, NBO analysis was performed to analyze the hyper-conjugative stability of the molecule, molecular orbital interaction and charge delocalization.Öğe Schiff Base and Its Fe(II), Zn(II), Ru(II), Pd(II) Complexes Containing ONS Donor Atoms: Synthesis, characterization and Catalytic Studies(2019) Buldurun, Kenan; Özek, Nevin Turan; Çolak, Naki; Özdemir, İsmailThe work include the synthesis, spectroscopic characterization and as well as catalytic activities of Fe(II), Zn(II), Ru(II), and Pd(II) complexes with a novel Schiff base ligand derived from methyl 2amino-5,5,7,7-tetramethyl-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate and salicylaldehyde. Spectroscopic techniques including IR, UV–Vis, NMR, and mass analysis as well as elemental analysis and magnetic susceptibility measurement were used to identify the compounds. Based on elemental and spectral studies octahedral geometry was proposed to Fe(II), Zn(II) and Ru(II) complexes and square planar geometry was proposed to Pd(II) complex. To improve more efficient and stable catalysts, we wanted to study if there is any influence the catalytic activity of ruthenium complex for the transfer hydrogenation of ketones and we wanted to examine the catalytic activities of palladium complex in Suzuki C-C cross coupling reactions under various conditions.Öğe Solvent effects on the electronic and optical properties of Ni(II), Zn(II), and Fe(II) complexes of a Schiff base derived from 5-bromo-2-hydroxybenzaldehyde(Sage Publications Ltd, 2021) Buldurun, Kenan; Tanis, Emine; Turan, Nevin; Colak, Naki; Cankaya, NevinIn this article, the electronic, optical, and charge transfer properties of a Schiff base ligand prepared using 5-bromo-2-hydroxybenzaldehyde and ethyl 6-acetyl-2-amino-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxylate (C19H19BrN2O4S) and its Fe(II) (C19H30BrN2O10SClFe), Ni(II) (C19H28BrN2O9SClNi), and Zn(II) (C19H28BrN2O9SClZn) complexes are described based on different solvents environments and supported by theoretical calculations. Theoretical calculations are carried out using density functional theory (DFT/UB3LYP/LANL2DZ). The optical densities, optical band gaps, and refractive indices of the ligand and its Fe(II), Ni(II), and Zn(II) complexes in different solvent environments are obtained. The reorganization energies are calculated to determine the charge transfer rate of the studied compounds using both experimental and theoretical data. These experimental and theoretical results show that the ligand and its metal complexes can be used for optoelectronic applications and charge transfer materials in organic light-emitting diode applications.Öğe Study of structure and spectral characteristics of the Zinc(II) and Copper(II) complexes with 5,5-dimethyl-2-(2-(3-nitrophenyl) hydrazono)cyclohexane-1,3-dione and their effects on optical properties and the developing of the energy band gap and ınvestigation of antibacterial activity(Sociedad Quimica de Mexico A.C., 2014) Turan, Nevin; Gündüz, Bayram; Körkoca, Hanifi; Adıgüzel, Ragıp; Çolak, Naki; Buldurun, KenanA new chelating ligand, 5,5-dimethyl-2-(2-(3-nitrophenyl) hydrazono)cyclohexane-1,3-dione (L), and four transition metal complexes were synthesized. The ligand and its complexes were characterized by IR, 1H and 13C-NMR spectra, elemental analyses, magnetic susceptibility, mass spectra, UV-Vis. and thermogravimetry-differential thermal analysis (TGA-DTA). The metal complexes showed different geometric structures. Antibacterial tests of the ligand and complexes were also done. The Zn(II) complexes showed antibacterial activity against Staphylococcus aureus ATCC-25923 at middle level. The optical properties of the ligand and its complexes were extensively investigated by optical measurements. The average transmittance value of the ligand was the highest value, while the average transmittance value of the [CuL2(NO3)2]·6H2O complex was the lowest value. The optical band gap of the ligand, [(Zn)2L(OH)4]·2DMF, [ZnL(NO3)2(H2O)2]·5H2O, [CuL2(OAc)]·OAc·3.5H2O and [CuL2(NO3)2]·6H2O complexes were calculated and 3.121 eV, 2.180 eV, 1.551 eV, 2.489 eV and 1.556 eV values were found, respectively. The complexes decreased the optical band gap of the ligand. The optical band gap value of the [ZnL(NO3)2(H2O)2]·5H2O complex is the lowest value. The optical band gap value of the ligand is the highest value. The complexes decrease the angle of incidence of the ligand, while complexes increase the angle of refraction of the ligand. The electric susceptibility of the ligand decreases with its complexes. © 2014, Sociedad Química de México.