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Öğe 1,1?-(Piperazine-1,4-diyl)dipropan-2-ol(Int Union Crystallography, 2011) Turkyilmaz, Murat; Baran, Yakup; Ozdemir, NamikThe asymmetric unit of the crystal contains one-fourth of the title compound, C10H22N2O2, with the centre of the piperazine ring located at a site of 2/m symmetry. The piperazine ring adopts a chair conformation. The methine and methylene C atoms of the 2-hydroxypropyl groups show symmetry-imposed disorder over two equally occupied and mutually exclusive sets of positions. Only intramolecular O-H center dot center dot center dot N contacts are observed.Öğe 2-[2-(1H-Imidazol-3-ium-5-yl)ethyl]-3-(pyridin-2-yl)-2H-imidazo[1,5-a]pyridin-4-ium bis(perchlorate)(Int Union Crystallography, 2011) Turkyilmaz, Murat; Baran, Yakup; Ozdemir, NamikIn the title molecular salt, C17H17N5+center dot 2ClO(4), the dihedral angles between the fused-ring system and the pendant five- and six-membered heterocyclic rings are 6.4 (2) and 41.29 (19)degrees, respectively. The O atoms of both perchlorate anions are disordered over two sets of sites with occupancy ratios of 0.614 (8):0.386 (8) and 0.591 (7):0.409 (7). An intramolecular C-H center dot center dot center dot N contact occurs in the cation. In the crystal, the components are linked by N-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds and pi-pi stacking interactions [centroid-centroid separation = 3.642 (3) angstrom].Öğe Öğe Complexation of some pendant arm tetraazamacrocyles of Cu(II) and Co(II): Structural, thermodynamic and kinetic studies(Amer Chemical Soc, 2009) Baran, Yakup; Özay, Hava; Aktaş, Nahit; Miyamae, Hiroshi; Şahiner, NurettinÖğe Copper and cobalt complexes of octadentate azamacrocycles: Spectrophotometric titration, stopped-flow kinetics and crystallographic study(2011) Ozay, Hava; Baran, Yakup; Ishii, YouichiDetails of complex formation kinetics are reported for tetrakis(2- hydroxyethyl) substituted cyclen (L 1) and cyclam (L 2) with Cu(II) and Co(II). Stopped-flow kinetics and spectroscopic titration methods were employed for the activation parameters and stability constants, respectively. X-ray studies revealed that the pendant 2-hydroxyethyl groups are not equivalent: two are folded over the macrocycle and maintained by intramolecular hydrogen bonds while the others are extended and pointed away from the macrocyclic cavity. Complex formation kinetics and spectroscopic titration were performed in aqueous acidic buffer solutions. Thermodynamic and kinetic parameters revealed that the ring size of the macrocycles plays an extremely important role for each metal ion studied. Stopped-flow kinetic measurements explained the mechanism of the complex formation process of both Cu(II) and Co(II) which proceed in outer-sphere interactions with ligands. There are two steps in the complex formation of the system studied. The initial step is a second order reaction between the metal ion and macrocycle with a second order rate constant. © 2011 Elsevier B.V.Öğe Hydrogel networks for metal nanoparticle syntheses and their applications in catalysis(Amer Chemical Soc, 2009) Özay, Hava; Aktaş, Nahit; Baran, Yakup; John, Vijay T.; Şahiner, NurettinÖğe Magnetic hydrogel syntheses and their applications in the environment for the removal of toxic metal ions(Amer Chemical Soc, 2009) Özay, Özgür; Önder, Alper; Şahan, Tekin; Aktaş, Nahit; Baran, Yakup; John, Vijay T.; Şahiner, Nurettin[Anstract Not Available]Öğe PMSE 489-Poly(4-vinylpyridine) based nanoparticle syntheses and their applications to functional materials(Amer Chemical Soc, 2008) Özay, Özgür; Aydin, Fatma; Ekici, Sema; Yıldız, Mustafa; Baran, Yakup; Tan, Grace; John, Vijay T.