Yazar "Çetinkaya, B" seçeneğine göre listele

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    1,1?,3,3?-tetraalkyl-2,2?-biperimidinylidenes
    (John Wiley & Sons Inc, 2003) Alici, B; Hökelek, T; Çetinkaya, E; Çetinkaya, B
    C-2 deprotonation of 1,3-dibutylperimidinium bromide (1a) with sodium hydride and a catalytic amount of potassium tert-butoxide in dry THF led to the formation of the exceptionally inert tetraaminoalkene 2a. In contrast, isostructural tetrakis(2-methoxyethyl)-tetraaminoalkene (2b) instantaneously reacted with O-2 to yield urea 3b, and silver nitrate was readily reduced with 2b to form a silver mirror. Compound 2a has been characterized by X-ray diffraction studies; the naphtho-pyrimidine skeleton imposes structural constraints and some rigidity to the C=C bonding. (C) 2003 Wiley Periodicals, Inc.
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    1,4,5,6-tetrahyropyrimidinium halides ligands for Suzuki-Miyaura cross-coupling of unactivated aryl chlorides
    (Pergamon-Elsevier Science Ltd, 2005) Alici, B; Özdemir, I; Gürbüz, N; Çetinkaya, E; Çetinkaya, B
    Four functionalized bis(1,4,5,6-tetrahyropyrimidinium) salts (2a-d) have been prepared and characterized by conventional spectroscopic methods and elemental analyses. A highly effective, easy to handle and environmentally benign process for palladium mediated Suzuki cross-coupling was developed. The in situ prepared three component system Pd(OAC)(2) / bis(1,4,5,6-tetrahyropyrimidinium) bromides (2a-d) and CS2CO3 catalyses quantitatively the Suzuki cross-coupling of deactivated aryl chloride.
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    2-imidazoline and 1,4,5,6-tetrahydropyrimidine-ruthenium(II) complexes and catalytic synthesis of furan
    (Elsevier Science Sa, 1999) Çetinkaya, B; Alici, B; Özdemir, I; Bruneau, C; Dixneuf, PH
    The complexes RuCl2(L-1)(arene) (3-4) (L1 = HC=NCH2CH2NR, R = Et, arene = p-MeC6H4CHMe2 or C6Me6) and RuCl2(L-2)(arene) (5-6) (L-2 = HC=NCH2CH2CH2NR, R = Me; Ph, CH2Ph, p-MeC6H4) have been synthesized by reaction of [RuCl2(arene)](2), with 1-alkyl-2-imidazoline (1) or 1-alkyl-1,4,5,6-tetrahydropyrimidine (2). In each of these complexes (3-6) the ligand is bound via the imine (N=C) nitrogen atom. The new complexes are capable of catalyzing the activation of (2)-3-methylpent-2-en-4-yn-1-ol into 2,3-dimethylfuran in very good yield, via intramolecular cyclization, and the 1,4,5,6-tetrahydropyrimidine complexes 5 and 6 appeared to be the best catalyst precursors. Cyclic voltammetry shows that the nature of the arene ligand, rather than that of the nitrogen containing ligand, controls the electron-richness of the complexes. (C) 1999 Elsevier Science Ss.A. All rights reserved.
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    ?6-mesityl,?1-imidazolinylidene-carbene-ruthenium(II) complexes
    (Wiley-V C H Verlag Gmbh, 2003) Çetinkaya, B; Demir, S; Özdemir, I; Toupet, L; Sémeril, D; Bruneau, C; Dixneuf, PH
    The reaction of electron-rich carbene-precursor olefins containing two imidazolinylidene moieties [(2,4,6-Me3C6H2CH2)NCH2CH2N(R)C=](2) (2a: R = CH2CH2OMe, 2b R = CH(2)Mes), bearing at least one 2,4,6-trimethylbenzyl (R = CH(2)Mes) group on the nitrogen atom, with [RuCl2(arene)](2) (arene = p-cymene, hexamethylbenzene) selectively leads to two types of complexes. The cleavage of the chloride bridges occurs first to yield the expected (carbene) (arene)ruthenium(H) complex 3. Then a further arene displacement reaction takes place to give the chelated eta(6)-mesityl,eta'-carbene-ruthenium complexes 4 and 5. An analogous eta(6)-arene-eta(1)-carbene complex with a benzimidazole frame 6 was isolated from an in situ reaction between [RuCl2(p-cymene)](2), the corresponding benzimidazolium salt and cesium carbonate. On heating, the RuCl2(imidazolinylidene) (p-cymene) complex 8, with p-methoxybenzyl pendent groups attached to the N atoms, leads to intramolecular p-cymene displacement and to the chelated eta(6)-arene,eta(1)-carbene complex 9. On reaction with AgOTf and the propargylic alcohol HC=CCPh20H, compounds 4-6 were transformed into the corresponding ruthenium allenylidene intermediates (4-->10, 5-->11, 6-->12). The in situ generated intermediates 10-12 were found to be active and selective catalysts for ring-closing metathesis (RCM) or cycloisomerisation reactions depending on the nature of the 1,6-dienes. Two complexes [RuCl2-{eta(1)-CN(CH2C6H2Me3-2,4,6)CH2CH2N- (CH2CH2OMe)}(C6Me6)] 3 with a monodentate carbene ligand and [RuCl2-{eta(1)-CN[CH2(eta(6)-C6H2Me3-2,4,6)]CH2CH2N-(CH2C6H2Me3-2,4,6)}] 5 with a chelating carbene-arene ligand were characterised by X-ray crystallography.
