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Öğe Synthesis, characterization and electro-spectroelectrochemical studies of four macrocyclic Schiff-base Co(II) complexes having N2O2 set of donor atoms(Springer, 2009) Yilmaz, Ismail; Ilhan, Salih; Temel, Hamdi; Kilic, AhmetFour macrocyclic Schiff-base cobalt complexes, [CoL1][NO3](2) center dot A 3H(2)O, [CoL2][NO3](2) center dot A 4H(2)O, [CoL3][NO3](2) center dot A 4H(2)O and [CoL4][NO3](2) center dot A 2H(2)O, were synthesized by reaction of salicylaldehyde derivatives with 1,4-bis(3-aminopropoxy)butane or (+/-)-trans-1,2-diaminocyclohexane and Co(NO3)(2) center dot A 6H(2)O by template effect in methanol. The metals to ligand ratio of the complexes were found to be 1:1. The Co(II) complexes are proposed to be tetrahedral geometry. The macrocyclic Co(II) complexes are 1:2 electrolytes as shown by their molar conductivities (I >(M)) in DMF (dimethyl formamide) at 10(-3) M. The structure of Co(II) complexes is proposed from elemental analysis, Ft-IR, UV-visible spectra, magnetic susceptibility, molar conductivity measurements and mass spectra. Electrochemical and thin-layer spectroelectrochemical studies of the complexes were comparatively studied in the same experimental conditions. The electrochemical results revealed that all complexes displayed irreversible one reduction processes and their cathodic peak potential values (E (pc)) were observed in around of -1.14 to 0.95 V. It was also seen that [CoL1][NO3](2) center dot A 3H(2)O and [CoL2][NO3](2) center dot A 4H(2)O exhibited one cathodic wave without corresponding anodic wave but, [CoL3][NO3](2) center dot A 4H(2)O and [CoL4][NO3](2) center dot A 2H(2)O showed one cathodic wave with corresponding anodic wave, probably due to the presence of different ligand nature even if the complexes have the same N2O2 donor set. In view of spectroelectrochemical studies [CoL3][NO3](2) center dot A 4H(2)O showed distinctive spectral changes in which the intensity of the band (lambda A = at 316 nm, assigned to n -> pi* transitions) decreased and a new broad band in a low intensity about 391 nm appeared as a result of the reduction process based on the cobalt center in the complex.Öğe Synthesis, Spectral Characterization and Electrochemical Investigations of Mononuclear Cu (II), Ni (II) and Co (II) Metal Complexes Containing Different New vic-dioxime Groups(Taylor & Francis Inc, 2009) Tas, Esref; Kara, Hatice; Durgun, Mustafa; Kilic, Ahmet; Yilmaz, IsmailThree new vic-dioxime: N-(2-methyl-2-butylamine)-anti-p-tolylglyoxime (L1H2), N-(4-amino-2,2,6,6-tetramethylpiperidine)-anti-p-tolylglyoxime (L2H2) and N,N'-(4-amino-2,2,6,6-tetramethylpiperidine)-anti-glyoxime (L3H2) were prepared by the reaction of anti-p-tolylchloroglyoxime and anti-dichloroglyoxime with 2-methyl-2-butylamine and 4-amino-2,2,6,6-tetramethylpiperidine in absolute THF at -15 degrees C. Mononuclear metal complexes with a metal-ligand ratio of 1:2 were prepared using Cu(II), Ni(II) and Co(II) salts. FT-IR spectra show that the ligands act in a tetradentate manner and coordinates N4 donor groups of ligands to Cu(II), Ni(II) and Co(II) ions. The Cu(II) complexes of these ligands are proposed to be square-planar; the Ni(II) and Co(II) complexes are proposed to be octahedral with two water molecules as axial ligands. The ligands and their metal complexes were characterized by elemental analyses, Ft-IR, UV-Vis, 1H and 13C-NMR spectra, magnetic susceptibility measurements and cyclic voltammetry. The electrochemical behavior of the Ni(II), Co(II) and Cu(II) complexes was investigated by cyclic voltammetry in DMSO as well.Öğe The orthopalladation dinuclear [Pd(L1)(?-OAc)]2, [Pd(L2)(?-OAc)]2 and mononuclear [Pd(L3)2] complexes with [N, C, O] or [N, O] containing ligands: Synthesis, spectral characterization, electrochemistry and catalytic properties(Elsevier Science Sa, 2010) Kilic, Ahmet; Kilinc, Dilek; Tas, Esref; Yilmaz, Ismail; Durgun, Mustafa; Ozdemir, Ismail; Yasar, SedatTreatment of the salicylaldimine ligands (L1H, L2H, L3H, L4H and L5H) with palladium(II) acetate in absolute ethanol gave the orthopalladation dinuclear [Pd(L-1)(mu-OAc)](2), [Pd(L-2)(mu-OAc)](2) and mononuclear [Pd(L-3)(2)] with the tetradentate ligands [N, C, O] or [N, O] moiety. The ligands L1H and L2H are coordinated through the imine nitrogen and aromatic ortho carbon atoms, whereas the ligand L3H coordinated through the imine nitrogen and phenolic oxygens atoms. The Pd(II) complexes have a square-planar structure and were found to be effective catalysts for the hydrogenation of both nitrobenzene and cyclohexene. These metal complexes were also tested as catalysts in Suzuki-Miyaura coupling of aryl bromide in the presence of K2CO3. The catalytic studies showed that the introduction of different groups on the salicyl ring of the molecules effected the catalytic activity towards hydrogenation of nitrobenzene and cyclohexene in DMF at 25 and 45 degrees C. The Pd(II) complexes easily prepared from cheap materials could be used as versatile and efficient catalysts for different C-C coupling reactions (Suzuki-Miyaura reactions). The structure of ligands and their complexes was characterized by UV-Vis, FT-IR, H-1 and C-13 NMR, elemental analysis, molar conductivity, as well as by electrochemical techniques. (C) 2009 Elsevier B.V. All rights reserved.