5 results
Search Results
Now showing 1 - 5 of 5
Article Citation - WoS: 36Citation - Scopus: 42Synthesis, Spectroscopy and Electrochemical Behaviors of Nickel(ii) Complexes With Tetradentate Shiff Bases Derived From 3,5-bu2t<(Pergamon-elsevier Science Ltd, 2005) Kasumov, VT; Özalp-Yaman, S; Tas, ENickel(II) complexes of a series of N,N'-polymethylenebis(3,5-Bu'(2)-salicylaidimine) ligands containing 2,4-di-Bu'(2)-phenol arms, NiLx, were synthesized and their spectroscopic and redox properties were examined. The UV-vis, H-1 NMR spectroscopic and magnetic results indicate that complexes NiL1-NiL4 unlike NiL5 and NiL6 have a square-planar structure in the solid state and in solution. Cyclic voltammograms of NiLx (x= 1-4) complexes displayed two-step oxidation processes. The first oxidation peak potentials of all Ni(II) complexes corresponds to the reversible one-electron oxidation process of the metal center, yielding Ni(III) species. The second oxidation peak of the complexes was assigned as the ligand based oxidation generating a coordinated phenoxyl radical species. (c) 2005 Elsevier B.V. All rights reserved.Article Citation - WoS: 14Citation - Scopus: 19Electrochemistry of nickel(II) complexes with N,N'-bis(3,5-di-tert-butylsalicylidene)polymethylenediamines(Pergamon-elsevier Science Ltd, 2005) Özalp-Yaman, S; Kasumov, VT; Önal, AMThe electrochemical oxidation of several N,N'-polymethylenebis(3,5-di-tert- butylsalicylaldiminato)nickel(II) complexes, Ni(L-x), has been studied by cyclic voltammetry and in situ UV-Vis spectroscopy in DMF Cyclic voltammograms of Ni(L-x) (x = 1-4) complexes displayed two-step oxidation processes under nitrogen gas atmosphere. The first oxidation peak potentials of all the Ni(II) complexes corresponds to the reversible one-electron oxidation process of the metal center, yielding Ni(III) species. EPR spectrum of the electrolysis solution was recorded after one electron transfer at liquid nitrogen temperature also confirms the formation of [Ni-III (L-3)](+) species (g(x) > g(y) > g(z)) with a (2)A(1)(d(z)(2))(1) ground state. Upon addition of pyridine to one electron oxidised solutions a new penta coordinated species, [Ni-III(L-3)Py](+) (g(perpendicular to) > g(parallel to), a(parallel to)(N-14) = 8 G), was produced. The second oxidation peak of the complexes was assigned as the ligand based oxidation, generating a coordinated phenoxy radical species. (c) 2005 Elsevier Ltd. All rights reserved.Article Citation - WoS: 13Electrochemical and Quantum Chemical Studies on Mitomycin and Adriamycin(Elsevier, 2003) Özalp-Yaman, S; Önal, AM; Türker, LIn-situ spectroelectrochemical redox behaviour of two prominent chemotherapeutic agents, mitomycin and adriamycin were studied at constant potential. AM 1 (UHF) type quantum chemical calculations on the neutral as well as radical anion and cation forms of mitomycin and adriamycin were performed. (C) 2003 Elsevier Science B.V. All rights reserved.Article Citation - WoS: 4Citation - Scopus: 7Simultaneous Novel Synthesis of Conducting and Non-Conducting Halogenated Polymers by Electroinitiation of (2,4,6-Trichloro or 2,6-Dichlorophenolato)ni(ii) Complexes(Elsevier Sci Ltd, 2005) Özalp-Yaman, S; Özalp Yaman, Şeniz; Bastürkmen, M; Kisakürek, D; Özalp Yaman, Şeniz; Chemical Engineering; Chemical EngineeringNiL2(Ph)(2)(.)xH(2)O [L=3,5-dimethylpyrazole or N-methyl imidazole; Ph=DCP or TCP; x=0, 1 or 3] complexes were synthesised and characterised by analytical and spectroscopic methods using elemental analysis and FTIR. The electrochemical behavior of the complexes was studied by cyclic voltammetry in tetrabutylammoniumtetrafluoroborate-N,N-dimethylformamide electrolyte-sol vent couple. Cyclic voltammogram of the complexes displayed two-step oxidation processes under the nitrogen gas atmosphere. The polymerization of the complexes was accomplished in the same solvent-electrolyte couple by the constant potential electrolysis of NiL2(Ph)(2)(.)xH(2)O, synthesizing the poly(di- or monochlorophenylene oxide)s via free radical mechanism. The simultaneous polymerization of non-conducting polymer and conducting polymer (the conductivity of 0.7 S cm(-2)) were achieved by electroinitiated polymerization of Ni(DMPz)(2)(TCP)(2). The structural analysis of the polymers were performed using FTIR, H-1 NMR and C-13 NMR spectroscopic techniques and DSC for the thermal analysis. The kinetics of the polymerization was followed by in situ UV-vis spectrophotometer during the electrolysis. The low temperature ESR spectrum of the electrolysis solution also confirmed the formation of phenol radical (g=2.0028). One electron oxidation process of NiL2(DCP)(2)(.)xH(2)O produces a new Ni(II) complex, Ni(L-L)(DCP)(2)(S) by the rapid decomposition of (NiL2)-L-III(DCP)(2) into a ligand radical producing a singlet with the g value of 2.0015. Second electron oxidation process generates oligemers, which could not be isolated from the electrolyte solution. (c) 2005 Elsevier Ltd. All rights reserved.Article Citation - WoS: 14Citation - Scopus: 12Synthesis, Characterization, Redox Behavior and Hydrogenation Catalytic Activity of Bis(n-aryl-3, 5-but< Complexes(Pergamon-elsevier Science Ltd, 2005) Kasumov, VT; Tas, E; Köksal, F; Özalp-Yaman, SThe synthesis, spectroscopic (H-1 NMR, IR, UV-Vis), electron-transfer properties and catalytic reactivity of new palladium(II) complexes, with N-aryl-3,5-Bu-2(t)-salicylaldimines prepared from 3,5-Bu-2(t)-salicylaldehyde and o-,p-substituted anilines (X-C6H4NH2, X = H. F. Cl, Br, CH3, OCH3, t-Bu, 5,6-benzo) are reported. Cyclic voltammetry studies of the complexes exhibit an irreversible anodic peak that corresponds to the phenoxide/phenoxyl oxidation. The chemical oxidation of the complexes with (NH4)(2)Ce(NO3)(6) in CHCl3, besides relatively stable Pd-II-phenoxyl radical complexes (g = 2.0083-2.0114), also generate nitroxide radicals exhibiting strongly anisotropic spectra (g(parallel to) = 2.0061, g(perpendicular to) = 2.0072, A(parallel to) = 37.5, A(perpendicular to) = 5.38 G) typical for immobilized nitroxide radicals. It has been found that the introduction of t-Bu groups on the salicylic ring increases catalytic activity of towards hydrogenation of nitrobenzene in DMF at room temperature. (C) 2004 Elsevier Ltd. All rights reserved.