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    Access to 3-methyl-4-methylene-N-tosylpyrrolidine and 3,4-dimethyl-N-tosylpyrroline by ruthenium-catalyzed cascade cycloisomerization/isomerization reactions
    (Wiley-V C H Verlag Gmbh, 2004) Özdemir, I; Çetinkaya, E; Çetinkaya, B; Çicek, M; Sémeril, D; Bruneau, C; Dixneuf, PH
    New RuCl2(benzimidazole)(arene) complexes have been prepared. Upon reaction with 1,1-diphenylprop-2-ynol they generate catalyst precursors which perform the cycloisomerization of diallyltosylamide into 3-methyl-4-methylene-N-tosylpyrrolidine. The presence of N-(2,4,6-trimethyl-benzyl)benzimidazole as ligand leads to a subsequent isomerization and gives the 3,4-dimethyl-N-tosylpyrroline. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
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    Antibacterial and antifungal activities of complexes of ruthenium (II)
    (Georg Thieme Verlag Kg, 1999) Çetinkaya, B; Özdemir, I; Binbasioglu, B; Durmaz, R; Günal, S
    Twenty ruthenium (IT) complexes (1-5) were evaluated for their in vitro antibacterial and antifungal activity against Enterococcus faecalis (ATCC 29212), Staphylococcus aureus (ATCC 29213), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Candida albicans and Candida tropicalis. Compounds Id! le, Ih, ii and Ij showed more pronounced antimicrobial activity against Gram-positive bacteria and fungi as compared to the nitrogen donor ruthenium complexes; hydrophobic substituents were significantly mon effective. None of the compounds 1-5 exhibited antimicrobial activity against the Gram-negative strains Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 27853) with the concentrations ranging between 17.5 and 800 mu g/ml.
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    Benzimidazole, benzothiazole and benzoxazole ruthenium(II) complexes;: Catalytic synthesis of 2,3-dimethylfuran
    (Wiley-V C H Verlag Gmbh, 2000) Çetinkaya, B; Özdemir, I; Bruneau, C; Dixneuf, PH
    Fourteen ruthenium(II) complexes of the type [RuCl2(eta(6)-arene)L], (arene = 1,4-MeC6H4Pri or C6Me6; L = benzimidazole derivative in which the NH group is substituted by N-alkyl or isoelectronic O or S atoms) have been prepared by cleavage of [RuCl2(eta(6)-arene)](2) with the N-heterocycle L. Their spectroscopic and electrochemical properties are described. The effect of the nature of the benzazole (L) on the catalytic activity of these complexes for the intramolecular cyclization of (Z)-3-methylpent-2-en-4-yn-1-ol into 2,3-dimethylfuran has also been studied; the benzimidazole complexes were found to be the most active.
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    Benzimidazolin-2-ylidene-palladium-catalysed coupling reactions of aryl halides
    (Wiley, 2005) Gök, Y; Gürbüz, N; Özdemir, I; Çetinkaya, B; Çetinkaya, E
    The in situ prepared three-component system Pd(OAC)(2)-1,3-dialkylbenzimidazolium chlorides (2a-f) and CS2CO3 catalyses, quantitatively, the Suzuki cross-coupling of deactivated aryl chlorides and Heck coupling reactions of aryl bromide and iodide substrates. The 1,3-dialkylbenzimidazolium salts (2a-f) were characterized by conventional spectroscopic methods and elemental analysis. Copyright (c) 2005 John Wiley & Sons, Ltd.
