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    1,3-Bis(2-thienylmethyl)-4,5-dihydroimidazolium trichlorido(?6-p-cymene) ruthenate(II)
    (Int Union Crystallography, 2009) Arslan, Hakan; VanDerveer, Don; Ozdemir, Ismail; Gurbuz, Nevin; Gok, Yetkin; Cetinkaya, Bekir
    The asymmetric unit of the title compound, (C13H15N2S2)-[RuCl3(C10H14)], contains a 1,3-(2-thienylmethyl)-4,5-dihydroimidazolium cation and a trichlorido(eta(6)-p-cymene)ruthenate(II) anion. The thiophene rings of the cation are disordered by an 180 degrees rotation about the thiophene-CH2 bonds with occupancies of 0.847 (5)/0.153 (5) and 0.700 (5)/0.300 (5), respectively. The Ru atom exhibits a distorted octahedral coordination with the benzene ring of the p-cymene ligand formally occupying three sites and three Cl atoms occupying the other three sites. The short C-N bond lengths in the imidazoline ring indicate partial electron delocalization within the N-C-N fragment. Cation and anions are connected through five intermolecular C-H center dot center dot center dot Cl hydrogen bonds and one C-H center dot center dot center dot pi hydrogen bond, forming a three-dimensional hydrogen-bonded network.
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    1,3-Bis(4-tert-butylbenzyl)-4,5-dihydroimidazolium chloride monohydrate
    (Int Union Crystallography, 2009) Arslan, Hakan; VanDerveer, Don; Yasar, Sedat; Ozdemir, Ismail; Cetinkaya, Bekir
    In the title compound, C25H35N2+center dot Cl-center dot H2O,the imidazolidine ring adopts a twisted conformation, with a pseudo-twofold axis passing through the N-C-N carbon and the opposite C-C bond. The N-C-N fragment of the imidazolidine ring shows some degree of both double- and single-bond character due to partial electron delocalization. One of the tert-butyl groups is disordered over two conformations with occupancies of 0.714 (8) and 0.286 (8). In the crystal, O-H center dot center dot center dot Cl and C-H center dot center dot center dot O hydrogen bonds help to establish the packing.
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    1,3-Bis(thiophen-2-ylmethyl)-3,4,5,6-tetrahydropyrimidinium trichlorido(?6-p-cymene)ruthenate(II)
    (Wiley-Blackwell, 2009) Arslan, Hakan; VanDerveer, Don; Ozdemir, Ismail; Gurbuz, Nevin; Gok, Yetkin; Cetinkaya, Bekir
    The asymmetric unit of the title compound, (C14H17N2S2)-[Ru(C10H14)Cl-3], contains a 1,3-bis(thiophen-2-ylmethyl)-3,4,5,6-tetrahydropyrimidinium cation and a trichlorido(eta(6)-p-cymene) ruthenate(II) anion. The Ru atom exhibits a distorted octahedral coordination with the benzene ring of the p-cymene ligand formally occupying three sites and three chloride atoms occupying the other three sites. The N-C bond lengths of the N-C-N unit of the pyrimidinium cation are shorter than the average single C-N bond length of 1.48 angstrom, thus showing double-bond character, indicating a partial electron delocalization within the N-C-N fragment. The pyrimidine ring has an envelope conformation. Four intermolecular C-H center dot center dot center dot Cl hydrogen bonds generate a three-dimensional hydrogen-bonded framework.
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    1,3-Bis[4-(dimethylamino)benzyl]-4,5,6,7-tetrahydro-1H-1,3-diazepan-2-ium chloride
    (Wiley-Blackwell, 2009) Arslan, Hakan; VanDerveer, Don; Gok, Yetkin; Ozdemir, Ismail; Cetinkaya, Bekir
    The title N-heterocyclic carbene derivative, C23H33N4+center dot Cl-, has been synthesized and characterized by elemental analysis, H-1 and C-13 NMR, IR spectroscopy and a single-crystal X-ray diffraction study. Ions of the title compound are linked by three C-H center dot center dot center dot Cl interactions. The seven-membered 1,3-diazepane ring has a form intermediate between twist-chair and twist-boat.