Öğe Synthesis and structures of Fe(II), Zn(II) and Pd(II) complexes with a schiff base derived from methyl 2-amino-6-methyl-4,5,6,7-tetrahydrothieno[2,3-c] pyridine-3-carboxylate and comparison of their optical constants for different solvents and molarities(American Scientific Publishers, 2017) Turan, Nevin; Buldurun, Kenan; Gündüz, Bayram; Çolak, NakiSchiff base derived from condensation of o-vanillin (3-methoxysalicylaldehyde) and methyl 2-amino-6-methyl- 4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxylate and its metal complexes are synthesized and characterized based on elemental analyses, IR, 1H NMR, 13C NMR, magnetic susceptibility, mass spectra, UV-vis and thermal analysis (TGA). Specifically the spectral measurements display the octahedral structures of Fe(II), Zn(II) complexes and square planar geometry of Pd(II) complex. Here, the effects on optical constants such as absorbance, molar extinction coefficient, mass extinction coefficients, transmittance, absorption band edge and optical band gap of Fe(II), Zn(II) and Pd(II) complexes of the different solvents (dichloromethane (DCM), acetone and ethyl alcohol (EtOH)) and molarities (0.498, 0.249 and 0.124 mM) are investigated by solution technique. Copyright © 2017 by American Scientific Publishers All rights reserved.Öğe Synthesis, characterization, and antimicrobial properties of a new ligand and its Pd(II), Ru(II), Fe(II), Co(II) complexes(Düzce Üniversitesi, 2018) Buldurun, Kenan; Turan, Nevin; Alan, Yusuf; Çolak, NakiSchiff bases and their complexes are versatile compounds synthesized from the condensation of an amino compound with carbonyl compounds and widely used for industrial purposes and also exhibit a broad range of biological activities including antifungal, antibacterial, antimalarial, antiproliferative, antiviral, and antipyretic properties. In this study, the complexes of (E)-2-(3,5-di-tert-butyl-2-hydroxybenzylideneamino)-6-methyl4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile (L) with Co(II), Fe(II), Pd(II) and Ru(II) were successfully prepared. Structures of Schiff base and its metal complexes obtained were confirmed by FT-IR, 1H-NMR, 13CNMR, UV–vis, magnetic susceptibility, mass spectroscopy and elemental analysis. Antimicrobial activity of the synthesized Schiff base and its metal complexes have been studied. When the antimicrobial activities of the compounds were examined, it was observed that the lowest activity was exhibited by the ligand, and the highest activity was exhibited by the Co(II) and Pd(II) complexes. None of our compounds were been found to exhibit antifungal activity.Öğe Synthesis, characterization, antioxidant, antimicrobial and DNA binding properties of ruthenium(II), cobalt(II) and nickel(II) complexes of Schiff base containing o-vanillin(Springer Netherlands, 2019) Turan, Nevin; Buldurun, Kenan; Alan, Yusuf; Savcı, Ahmet; Çolak, Naki; Mantarcı, AsımIn this study, the complex combinations of Ru(II), Co(II) and Ni(II) with Schiff base obtained through the condensation of (E)-methyl 2-amino-6-methyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxylate with 2-hydroxy-3-methoxybenzaldehyde (o-vanillin) were prepared. The characterization of newly developed complexes was implemented by IR, elemental analyses, magnetic susceptibility, mass spectra, UV–Vis and thermogravimetry/differential thermal analysis. The X-ray powder diffraction pattern of the complexes was also investigated. The geometries of the complexes were found to be octahedral. Furthermore, antioxidant, antimicrobial and pBR322 plasmid DNA cleavage activities were investigated. The antibacterial effects of the Co(II) complex on Gram-positive and Gram-negative bacteria were identified to be higher than those of ligand. The Ru(II) complex was found to have higher radical scavenging potential on 1,1-diphenyl-2-picryl-hydrazyl (DPPH·), superoxide anion (O 2 ? ), hydroxyl (OH) and 2,2?-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals, in comparison with ligand. The binding affinity of the Ni(II) complex was higher than that of ligand. © 2019, Springer Nature B.V.