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    Dichloro[3-(1-naphthylmethyl)-1-(2,4,6-trimethylbenzyl)imidazolidin-2-ylidene]ruthenium
    (Blackwell Publishing, 2005) Arslan, H; VanDerveer, D; Özdemir, I; Yasar, S; Çetinkaya, B
    In the title compound, [RuCl2(C24H26N2)], the multidentate ligand functions as both an arene and a carbene, and occupies four coordination sites. The two Cl atoms complete a distorted octahedron about the Ru atom.
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    First ruthenium complexes with a chelating arene carbene ligand as catalytic precursors for alkene metathesis and cycloisomerisation
    (Royal Soc Chemistry, 2001) Çetinkaya, B; Demir, S; Özdemir, I; Toupet, L; Sémeril, D; Bruneau, C; Dixneuf, PH
    Electron-rich carbene precursors 2 and 3, containing the imidazolidin-2-ylidene moiety with one (2) and two (3) pendent N-(2,4,6-trimethylbenzyl) groups, on reaction with [RuCl2(arene)](2) lead to ruthenium(II) complexes 5 and 6 containing the chelating 8-electron mixed arene-carbene ligand; the X-ray diffraction crystal structure of RuCl2{eta (1)- CN[CH2(eta (6)-2,4,6-Me3C6H2)]CH2CH2N(CH2CH2OMe)} 6, was established. These complexes are precursors of the unstable ruthenium-allenylidene intermediates 7 and 8, but are active catalysts either for selective catalytic alkene metathesis or cycloisomerization, depending on the nature of the 1,6-diene.
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    Hydrolysis, polycondensation, and catalytic properties of Ru(II) complex of 3-4,5-dihydroimidazol-1-ylpropyltriethoxysilane
    (John Wiley & Sons Inc, 2001) Seçkin, T; Özdemir, I; Çetinkaya, B
    The preparation and measurements of some properties of organic-inorganic hybrid materials derived from Ru(II)-3-4,5-dihyroimidazol-1-yl-propyltriethoxysilane inside a polysiloxane network have been achieved. The hydrolysis and polycondensation of Ru(II)-3-4,5-dihyroimidazol-1-yl-propyltriethoxysilane were performed in different experimental conditions, producing a new organic-inorganic silica. The alkoxysilyl groups available were used for the construction of inorganic backbone by the sal-gel process, and the imidazole group was found suitable for incorporating Ru(II) by coordination. The coordination of metal complex is retained because there is no leaching from the metal complex containing gels. To ensure sufficient catalytic properties, a series of hybrid materials from tetraethoxysilane was prepared. These materials were identified and catalytic activities were tested for cyclization of (Z)-3-methylpent-2-en-4-yn-1-ol to 2,3-dimethylfuran. Heterogeneous Ru(II) catalyst can also be recycled and reused without significant loss of selectivity or activity. (C) 2001 John Wiley & Sons, Inc.
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    Improved palladium-catalyzed coupling reactions of aryl halides using saturated N-heterocarbene ligands
    (Elsevier Science Bv, 2004) Gürbüz, N; Özdemir, I; Demir, S; Çetinkaya, B
    The incorporation of saturated N-heterocyclic carbenes into palladium pre-catalysts gives high catalyst activity in the Suzuki coupling of aryl iodides, bromides and deactivated aryl chloride substrates, whereas the yield of the palladium catalyzed Heck reaction of deactivated aryl chlorides is negligible. The complexes were generated in the presence of Pd(OAc)(2) by in situ deprotonation of 1,3-dialkylimidazolinium salts LHX (1) which were characterized by conventional spectroscopic methods and elemental analyses. (C) 2003 Elsevier B.V. All rights reserved.
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    In situ generated 1-alkylbenzimidazole-palladium catalyst for the Suzuki coupling of aryl chlorides
    (Elsevier, 2005) Özdemir, I; Sahin, N; Gök, Y; Demir, S; Çetinkaya, B
    Six 1-alkylbenzimidazole have been prepared and characterized by conventional spectroscopic methods and elemental analyses. Novel in situ generated palladium-benzimidazole complexes, tested in the Suzuki coupling reaction between phenylboronic acid and several aryl chlorides showed excellent catalytic activity. (c) 2005 Elsevier B.V. All rights reserved.
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    In situ generated palladium catalysts bearing 1,3-dialkylperimidin-2-yline ligands for Suzuki reactions of aryl chlorides
    (Elsevier, 2004) Özdemir, I; Alici, B; Gürbüz, N; Çetinkaya, E; Çetinkaya, B
    Four new 1,3-dialkylperimidinium halides have been prepared and characterized. The in situ prepared three component system Pd(OAc)(2)/1,3-dialkylperimidinium (1a-d) and Cs2CO3 catalyses the Suzuki cross-coupling of deactivated aryl chloride substrates in excellent yields under mild conditions. (C) 2004 Elsevier B.V. All rights reserved.
