Creat membership Creat membership
Sign in

Forgot password?

  • Forgot password?
    Sign Up
  • Confirm
    Sign In
home > search

Now showing items 1 - 10 of 10

  • Synthesis, crystal structure and biological activity of the nickel(II) complex of 2,6-diacetylpyridinedihydrazone

    Azaz, A. Dilek   Celen, Selma   Namli, Hilmi   Turhan, Onur   Kurtaran, Raif   Kazak, Canan   Arslan, N. Burcu  

    A complex of Ni(II) with 2,6-diacetylpyridinedihydrazone (L) towards nickel(II) has been prepared and characterized by means of elemental analyses, IR, electronic spectra and single crystal X-ray analyses. [NiL(2)](NO(3)) was crystallized in the tetragonal space group P-4 21 c. The complex exhibits the expected coordination sphere with six nitrogen atoms coordinated to the central Ni(II) with a deformation from pseudo-octahedral geometry. Antimicrobial activities of the ligand and its complex were investigated.
    Download Collect
  • Electrokinetic and adsorption properties of sepiolite modified by 3-aminopropyltriethoxysilane

    Demirbas, Oezkan   Alkan, Mahir   Dogan, Mehmet   Turhan, Yasemin   Namli, Hilmi   Turan, Pinar  

    Surface modification of clay minerals has become increasingly important for improving the practical applications of clays such as fillers and adsorbents. An investigation was carried out on the surface modification of sepiolite with aminopropylsilyl groups in 3-aminopropyltriethoxysilane (3-APT). The zeta potential of the modified sepiolite suspensions was measured as a function of initial electrolyte concentration and equilibrium pH using a Zeta Meter 3.0 for modified sepiolite. The utility of the 3-APT-modified sepiolite was investigated as an adsorbent for removal of various heavy metal ions such as Fe, Mn, Co, Zn, Cu, Cd and Ni from aqueous solutions. The effects of various factors on the adsorption, such as pH, ionic strength and temperature of the solution were studied. The results showed that the amount adsorbed increases with solution pH in the pH range of 1.5 and 7.0; indicated that the modified sepiolite adsorbed Fe and Mn ions more than other metal ions such as Co, Zn, Cu, Cd and Ni. It was found that the temperature had an important effect on metal ion adsorption by the modified sepiolite. The adsorption isotherm has been determined and data have been analyzed according to the Langmuir and Freundlich models. (C) 2007 Elsevier B.V. All rights reserved.
    Download Collect
  • An FT-IR and DFT based new approach for the detection of tautomer proportions in solution

    Karabulut, Sedat   Namli, Hilmi  

    Tautomer proportions of acetylacetone (acac) in six different solvents are investigated with a new method by means of experimental absorptions (A) and theoretical absorption coefficients (e). The specific absorption bands (key bands) for keto and enol tautomers were obtained from recorded FT-IR spectra in related solution at room temperature. The molar absorption coefficients for key bands of both keto and enol tautomers were calculated, which is impossible to obtain with experimental methods for individual isomers in equilibrium. The Lambert-Beer equation is used to detect tautomer proportions. The obtained results are in consistence with literature. The most stable enol tautomer is found to be (86%) in CCI4 and the keto tautomer is found to be most stable in DMSO (48%). (C) 2012 Elsevier B.V. All rights reserved.
    Download Collect
  • In situ IR monitoring of complexation reaction between 2,6-bis(3,5-dimethylpyrazoyl)pyridine and some metal ions

    Turhan, Onur   Kurtaran, Raif   Namli, Hilmi  

    In situ complexation reactions between 2,6-bis(3,5-dimethylpyrazoyl)pyridine (bdmpp) and some transition metals (Cu(2+), Co(2+) and Ni(2+)) were studied with a new method in liquid cell using FT-IR. In this method, the spectrum of the solution of ligand was defined as a background, and then the changes in the FT-IR spectra by the addition of the metal salts were investigated. This method allows one to obtain the spectra of the ligand-metal complex before yielding the solid-state product. Complexation ratios (M/L) of these metals with bdmpp were found 1/1, 1/2 and 1/2, for Cu, Co and Ni, respectively. Studying with Mg(2+) and Ca(2+) ions showed that there were no interaction between bdmpp and these metal ions in methanol. (C) 2011 Elsevier B.V. All rights reserved.
    Download Collect
  • Detection of relative dimer and rotamer concentrations of diacetamide in different solvents by FT-IR spectroscopy and DFT calculations