Öğe Synthesis, Characterization, Optical Transition and Dielectric Properties of the Schiff Base Ligand and Its Cobalt(II) and Palladium(II) Complexes(Springer, 2019) Buldurun, Kenan; Gündüz, Bayram; Turan, Nevin; Çolak, NakiIn this study, Co(II) and Pd(II) complexes of a Schiff base ligand, methyl-2-((5-bromo-2-hydroxybenzylidene)amino)-6-phenyl-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate (L), were prepared and characterized used through FT-IR, UV-Vis., microanalyses, magnetic susceptibility, H-1-NMR, C-13-NMR, mass and thermogravimetric analyses. Optical transition and band structure properties, extinction characteristics, refractive indices and ambient behaviors, dielectric and electric susceptibility characteristics of the ligand, Co(II) and Pd(II) complex compounds were investigated in detail. Moreover, the impacts of the two complexes on these parameters and features of the ligand were examined. The main finding of the study was that the Co(II) complex decreased the optical band gap of the ligand from 2.682 to 2.357 eV.Öğe Synthesis, characterization, powder X-ray diffraction analysis, thermal stability, antioxidant properties and enzyme inhibitions of M(II)-Schiff base ligand complexes(Taylor & Francis Inc, 2021) Buldurun, Kenan; Turan, Nevin; Bursal, Ercan; Aras, Abdulmelik; Mantarci, Asim; Colak, Naki; Gulcin, IlhamiThe Schiff base ligand ((E)-6-methyl-2-(2,3,4-trimethoxybenzylideneamino)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile) and its cobalt(II) and palladium(II) complexes were successfully prepared. The structure of the compounds was elucidated by various techniques (NMR, FT-IR, powder X-ray diffraction, microanalysis, TGA, magnetic susceptibility, mass spectrometry). The Pd(II) complex showed a square planar geometry and the Co(II) complex had an octahedral geometry. ABTS (2,2-azino-bis 3-ethylbenzothiazloine-6-sulphonic acid), DPPH (1,1-diphenyl-2-picrylhydrazyl), FRAP (ferric-reducing antioxidant power) and CUPRAC (cupric reducing antioxidant capacity)in vitromethods were applied to identify the antioxidant features of the synthesized compounds. In addition, glutathione S-transferase and acetyl/butyryl cholinesterase enzymes were examined for possible inhibition capacities of the complexes. According to the enzyme activity measurements, Ru(II) complex inhibited both GST and BChE enzymes, while Fe(II) complex inhibited only AChE enzyme. Furthermore, the antioxidant activities and enzyme inhibitions of the previously synthesized Fe(II) and Ru(II) complexes of the same ligand were examined to make a comparison of the metal complexes. Communicated by Ramaswamy H. SarmaÖğe SYNTHESIS, CHARACTERIZATION, THERMAL, X-RAY, AND DFT ANALYSES OF 6-TERT-BUTYL 3-ETHYL 2-[(3-METHOXY/5-BROMO)-2-HYDROXY AND (3-NITRO/3-METHOXY)BENZYLIDENEAMINO]- 4,5-DIHYDROTHIENO[2,3-C]PYRIDINE-3,6(7H)-DICARBOXYLATE(Pleiades Publishing Inc, 2021) Çolak, Naki; Karayel, Arzu; Buldurun, Kenan; Turan, NevinIn this work, 6-tert-butyl 3-ethyl 2-amino-4,5-dihydrothieno[2,3-c]pyridine-3,6(7H)-dicarboxylate is synthesized from starting tert-butyl 4-oxopiperidine-1-carboxylate, ethyl cyanomalonate, and sulfur, and then, coupled with same aromatic aldehyde affords the corresponding Schiff base compounds. These compounds (2a-d) are characterized using FTIR, H-1 and C-13 NMR spectroscopic methods. The crystal and molecular structure of (E)-6-tert-butyl 3-ethyl 2-((2-hydroxy-3-methoxybenzylidene)amino)-4,5-dihydrothieno[2,3-c]pyridine-3,6(7H)-dicarboxylate (2a) is characterized by the X-ray crystallographic analysis. Compound 2a crystallizes in the monoclinic space group P2(1)/c. The molecular and crystal structure is stabilized by two O-HMIDLINE HORIZONTAL ELLIPSISN and O-HMIDLINE HORIZONTAL ELLIPSISO intramolecular hydrogen bonds (OMIDLINE HORIZONTAL ELLIPSISN and OMIDLINE HORIZONTAL ELLIPSISO are 2.598(5) angstrom and 2.990(5) angstrom, respectively; O-HMIDLINE HORIZONTAL ELLIPSISN = 147 degrees and O-HMIDLINE HORIZONTAL ELLIPSISO = 134 degrees). According to DFT, compound 2d also shows the intramolecular hydrogen bonding, while there is no this type of interaction in compound 2b and 2c.