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    1-(1H-Benzimidazol-1-ylmethyl)-3-[2-(diisopropylamino)ethyl]-1H-benzimidazolium bromide 0.25-hydrate
    (Int Union Crystallography, 2009) Arslan, Hakan; VanDerveer, Don; Demir, Serpil; Ozdemir, Ismail; Cetinkaya, Bekir
    The title N-heterocyclic carbene derivative, C23H30N5+center dot Br-center dot 0.25H(2)O, was synthesized using microwave heating and was characterized by H-1 and C-13 NMR spectroscopy and a single-crystal X-ray diffraction study. The structure of the title compound are stabilized by a network of intra-and intermolecular C-H center dot center dot center dot Br hydrogen-bonding interactions. The crystal structure is further stabilized by pi-pi stacking interactions between benzene and imidazole fragment rings of parallel benzo[d] imidazole rings, with a separation of 3.486 (3) angstrom between the centroids of the benzene and imidazole rings. There is also an intermolecular C-H center dot center dot center dot pi interaction in the crystal structure. The C-N bond lengths for the central benzimidazole ring are shorter than the average single C-N bond, thus showing varying degrees of double-bond character and indicating partial electron delocalization within the C-N-C-N-C fragment. The isopropyl group is disordered over two sites with occupancies of 0.792 (10) and 0.208 (10).
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    1-(2-Phenylbenzyl)-3-(2,4,6-trimethylbenzyl)imidazolidinium bromide
    (Wiley-Blackwell Publishing, Inc, 2009) Arslan, Hakan; VanDerveer, Don; Yasar, Sedat; Ozdemir, Smail; Cetinkaya, Bekir
    In the title salt, C(26)H(29)N(2)(+)center dot Br(-),which may serve as a precursor for N-heterocyclic carbenes, the imidazolidine ring adopts a twist conformation with a pseudo-twofold axis passing through the N-C-N carbon and the opposite C-C bond. The N-C-N bond angle [113.0 (4)degrees] and C-N bond lengths [1.313 (6) and 1.305 (6) angstrom] confirm the existence of strong resonance in this part of the molecule. In the crystal, a C-H center dot center dot center dot Br interaction is present. The dihedral angle between the biphenyl rings is 64.3 (2)degrees and the phenyl rings make angles of 76.6 (3) and 18.5 (3)degrees with the plane of the imidazolidine ring.
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    1-(4-tert-Butylbenzyl)-3-(3,4,5-trimethoxybenzyl)benzimidazolium bromide monohydrate
    (Wiley-Blackwell Publishing, Inc, 2009) Arslan, Hakan; VanDerveer, Don; Demir, Serpil; Ozdemir, Ismail; Cetinkaya, Bekir
    A novel N-heterocyclic carbene derivative, C(28)H(33)N(2)O(3)(+)center dot-Br(-)center dot H(2)O, was synthesized and characterized by elemental analysis, (1)H and (13)C-NMR and IR spectroscopy and a single-crystal X- ray diffraction study. Ions of the title compound are linked by pi center dot center dot center dot pi stacking interactions (face-face separation 3.441 angstrom) and C-H center dot center dot center dot Br and O-H center dot center dot center dot Br interactions. Intra- and intermolecular C-H center dot center dot center dot O interactions are also present. The C-N bond lengths for the compound [1.329 (3), 1.325 (3), 1.389 (3) and 1.391 (3) angstrom] are all shorter than the average single C-N bond length of 1.48 angstrom, thus showing varying degrees of double-bond character.
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    2-(4-Pyridyl)-1,3-di(4-picolyl)imidazolidine
    (Mdpi, 2010) Yigit, Beyhan; Yigit, Murat; Ozdemir, Ismail; Cetinkaya, Bekir; Cetinkaya, Engin
    The title compound was prepared by treatment of N,N'-di(4-picolyl-amino) ethane with N,N-dimethylformamide dimethylacetal in toluene and it was characterized by elemental analysis, H-1 NMR and C-13 NMR.
