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Öğe Determination of Thermodynamic Parameters of Some Complexes of 9-Ethyl-3-Carbazolecarboxaldehyde 4-Phenyl-3-Thiosemicarbazone (Eccapt)(2000) Akgemci, Emine Güler; Atalay, TevfikThe complexes of Cu(II), Co(II), Zn(II), and Cd(II) with 9-ethyl-3-carbazolecarboxaldehyde 4-phenyl- 3-thiosemicarbazone were synthesized and their stability constants were determined using a spectropho- tometric method at different temperatures (25, 30, 35 and 40±0.1 °C) and ionic strengths (0.05, 0.01 and 0.20 M KNO3) in 50% (v/v) aqueous DMF. From these constants, the thermodynamic stability constants and thermodynamic parameters (AG, AH and AS°) were calculated.Öğe Electrochemical investigation of heavy metal ion transfer across the water/1,2-dichloroethane interface assisted by 9-ethyl-3-carbazolecarboxaldehyde-thiosemicarbazone(WILEY-V C H VERLAG GMBH, 2007) Bingöl, Haluk; Akgemci, Emine Güler; Ersöz, Mustafa; Atalay, TevfikThe transfer of heavy metal ions across the polarized water/1,2-dichloroethane (1,2-DCE) interface assisted by 9ethyl-3-carbazolecarboxaldehyde-thiosemicarbazone (ECCAT) in the 1,2-DCE phase has been studied by cyclic voltammetry. Voltammetric waves of Pb(II) and Cd(II) ions were reversible and quasi-reversible, respectively, whereas that of Hg(II) and Zn(II) ion were irreversible. The voltammogram of Cu(II) ion showed a two-step wave, however the nature of the transfer could not be satisfactorily evaluated by analyzing the cyclic voltammetric data. When Ni(II) and Co(II) was used no peak was visible under the experimental conditions used in this study. The dependence of the half-wave potentials of Pb(II) and Cd(II) ions on the ligand concentration reveals that their ion-transfer is assisted by the formation of 1:3 metal-ECCAT complex in 1,2-DCE. The over-all association constants of [Pb(ECCAT)(3)](2+) and [Cd(ECCAT)(3)](2+) complexes in DCE-phase have been determined to be log beta(3)(0)= 14.03 and log beta(0)(3) = 15.44, respectively.Öğe Evaluation of Thermodynamic Parameters and Stability-Constants of Cu(Ii), Ag(I) and Hg(Ii) Complexes of 2-Methylindole-3-Carboxaldehyde Thiosemicarbazone(ELSEVIER SCIENCE BV, 1994) Atalay, Tevfik; Özkan, ErdalThe stability of Cu(II), Ag(I) and Hg(II) complexes of 2-methylindole-3-carboxaldehyde thiosemicarbazone have been determined using a spectrophotometric method in 50% (v/v) aqueous ethanol at different ionic strengths (0.12, 0.22 and 0.4 M) and at different temperatures (25, 30, 35 and 40 +/- 0.1 degrees C). For each metal-ligand system at each temperature, the thermodynamic stability constant (In K-theta) was obtained graphically at zero ionic strength from plots of In K versus ionic strength. The thermodynamic parameters were evaluated from plots of In K-theta versus 1/T.Öğe Interfacial Transfer of Cd2+ Assisted by 4 '-Morpholino-Acetophenone-4-Phenyl-3-Thiosemicarbazone Across the Water/1,2-Dichloroethane Interface(Versita, 2010) Bingöl, Haluk; Atalay, TevfikThe assisted transfer of heavy metal ions by interfacial complexation with 4'-morpholinoacetophenone-4-phenyl-3-thiosemicarbazone (MAPPT) at the interface between two immiscible electrolyte solutions (ITIES) was studied by cyclic voltammetry. The voltammograms obtained across the water/1,2-dichloroethane interface using the MAPPT ligand in the organic phase shows that the assisted metal ion transfers have different nature for different ions. The quasi-reversible voltammetric peak of the Cd2+ ion was obtained and is discussed in detail. The dependence of the half-wave transfer potential on MAPPT concentration showed that the equilibrium is effectively displaced towards a 1:3 (metal:ligand) stoichiometry with an association constant of log beta(0) = 15.46 (+/- 0.11) for the Cd2+ ion, corresponding to the TIC/TID mechanism.