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    In situ generated rhodium-based catalyst for addition of phenylboronic acid to aldehydes
    (Wiley-Hindawi, 2005) Yigit, M; Özdemir, I; Çetinkaya, E; Çetinkaya, B
    New 1,3-dialkylperhydrobenzimidazolinium and 1,3-dialkylimidazolinium salts (2,4) as NHC precursors have been synthesized and characterized. These salts in combination with [RhCl(COD)](2) provided active catalysts for the addition of phenylboronic acid to aldehydes under mild conditions. The in situ prepared three-component system [RhCl(COD)](2)/imidazolinium salts (2,4) and KOBu' catalyse the addition of phenylboronic acid to sterically hindered aldehydes affording the corresponding arylated secondary alcohols in good yields. (c) 2005 Wiley Periodicals, Inc.
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    In situ preparation of palladium N-heterocyclic carbene complexes and use for Suzuki reaction
    (Wiley, 2005) Özdemir, I; Gök, Y; Gürbüz, N; Çetinkaya, E; Çetinkaya, B
    The in situ prepared three component system Pd(OAc)(2), 1,3-dialkylbenzimidazolium halides (1a-e) and t-BuOK catalyses quantitatively the Suzuki cross-coupling of deactivated aryl chloride substrates. 1,3-Dialkylbenzimidazolium salts (1a-e) were characterized by conventional spectroscopic methods and elemental analyses.
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    In-situ generated 1-alkylimidazoline-palladium catalyst for the Suzuki cross-coupling reaction of aryl chlorides
    (Taylor & Francis Inc, 2005) Özdemir, I; Sahin, N; Gürbüz, N; Demir, S; Gök, Y; Çetinkaya, B; Getinkaya, E
    Five 1-alkyimidazoline (1-5) have been prepared and characterized by conventional spectroscopic methods and elemental analyses. New in situ generated palladium-imidazoline complexes were tested for catalytic activity in the Suzuki coupling reaction between phenylboronic acid and several aryl chlorides.
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    In-situ generated functionalized benzimidazol-2-ylidene-palladium catalyst for Suzuki reaction
    (Polish Chemical Soc, 2004) Özdemir, I; Gök, Y; Gürbüz, N; Yasar, S; Çetinkaya, E; Çetinkaya, B
    From readily available starting materials functionalized 1,3-dialkylbenzimidazolium salts (la-g) have been prepared and characterized by conventional spectroscopic methods and elemental analysis. The in situ prepared three component system Pd(OAC)(2)/1,3-dialkylbenzimidazolium halides (1a-g) and Cs2CO3 catalyses Suzuki cross-coupling of aryl chloride substrates. These concepts for making catalysts in situ open the way for the discovery of many new catalysts via the interaction of commercially available metal complexes and suitable electron releasing ligands.
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    Novel N-heterocyclic-carbene-rhodium complexes as hydrosilylation catalysts
    (Elsevier, 2005) Yigit, M; Özdemir, I; Çetinkaya, B; Çetinkaya, E
    Novel rhodium-1,3-dialkylperhydrobenzimidazolin-2-ylidene (2a,b) and 1,3-dialkylimidazolin-2-ylidene complexes (4a,b) have been prepared and characterized by C, H, N analysis, H-1 NMR and C-13 NMR. Triethylsilane reacts with acetophenone derivatives in the presence of catalytic amount of the new rhodium(I)-carbene complexes, RhCl(COD)(1,3-dialkylperhydrobenzimidazolin-2-ylidene) or RhCl(COD)(1,3-dialkylimidazolin-2-ylidene) to give the corresponding silylethers in good yields (63-99%). (c) 2005 Elsevier B.V. All rights reserved.
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    Novel rhodium-1,3-dialkyl-3,4,5,6-tetrahydropyrimidin-2-ylidene complexes as catalysts for arylation of aromatic aldehydes
    (Elsevier Science Sa, 2005) Özdemir, I; Demir, S; Çetinkaya, B; Çetinkaya, E
    Six new rho dium-tetrahydropyrimidin-2-ylidene complexes (2a-f) have been prepared and characterized by C, H, N analysis, H-1 NMR and C-13 NMR. Phenylboronic acid reacts with aldehydes in the presence of a catalytic amount of the new rhodium(l)-carbene complexes, RhCl(COD)(1,3-dialkyl-3,4,5,6-tetrahydropyrimidin-2-ylidene), (2a-f), to give the corresponding secondary aryl alcohols in good yields (72-96%). (c) 2005 Elsevier B.V. All rights reserved.