Öğe Synthesis, structural characterization and biological activities of metal(II) complexes with Schiff bases derived from 5-bromosalicylaldehyde: Ru(II) complexes transfer hydrogenation(Elsevier B.V., 2019) Buldurun, Kenan; Turan, Nevin; Savcı, Ahmet; Çolak, NakiIn this study, two novel Schiff base ligands (L1 and L2) derived from condensation of methyl 2-amino-6-methyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxylate and methyl 2-amino-6-phenyl-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate, both starting matter with 5-bromo-salicylaldehyde, and their Zn(II) and Ni(II) metal complexes have been prepared using a molar ratio of ligand:metal as 1:1 except the Ru(II) complexes 1:0.5. The structures of the obtained ligands and their metal complexes were characterized by elemental analysis, FT-IR, 1H NMR, 13C NMR, UV–vis, thermal analysis methods, mass spectrometry, and magnetic susceptibility measurements. Antioxidant and antiradical activity of Schiff base ligands and their metal complexes were been evaluated in vitro tests. Antioxidant activities of metal complexes generally were more effectives than free Schiff bases. 1c and 2c were used as catalysts for the transfer hydrogenation (TH) of ketones. 1c, 2c complexes were found to be efficient catalyst for transfer hydrogenation reactions. © 2018 King Saud UniversityÖğe Synthesis, structural characterization and biological activity of novel cyclohexane-1,3-dione ligands and their metal complexes(MDPI AG, 2015) Turan, Nevin; Körkoca, Hanifi; Adıgüzel, Ragıp; Çolak, Naki; Buldurun, KenanSome new Zn(II) and Cu(II) complexes [Cu(L1)(OAc)2]·H2O, [Cu(L1)(NO3)H2O]·NO3·3.5H2O, [Zn(L1)(NO3)2]·4.5H2O, [Zn(L1)(OAc)2(H2O)2]·3H2O, [Cu2(L2)(OAc)4]·2H2O·2DMF, [Cu(L2)2]·2NO3·1.5DMF·H2O, [Zn(L2)2(NO3)2]·DMF and [Zn2(L2)(OAc)4(H2O)4]·5H2O; L1 = 2-[2-(2-methoxyphenyl)hydrazono]cyclohexane-1,3-dione and L2 = 2-[2-(3-nitrophenyl)hydrazono]cyclohexane-1,3-dione were synthesized and characterized by IR, 1H-NMR,13C-NMR and ultraviolet (UV-Vis.) spectroscopy, elemental analysis, magnetic susceptibility, mass spectrometry and thermogravimetrydifferential thermal analysis (TGA-DTA). The synthesized ligands and their complexes were tested for antibacterial activity against Escherichia coli ATCC 25922, Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, and Salmonella typhimurium CCM 583. Some of complexes showed medium-level antibacterial activity against the test bacteria compared with ampicillin. © 2015 by the authors; licensee MDPI, Basel, Switzerland.Öğe Transition metal complexes of a multidentate Schiff base ligand containing pyridine: synthesis, characterization, enzyme inhibitions, antioxidant properties, and molecular docking studies(Springer, 2021) Bursal, Ercan; Turkan, Fikret; Buldurun, Kenan; Turan, Nevin; Aras, Abdulmelik; colak, Naki; Yergeri, Mayur C.A series of Fe(II), Ni(II), and Pd(II) complexes were prepared with a novel Schiff base ligand containing pyridine moiety. The prepared compounds were characterized using FT-IR, H-1 and (13) C NMR, UV-Vis, powder XRD, thermogravimetric analysis, mass spectra, magnetic susceptibility, and elemental analysis. The coordination geometry of Fe(II) and Ni(II) complexes were octahedral, where Fe(II) and Ni(II) metal ions were coordinated by an oxygen atom of the carbonyl group, a nitrogen atom of the azomethine moiety, and a phenolic oxygen atom. The Pd(II) complex had square planar geometry. All of the synthesized compounds were tested for their biochemical properties, including enzyme inhibition and antioxidant activities. According to the in vitro DPPH and FRAP antioxidant methods, the Schiff base ligand and its Fe(II)/Pd(II) complexes showed close antioxidant activities against the standards (BHA, BHT, ascorbic acid, and alpha-tocopherol). Enzyme inhibitions of the metal complexes were investigated against glutathione S-transferase (GST), acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) enzymes. The best inhibition value (K-i) was observed for the Ni(II) complex against GST (2.63 +/- 0.04 mu M). Also, the Pd(II) complex showed the best inhibition value (10.17 +/- 1.88 mu M) against AChE. Molecular docking specified significant interactions at the active pockets of respective target enzymes. The Ni(II) complex exhibited good binding affinity against both BChE (- 9.0 kcal/mol and 9.36 +/- 2.03 mu M) and GST (- 7.0 kcal/mol and 2.63 +/- 0.04 mu M) enzymes. [GRAPHICS] .