Öğe Kinetic-spectrophotometric determination of cobalt with 2-methylindole-3- carboxaldehyde 4-phenyl-3-thiosemicarbazone(1995) Özkan, Erdal; Atalay, Tevfik[Abstract not Available]Öğe New copper(II) and nickel(II) complexes of 4-morpholinoaceto-phenone thiosemicarbazone: Structural, electrochemical and antimicrobial studies(WILEY-V C H VERLAG GMBH, 2007) Bingöl, Haluk; Coşkun, Ahmet; Akgemci, Emine Güler; Kaya, Baştürk; Atalay, Tevfik4-Morpholinoacetophenone thiosemicarbazone, MAPT, and its nickel(II) and copper(II) complexes have been prepared and characterized by elemental analysis, magnetic susceptibility, spectral methods (FT-IR, H-1 NMR) and cyclic voltammetry. Electrochemical behaviors of the complexes have been studied by cyclic voltammetry in DMF media showing metal centered reduction processes for both of them. The redox properties, nature of the electrode processes and the stability of the complexes were discussed. [Cu(MAPT)(2)]Cl-2 complex shows Cu(II)/Cu(I) couple and quasi-reversible wave associated with the Cu(III)/Cu(II) process. The reduction/oxidation potential values depend on the structures of complexes. Also, the antimicrobial activities of these complexes were determined against S. aureus, E. coli and B. subtilis.Öğe Some Thermodynamic Parameters of Co (II), Ni (II) and Cu (II) Complexes of Benzylaminophenylglyoxime(1996) Atalay, Tevfik; Alpaydın, Sabri[Abstract not Available]Öğe Synthesis of a Novel Thiadiazine Derivative and Electrochemical Properties for Pb2+ Transfer across Water/1,2-Dichloroethane Interface(PEKING UNIV PRESS, 2011) Baslak, Canan; Bingol, Haluk; Coskun, Ahmet; Atalay, TevfikThe transfer of Pb2+ facilitated by interfacial complexation with 5-(4-phenoxyphenyl)-6H-1,3,4-thiadiazin-2-amine (PPTA) at the polarized water/1,2-dicholoroethane (1,2-DCE) interface was investigated by cyclic voltammetry. We synthesized the thiadiazine derivative, PPTA, firstly. The transfer was performed at different metal concentrations and scan rates, and the obtained voltammetric transfer peaks toward Pb2+ ion over other divalent cations (Zn2+, Co2+, Ni2+, Cd2+, Hg2+, and Cu2+) were reversible. The dependence of the half-wave potentials of the Pb2+ ion on the concentration of PPTA in the organic phase indicates that the ion transfer is facilitated by the formation of 1:2 (metal: ligand) complex in the organic phase with the association constant (Ig beta(2)) of (17.1 +/- 0.2).Öğe Thermodynamic Studies of Some Complexes of 2-Benzoylpyridine 4-Phenyl 3-Thiosemicarbazone(SCIENTIFIC TECHNICAL RESEARCH COUNCIL TURKEY, 1998) Atalay, Tevfik; Akgemci, Emine GülerThe stability constants of the Co(II), Ni(II), Cu(II) and Zn(II) complexes with 2-benzoylpyridine 4-phenyl-3-thiosemicarbazone were determined using a spectrophotometric method at different temperatures (25, 30, 35 and 40 +/- 0.1 degrees C) and ionic strengths (0.05, 0.01 and 0.20 M KNO3) in 50 % (v/v) aqueous ethanol. Plots of thermodynamic stability constants at zero ionic strength (ln K degrees) versus T-1 gave linear curves and Delta H degrees and Delta S degrees were also calculated from these plots. Moreover, the changes in free energy for each metal-ligand system were calculated from the following equation. Delta G degrees = -RT ln K degrees.Öğe Voltammetric determination of facilitated ion transfer across the water/1,2-dichloroethane interface(PLEIADES PUBLISHING INC, 2014) Baslak, Canan; Atalay, TevfikThe facilitated transfer characteristics of Cd2+ ion by 4-morpholinoacetophenone-4-ethyl-3-thiosemicarbazone (MAPET) across water/1,2-dicholoroethane (1,2-DCE) interface and its electrochemical properties were investigated by voltammetric measurements. Cyclic voltammetry (CV) was employed to examine the transfer in the conditions of the ligand (organic phase) in excess and the obtained transfer peaks have reversible nature at different metal concentrations and scan rates. The dependence of the obtained half-wave transfer potential on MAPET concentration showed that the equilibrium is effectively displaced towards a 1: 3 (Cd2+: ligand) stoichiometry with an association constant of log beta (3) (0) = 12.96 +/- 0.09 for the Cd2+ ion, corresponding to the TIC/TID mechanism.