[Anstract Not Available]Öğe Removal of toxic metal ions with magnetic hydrogels(Pergamon-Elsevier Science Ltd, 2009) Özay, Özgür; Ekici, Sema; Baran, Yakup; Aktaş, Nahit; Şahiner, NurettinHydrogels, based on 2-acrylamido-2-methyl-1-propansulfonic acid (AMPS) were synthesized via photopolymerization technique and used for the preparation of magnetic responsive composite hydrogels. These composite hydrogels with magnetic properties were further utilized for the removal of toxic metal ions such as Cd(II), Co(II), Fe(II), Pb(II), Ni(II), Cu(II) and Cr(III) from aqueous environments. It was revealed that hydrogel networks with magnetic properties can effectively be utilized in the removal of pollutants. The results verified that magnetic iron particle containing p(AMPS) hydrogel networks provide advantageous over conventional techniques. Langmuir and Freundlich adsorption isotherms were applied for toxic metal removal and both isotherms were fit reasonably well for the metal ion absorptions. (c) 2009 Elsevier Ltd. All rights reserved.Öğe Spectroscopic and structural properties of N-(acetamide) morpholinium bromide(Pergamon-Elsevier Science Ltd, 2011) Baran, Yakup; Ozay, Hava; Esener, Hasan; Turkyilmaz, MuratA new crystal of N-(acetamide) morpholinium (NAM) bromide has been prepared in methanol at room temperature and characterized by single crystal X-ray analysis, elemental analysis, GS-MS, FUR, NMR((1)H, (13)C, DEPTH and HETCOR). The N-(acetamide) morpholinium crystallizes in the orthorhombic crystal system, Pnma with unit cell a = 12.798(9) angstrom, b = 7.222(5) angstrom, c = 9.244(5) angstrom, beta = 90.00, V = 854.4(9) angstrom(3), Z = 4. The X-ray structure determination revealed that there are strong inner and intermolecular hydrogen bonds in the crystal. (C) 2011 Elsevier B.V. All rights reserved.Öğe Stability Constants of Some Polydentate Ligands with Nickel(II) by Spectrophotometric Titration(Chinese Chemical Soc, 2012) Ozay, Hava; Ulgen, Ahmet; Baran, YakupThe polydentate macrocyclic ligands, 1,4,7,10-tetraazacyclododecane (L-1), 1,4,8,11-tetra (2-hydroxyethyl)-1,4,8,11-tetraazacyclotetradecane (L-2); and acyclicpolydentate ligands; 3-(2-aminocyclohexylamino)-2-(2-aminocyclohexylaminomethyl) propionic acid (L-3), 4,7,10-triazatridecane dinitrile trihydrochloride (L-4), 2, 2'-(1,2-diyl)bis(methylazanediyl)diethanol (L-5) and 1,1'-(ethane-1,2-diylbis((2-aminoethyl) azanediyl)) dipropan -2-ol, (L-6) were prepared and their structures were investigated by FTIR, NMR and MS. The stability constants of the nickel (II) complexes with these ligands were determined by spectrophotometric titration using a diode array UV-VIS spectrophotometer equipped with peristaltic pump and pH meter. The values of the stability constants are discussed in terms of the open chain or cyclic nature of the ligands. The effect of pendant group on the stability of the complexes is discussed.Öğe Structure, spectroscopic, magnetic, fluorescence, and thermal studies of bis(perchlorate)tetrakis(pyrazole)copper(II)(2011) Baran, Yakup; Esener, Hasan; Turkyilmaz, MuratThe complex bis(perchlorate)tetrakis(pyrazole)copper(II) has been prepared and characterized by single crystal X-ray analysis, FT-IR, UV-VIS spectroscopy and thermal methods. [Cu(ClO4)2(pyzl)4] crystallizes in the monoclinic system, space group C2/c, with a = 14.5186(11), b = 9.9513(7), c = 15.8564(11) Å, ? = 115.5290(10)° V = 2067.2(3) Å3 and z = 4. The molecular and crystal structure are stabilized by inter and intra molecular hydrogen bonds. The complex formation kinetics was studied at 310 nm. The activation parameters of the complex formation kinetics were determined as, ?H#: 200 kJ/mol, ?S#: 268 J/K. mol. The FT-IR spectra has been measured and assigned in the range of 4000-400 cm-1. The Cl-O and N-H stretching vibrations confirms the presence of intramolecular hydrogen bonds. The magnetic moment of the complex was found to be 1.73 BM. The fluorescence quenching of pyrazole by Copper(II) was also studied in methanol. Copyright © Taylor & Francis Group, LLC.