    Karabulut, Sedat   Namli, Hilmi   Mella, Massimo  

    The relative rotamer, dimer and tautomer concentrations of diacetamide have been studied by means of infrared spectroscopy, with the recorded spectra being analyzed employing results from density functional theory calculations. It is observed that the cis-trans monomeric form of diacetamide (1) is found to be the most stable isomer in all studied solvents, with trans-trans diacetamide (2) being found to be 20% of total diacetamide in methanol. While the dimer form of diacetamide (3) is present only in carbon-tetrachloride (about 34% of the total), its tautomeric forms (4, 5) are not favorable in any of the studied solvents. (C) 2011 Elsevier B.V. All rights reserved.
    Download Collect
  • Simultaneous observation of reagent consumption and product formation with the kinetics of benzaldehyde and aniline reaction in FTIR liquid cell

    Namli, Hilmi   Turhan, Onur  

    Monitoring of a reaction in FrIR liquid cell has complex spectral futures due to the presence of solvent, unreacted reagents; acid catalysis and other additives. The current work was performed to study the kinetics of the reaction between benzaldehyde and aniline by simultaneous time dependent observation in FTIR liquid cell. Since the FTIR liquid cell used in this work was a closed system, background defining method allowed us to observe the changes in the concentration of each component in the liquid cell at different side of absorbance or transmittance axes. The changes in concentration arising from the reaction provide both the spectra and amount of the product and reagent, independently without having to isolate them from the reaction mixture. Therefore, it would be possible to follow the amount of decreases in concentration of the reagent and conversely, increases in concentration of the product. Consequently, using this method the reaction of benzaldehyde and aniline was found to go to equilibrium in chloroform. (c) 2006 Elsevier B.V. All rights reserved.
    Download Collect
  • Synthesis, characterization, crystal structure and thermal analysis of a copper(II) mononuclear compound with 2,6-bis(3,5-dimethyl-N-pyrazolyl) pyridine (bdmpp) and selenocyanate as ligands

    Kurtaran, Raif   Namli, Hilmi   Kazak, Canan   Turhan, Onur   Atakol, Orhan  

    A single crystal of the copper(II) compound, [Cu(bdmpp)(SeCN)(2)], 2, was obtained and its crystal structure was determined by X-ray diffraction methods. The complex was characterized by elemental, thermal and FTIR analysis. The FTIR analysis of the complex clearly shows the SeCN peaks at 2096 and 2061 cm(-1) which did not exist in the free organic ligand ( bdmpp). X-ray analysis showed that 2 crystallized in the monoclinic space group P2(1)/c. Cu(II) has a distorted trigonal bipyramidal coordination involving three N atoms from the ligand and two N atoms from the selenocyanate group.
    Download Collect
  • Characterization,adsorption,and electrokinetic properties of modified sepiolite

    Beyli, Pinar Turan   Dogan, Mehmet   Alkan, Mahir   Turkyilmaz, Aydin   Turhan, Yasemin   Demirbas, Ozkan   Namli, Hilmi  

    The metal ion adsorption and electrokinetic properties of sepiolite modified by 3-(trimetoxysilyl)propyl metaacrylate was studied. The characterization of modified sepiolite was made by Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning electron micrograph (SEM), and differential thermal analysis/thermogravimetry (DTA/TG). The adsorption behavior of Fe(III), Mn(II), Co(II), Zn(II), Cu(II), and Cd(II) metal ions on modified sepiolite from aqueous solutions was investigated as a function of equilibrium pH, temperature, and ionic strength. The adsorption experiments were carried out using a batch method. The initial and final concentrations of heavy metals were determined by means of atomic absorption spectrophotometry. The zeta potential of the modified sepiolite suspensions was measured as a function of metal ion concentration and equilibrium pH using a Zeta Meter 3.0. The results showed that the amount of adsorbed metal ions increased with solution pH, and that the modified sepiolite adsorbed Cu(II) and Mn(II) ions more than other metal ions. It was found that the temperature had an important effect on metal ion adsorption and that the adsorption process was endothermic in nature. Equilibrium isotherms for the adsorption of metal ions were measured experimentally. Results were analyzed by the Freundlich and Langmuir equations and determined the characteristic parameters for each adsorption isotherm. The isotherm data were reasonably well correlated by Langmuir isotherm. Maximum monolayer adsorption capacity of modified sepiolite for Cu(II), Mn(II), Zn(II), Fe(III), Co(II), and Cd(II) metal ions was calculated from 12.3x10(-5), 11.7x10(-5), 9.0x10(-5), 8.2x10(-5), 5.7x10(-5), and 1.8x10(-5)molL(-1), respectively. The affinity order of adsorption was Cu(II)>Mn(II)>Zn(II)-Fe(III)>Co(II)>Cd(II). The results indicate that modified sepiolite is good adsorbent for the removal of metal ions from aqueous solutions.
    Download Collect
  • Synthesis, characterization, crystal structure and biological activity of a novel heterotetranuclear complex: [NiLPb(SCN)2(DMF)(H2O)]2, bis-{[mu-N,N'-bis(salicylidene)-1,3-propanediaminato-aqua-nickel(II)](thiocyanato)(mu-thiocyanato)(mu-N,N'-dimethylformamide)lead(II)}.

