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    Conversion of CO2 into cyclic carbonates in the presence of metal complexes as catalysts
    (Science Reviews 2000 Ltd, 2010) Kilic, Ahmet; Durgun, Mustafa; Ulusoy, Mahmut; Tas, Esref
    The sterically hindered salicylaldimine ligands N,N'-(1,5-diaminonaphthalene)-3,5-bu(2)(t)-salicylaldimine (L-1), N,N'-(2,7-diaminofluaren)-3,5-bu(2)(t)-salicylaldimine (L-2) and N,N'-(1,8-diaminonaphthaline)-3,5-bu(2)(t)-salicylaldimine (L-3) have been synthesised by the condensation of 1,5-diaminonaphthalene, 2,7-diaminofluarene, and 1,8-diaminonaphthaline with 3,5-di-tert-butylsalicylaldehyde, respectively. Dinuclear M(II) complexes of L-1 and L-2 and mononuclear M(II) complexes of L-3 have been prepared using Cu(II), Ni(II), Co(II), and Mn(II) salts and characterised. The synthesised sterically-hindered, salen-type complexes were tested as catalysts for the formation of cyclic carbonates from CO2 and liquid epoxides (propylene oxide, epichlorohydrine, 1,2-epoxybutane and styrene oxide), which served as both reactant and solvent. Ligand structure and the type of metal centre have a marked influence on the catalytic activity. Mn(II) complexes showed the highest catalytic activity.
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    Syntesis, Crystallographic Structure and Semiempirical Studies of a Novel Complexes of Uranyl(VII).
    (Int Union Crystallography, 2009) Tek, Ahmed Arif; Celik, Omer; Ulusoy, Mahmut; Iskeleli, Nazan Ocak; Eroglu, Erol; Tas, Esref
    [Abstract Not Available]
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    Synthesis of new boron complexes: application to transfer hydrogenation of acetophenone derivatives
    (Wiley-Blackwell, 2011) Kilic, Ahmet; Kayan, Cezmi; Aydemir, Murat; Durap, Feyyaz; Durgun, Mustaf; Baysal, Akin; Tas, Esref
    Two new boron complexes were synthesized from N-[3-(methylmercapto)aniline]-3,5-di-tert-butylsalicylaldimine (LH) with boron reagent BPh3 or BF3 center dot Et2O. These boron complexes are stable and easily soluble in protic solvents such as ethanol (C2H5OH) but hardly soluble in nonprotic solvents such as chloroform (CHCl3), dichloromethane (CH2Cl2) and tetrahydrofuran (THF). All new boron complexes have been fully characterized by both analytical and spectroscopic methods. The catalytic activities of complexes [LBPh2], 2, and [LBF2], 3, in the transfer hydrogenation of acetophenone derivatives were tested. Stable boron complexes were found to be efficient catalysts in the transfer hydrogenation of aromatic ketones in good conversions up to 99% in the presence of iso-PrOH/KOH. Copyright (C) 2011 John Wiley & Sons, Ltd.
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    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, Ismail
    Three 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.
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    Synthesis, spectroscopic, thermal analysis and in vitro cytotoxicity, anticholinesterase and antioxidant activities of new Co(II), Ni(II), Cu(II), Zn (II), and Ru(III) complexes of pyrazolone-based Schiff base ligand
    (Elsevier, 2023) Cakmak, Resit; Ay, Burak; Cinar, Ercan; Basaran, Eyup; Akkoc, Senem; Boga, Mehmet; Tas, Esref
    Metal-based drugs have gained significant importance in medicine in recent years. In this research, a series of new Co(II), Ni (II), Cu (II), Zn(II), and Ru(III) complexes of a Schiff base ligand, (1,5-dimethyl-4-((1-(3-nitrophenyl)ethylidene) amino)-2-phenyl-1,2-dihydro-3H-pyrazol-3-one), were prepared for the first time in excellent yields, and characterized by elemental analysis, FT-IR, 1H NMR, 13C NMR, ICP-OES, and thermal analysis. The in vitro antiproliferative, anticholinesterase, and antioxidant properties of complexes 1-5 were evaluated. The cytotoxic effects of complexes 1-5 on the viability of colon cancer (DLD-1), breast cancer (MDA-MB-231), and healthy lung (Wl-38) cell lines were investigated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method in vitro. The anticancer activities of the ligand and its metal complexes were lower than those of the reference drug, cisplatin. In anticholinesterase activity studies, complex 4 (88.46 +/- 0.45% inhibition) in butyrylcholinesterase (BChE) assay showed a higher inhibitory effect than the standard compound galanthamine with 78.14 +/- 0.55% inhibition. In antioxidant assays, some complexes showed higher antioxidant activities than standard antioxidant butylated hydroxytoluene (BHT). Among the prepared complexes, complex (4) (IC50=5.91 +/- 0.17 mu M) in ABTS assay showed the highest antioxidant activity compared to BHT (IC50=16.19 +/- 0.17 mu M). Also, this complex (IC50=10.17 +/- 0.36 mu M) showed the best antioxidant activity in CUPRAC assay compared to BHT (IC50=39.37 +/- 0.12 mu M).
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    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, Sedat
    Treatment 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.