Öğe Structure, spectroscopic, thermal properties and catalytic activity of iron(III)-Schiff base complexes(Elsevier Science Sa, 2013) Turkyilmaz, Murat; Kacan, Mesut; Baran, YakupIron(III) complexes of the Schiff bases: [FeLCl3] (L = 3-(1H-imidazole-1-yl)-N-[(1E)-1H-pyrrol-2-ylmethylene]propan-1-amine, L-1; 3-(1H-imidazole-1-yl)-N-[(1E)-(3-methyl-2-thienyl)methylene]propan-1-amine, L-2; 1-(3-{[(1E)-1H-pyrrol-ylmethylene]amino} propyl)pyrrolidin-2-one, L-3; 1-(3-{[(1E)-2-furylmethylene] amino} propyl) pyrrolidin-2-one, L-4 have been prepared and characterized by NMR, Mass, FTIR, UV-Vis spectroscopy, elemental analysis, conductance in non-aqueous solvent, and magnetic measurements. The analytical data showed that the Schiff bases act as tridentate ligands towards trivalent iron via azomethine, imidazole, pyrrole, pyrrolidin nitrogen, furan oxygen and thiophene sulfur. Thermal characterizations of the complexes have been studied in nitrogen atmosphere by simultaneous thermogravimetry and differential thermal analysis, TG-DTA. Two-step decompositions were observed until 800 degrees C by TG-DTA, involving first release of water until 200 degrees C. Finally, the organic portion of the complex was burnt out slowly accompanied by a sharp endothermic heat effect; meanwhile iron oxide is formed rapidly. The results suggested that the azomethines are tridentating chelates by N-3, N2S and N2O donor atoms. A high spin octahedral geometry is assigned to the Iron(III) ion in all four complexes. It has been found that iron(III)- Schiff base complexes activate the epoxidation of cis-1,2-diphenylethylene by NaOCl. The epoxide conversion cis-1, 2-diphenylethylene and the ratio of the cis:trans epoxides vary depending on the structure of the Schiff bases. (c) 2012 Elsevier B.V. All rights reserved.Öğe Syntheses, Spectroscopic, and Thermal Characterization of Cu(II), Ni(II), and Pt(II) Complexes of Some Tridentate Ligands(Taylor & Francis Inc, 2013) Turkyilmaz, Murat; Karabulut, Ferhat; Altun, Ozlen; Baran, YakupThe study emphasized azomethine coordination compounds of Pt(II), Cu(II), and Ni(II) having tetracoordinate geometry around the metal ions with the general formula, [MLCl]Cl, where L, azomethine have been isolated in the solid state. All the ligands were identified by spectroscopic methods and elemental analysis. The synthesized coordination compounds have been characterized by FTIR, magnetic measurements, elemental analysis, electrical conductance, and thermal analysis. Square planar structures have been proposed for the Ni(II) and Pt(II) complexes. Magnetic susceptibility measurements and electronic spectra of the complexes sustain the proposed square planer structures. The complexes thermally stable and this thermal stability is discussed in terms of ligands donor atoms, geometry and central metal ions. Azomethine complexes have a similar thermal behavior for the selected metal ions. The TG analyses suggest high thermal stability for most complexes followed by thermal decomposition in different steps. The decomposition processes were observed as water elimination, chloride anion removal, and degradation of the organic ligands. Supplemental materials are available for this article. Go to the publisher's online edition of Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry to view the supplemental file.