    Kurtaran, Raif   Yildirim, Leyla Tatar   Azaz, Ayse Dilek   Namli, Hilmi   Atakol, Orhan  

    The mononuclear nickel complex NiL (LH2 = N,N'-bis(salicylidene)-1,3-diaminopropane) can be transformed into the tetranuclear complex [NiL(H2O)Pb(SCN)2(DMF)]2 in the aid of SCN-, DMF (dimethylformamide) and Pb(II) ions. The complex was characterized by elemental analysis and FTIR investigation. The crystal structure reveals it is a nonlinear Ni(II)-Pb(II)-Pb(II)i-Ni(II)i (i: 1-x, 1-y, 1-z) heterotetranuclear complex and crystallizes in the triclinic space group P1. The Ni(II) and Pb(II) ions have a distorted octahedral coordination geometry. There are three kinds of mu-bridge in the molecule between the metal ions. Each pair of Ni and Pb ions in the asymmetric unit is equatorially linked by two phenolic oxygen bridging atoms of N,N'-bis(salicylidene)-1,3-propanediaminato (salpd(2-), C17H16N2O2(2-)) ligand. The dinuclear centres from tetranuclear clusters Ni-Pb(i) and Ni(i)-Pb pairs are bridged by two mu-1,3-SCN groups. Pb(II) and Pb(II)i ions are also bridged by the oxygen atoms of DMF molecules. The tetranuclear units are hydrogen bonded by two O-H...N intermolecular interactions along the c-axis. The complex was screened for antibacterial and antifungal activities by the disc diffusion and microtiter plate techniques using DMF as solvent. The minimum inhibitory concentration values were calculated. It has been found that antimicrobial activities of the complexes are higher than the free ligand.
    Download Collect
  • Functionalized sepiolite for heavy metal ions adsorption

    Dogan, Mehmet   Turhan, Yasemin   Alkan, Mahir   Namli, Hilmi   Turan, Pinar   Demirbas, Oezkan  

    Surface modification of clays has become increasingly important due to the practical applications of clays such as fillers and adsorbents. The surface modification of sepiolite with [3-(2-aminoethylamino)propyl]trimethoxysilane has been employed. The modified sepiolite surface was investigated by FTIR, XRD and DTA/TG analysis. It was found that the chemical bonding takes place between the hydroxyl groups and/or oxygen atoms within the structure of sepiolite and methoxy groups of [3-(2-aminoethylamino)propyl]trimethoxysilane. The changes on electrokinetic properties of modified sepiolite particles were studied by measuring the zeta potential of particle as a function of metal concentration and equilibrium pH of solution. It was found that the zeta potential of the clay particles was always negative independent of the metal concentration in solution. This study also provides some evidence for the adsorption of metal ions on modified sepiolite. The adsorption of metal ions onto modified sepiolite has varied with the type of metal cations. The available basic nitrogen centers covalently bonded to the sepiolite skeleton were studied for Co(II), Cu(II), Mn(II), Zn(II), Fe(III) and Cd(II) adsorption from aqueous solutions. It was found that the amount of metal ion adsorbed onto modified sepiolite increases with increase in solution equilibrium pH and temperature, whereas it generally decreases with the ionic strength. The experimental data were correlated reasonably well by the Langmuir adsorption isotherm and the isotherm parameters (q(m) and K) were calculated. The ability to adsorb the cations gave a capacity order of Zn(II) > Cu(II) similar to Co(II) > Fe(III) > Mn(II) > Cd(II) with affinities of 2.167x 10(-4), 1.870x10(-4), 1.865x10(-4), 1.193x10(4), 0.979x 10(-4) and 0.445x 10(-4) mol g(-1), respectively.
    Download Collect


If you have any feedback, Please follow the official account to submit feedback.

Turn on your phone and scan

Submit Feedback