Öğe Synthesis, complex formation kinetics and thermodynamic study of some acyclic polyamine and N2O2 ligands with copper(II)(Taylor & Francis Ltd, 2010) Ozay, Hava; Baran, YakupThe polydentate ligands, 3-(2-aminocyclohexylamino)-2-(2-aminocyclohexyl aminomethyl) propionic acid (L1), 4,7,10-triazatridecanedinitrile trihydrochloride (L2), and 2,2'-(ethane-1,2-diyl) bis(methylazanediyl) diethanol (L3) were prepared and their structures investigated by FT-IR, NMR, and MS. The kinetics of complex formation between Cu(II) and L1, L2, and L3 were investigated in acidic aqueous solutions using the stopped-flow method. The stability constants of the complexes were determined by spectrophotometric titration (T = 293 K, = 0.1 mol L-1 NaClO4), using a diode array UV-Vis spectrophotometer equipped with peristaltic pump and pH meter. The stability constants for the complexes were CuL1 CuL2 CuL3. Activation enthalpies (H#) of these complexes were 55 kJ mol-1 for CuL1, 61 kJ mol-1 for CuL2, and 36 kJ mol-1 for CuL3, respectively.Öğe Synthesis, spectroscopic and thermal properties of Pt(II) complexes of some polydentate ligands(Springer, 2012) Baran, Yakup; Kaya, İsmet; Türkyılmaz, MuratThe new tetradentate symmetrical (2R, 2'S)1,1'-piperazine-1,4-diyldipropane-2-thiol) (L-1), (2S)-1-[bis (2-aminoethyl) amino] propan-2-ol) (L-2), and 2-{(E)-[((1R, 2S)-2-{[(1Z)-(2-hydroxy phenyl)methylene]amino}cyclohexyl) imino] methyl} phenol (L-3) ligands were synthesized and characterized on the basis of FT-IR, H-1, C-13 NMR, EI mass, and elemental analysis. Three commercially available ligands, (2,2'-[ethane-1,2-diylbis(thio)] diethanol (L-4), 2,2'-dithiodiethanenamine (L-5), and (2,2-[ethane-1,2-diyldi(imino)] diethanol (L-6), were also studied. Pt(II) complexes were characterized by FTIR, elemental analysis and thermal methods. Thermal behaviors of these complexes were investigated in the range 10-1000 degrees C. Magnetic properties were also studied, and the all complexes were found to be diamagnetic. The structures consist of the monomeric units in which the Pt(II) atoms exhibit square planar geometry. N,N'-bis(salicylidene)-1,2-cyclohexane has been synthesized and characterized by X-ray single crystal diffraction measurement. The ligand crystallizes in monoclinic crystal system and space group, Cc.Öğe Synthesis, spectroscopic characterization, X-ray structure and DFT studies on 4-(2-hydroxyphenyl)-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridin-5-ium chloride hydrate(Pergamon-Elsevier Science Ltd, 2011) Turkyilmaz, Murat; Ozdemir, Namik; Baran, YakupThe title molecular salt, 4-(2-hydroxyphenyl)-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridin-5-ium chloride hydrate (C12H14N3O+.Cl-.H2O), was synthesized and characterized by IR-NMR spectroscopy and single-crystal X-ray diffraction. In addition to the molecular geometry from X-ray experiment, the molecular geometry, vibrational frequencies and gauge-independent atomic orbital (GIAO) H-1 and C-13 NMR chemical shift values of the title compound in the ground state have been calculated using the density functional theory (DFT/B3LYP) method with the 6-31++G(d,p) and 6-311++G(d,p) basis sets, and compared with the experimental data. Besides, molecular electrostatic potential (MEP) distribution and non-linear optical properties of the title compound were investigated by theoretical calculations at the B3LYP/6-31 1++G(d,p) level. (C) 2011 Elsevier B.V. All rights reserved.Öğe Synthesis, spectroscopic, and thermal properties of some azomethine complexes of Cu(II), Ni(II), and Pt(II)(Springer, 2012) Turkyilmaz, Murat; Onder, Alper; Baran, YakupFour polydentate azomehines and their mono- and binuclear Pt(II), Cu(II), and Ni(II) complexes were synthesized and characterized. The resulting complexes were characterized by FTIR, magnetic measurements, elemental analysis, conductivity measurements, and thermal analysis. Electronic spectra and magnetic susceptibility measurements sustain the proposed distorted square-planar structures for the copper complexes. The electronic spectra display the characteristic pattern of square-planar stereochemistry for the other complexes. The thermal analyses have evidenced the thermal intervals of stability and also the thermodynamic effects that accompany them. Azomethine complexes have a similar thermal behavior for the selected metal ions. The decomposition processes as water elimination, chloride anion removal as well as degradation of the organic ligands were observed.Öğe Synthesis, spectroscopic, magnetic and thermal properties of copper(II), nickel(II) and iron(II) complexes with some tetradentate ligands: Solvatochromism of iron(II)-L2(Elsevier Science Sa, 2012) Onder, Alper; Turkyilmaz, Murat; Baran, YakupThe tetradentate azomethines were prepared by condensation of 2-piperazin-1-ylethanamine, (3-morpholin-4-ylpropyl)amine with 3-methylthophene-2-carbaldehyde, salicylaldehyde and 1H-imidazole-5-carbaldehyde. The ligands were characterized based on mass, H-1 and C-13 NMR, FTIR, and elemental analyses. New complexes of ligands with copper(II), iron(II) and nickel(II) were synthesized. Metal complexes are reported and characterized by magnetic, conductivity measurements, FTIR, elemental and thermal analyses (TG-DTA). Spectral analyses show that all the ligands behave as neutral tetradentate ligands and bind to the metal via azomethine N, piperazine N, salicylaldehyde O, morpholine O, imidazole N and thiophene S. Results of magnetic measurements and thermal studies show that the geometrical structures of the nickel(II) complexes are square planar while copper(II) and iron(II) are octahedral. The thermal behaviors of these complexes show that the hydrated complexes lose the hydration water molecule in the first step, followed immediately by decomposition of the anion and ligand molecules in subsequent steps. The solvatochromic behavior of the iron(II)-(L)2 complex was investigated using the electronic spectra of 1 x 10 (3) M in four different solvents. The solvatochromism was explained in terms of MLCT transition and solvent characteristics such as polarity, nature and acceptor-donor properties. (C) 2012 Elsevier B.V. All rights reserved.Öğe Synthetic, structural, spectroscopic, and stopped-flow kinetic investigation of imine production(Sage Publications Ltd, 2011) Baran, Yakup; Ozay, Hava; Esener, HasanSynthetic and formation kinetics studies have been made of imine production from the reaction of 3-methyl-2-thiophenecarboxyaldehyde with 3-(1H-imidazol-1-yl) propan-1-amine (L-1), 1-(3-aminopropyl) pyrolidin-2-one (L-2), 2-piperazin-1-ylethanamine (L-3) and 2-hydrazinopyridine (L-4). Kinetics were determined by rapid reaction techniques using absorbance changes at multi wavelengths in methanol. Activation enthalpies for imine formation in methanol vary from 101 to 121 kJ mol(-1) and entropies of activation (DS not equal) vary from -98 to -188 J K-1 mol(-1). All of these observations are indicative of an S(N)2 mechanism. Activation parameters of the reactions were calculated under second-order reaction conditions. The analysis of kinetic data in solutions was performed with the SPECFIT/32 software package which provides useful information on the binding characteristics of functional groups and mechanism of the reactions. The crystal structure of 3-methylthiophene-2-carbaldehyde pyridine-2-ylhydrazone is described.