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    Benzimidazol-2-ylidene ruthenium complexes for C-N bond formation through alcohol dehydrogenation
    (Tubitak Scientific & Technological Research Council Turkey, 2023) Nawaz, Zahid; Gurbuz, Nevin; Zafar, Muhammed naveed; Ozdemir, Namik; Cetinkaya, Bekir; Ozdemir, Ismail
    A low temperature hydrogen borrowing approach to generate secondary amines using benzimidazole-based N-heterocyclic carbene (BNHC) ruthenium complexes is reported. A series of the piano-stool complexes of the type [(eta 6-p-cymene)(BNHC)RuCl2] (1a-g) were synthesized via one-pot reaction of the NHC salt precursor, Ag2O, and [RuCl2(p-cymene)]2 and characterized using con-ventional spectroscopic techniques. The geometry of two precursors, [(eta 6-p-cymene)(Me4BnMe2BNHCCH2OxMe)RuCl2] (1f) and [(eta 6-p-cymene)(Me5BnMe2BNHCCH2OxMe)RuCl2] (1g), was studied by single crystal X-ray diffraction. These catalysts were found to dehydrogenate alcohols efficiently at temperatures as low as 50 degrees C to allow Schiff-base condensation and subsequent imine hydrogenation to afford secondary amines. Notably, this ruthenium-based procedure enables the N-alkylation of aromatic and heteroaromatic primary amines with a wide range of primary alcohols in excellent yields of up to 98%. The present methodology is green and water is liberated as the sole byproduct.
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    Benzylic imidazolidinium, 3,4,5,6-tetrahydropyrimidinium and benzimidazolium salts
    (Wiley-V C H Verlag Gmbh, 2008) Yasar, Sedat; Oezdemir, Ismail; Cetinkaya, Bekir; Renaud, Jean-Luc; Bruneau, Christian
    Imidazoliidinium, tetrahydropyrimidinium and benzimidazolium. salts were prepared. Upon reaction with tBuOK, they generate carbene ligands, which were associated in situ to [RuCp*(MeCN)(3)]PF6 to produce ruthenium catalysts that are active for the substitution of allylic substrates by dimethyl of the N-heterocyclic structures, as well as that of the benzyhc N-substituents, on the reactivity and regioselectivity were examined. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).
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    Bromido[1-(?6-4-tert-butylbenzyl)-3-(2,4,6-trimethylbenzyl)benzimidazol-2-ylidene]chloridoruthenium(II)
    (Wiley-Blackwell, 2009) Arslan, Hakan; VanDerveer, Don; Ozdemir, Ismail; Demir, Serpil; Cetinkaya, Bekir
    A new ruthenium complex, [RuBrCl(C28H32N2)], has been synthesized and characterized by elemental analysis, H-1 NMR, C-13 NMR, IR-spectroscopy and a single-crystal X-ray diffraction study. The Ru atom in this complex is best described as having a considerably distorted octahedral coordination environment with the arene occupying three coordination sites. Two further coordination sites are occupied by chloride and bromide ligands, while the sixth site is occupied by the carbene. The carbene portion of the ligand is a benzimidazole ring. This ring is connected to the C6H4C(CH3)(3) arene by a CH2 bridge. This leads to a system with very little apparent strain. The two halogen atoms are disordered between Br and Cl. Two partial Cl atoms share the same sites as two partial Br atoms so that the title compound effectively has one Cl and one Br atom. C-H center dot center dot center dot X (X = Cl, Br) hydrogen bonds help to stabilize the crystal structure.
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    Dichloride [1-(2,4,6-trimethylbenzyl)-3-(biphenyl-2-ylmethyl)-imidazolidin-2-ylidine (?6-hexamethylbenzene)]ruthenium
    (Tubitak Scientific & Technological Research Council Turkey, 2006) Arslan, Hakan; Van Derveer, Donald; Ozdemir, Ismail; Yasar, Sedat; Cetinkaya, Bekir
    The single crystal X-ray structure of the imidazolidin ruthenium complex, C38H46N2Cl2Ru, was determined. The complex is an orthorhombic space group Pbca with a = 17.3586(32) angstrom, b = 14.4447(27) angstrom, c = 27.4325(52) angstrom, and V = 6878.466(4) angstrom(3) with Z = 8 for D-calc = 1.357 g/cm(3). It exhibits the expected 3-legged piano stool geometry. There is one coordination bond of the ruthenium atom with the electrons of the eta(6)-hexamethylbenzene, 2 symmetrical Ru-Cl bonds, and one Ru-C bond involving the imidazole ring. The coordination around the ruthenium atom is 4-fold, which in this is case is pseudo-tetrahedral.
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    Dichlorido[1-(2-methylbenzyl)-3-(?6-2,4,6-trimethylbenzyl)-1H-2,3-dihydrobenzimidazol-2-ylidene]ruthenium(II) dichloromethane solvate
    (Wiley-Blackwell, 2009) Arslan, Hakan; VanDerveer, Don; Yasar, Sedat; Ozdemir, Ismail; Cetinkaya, Bekir
    The title complex, [RuCl2(C25H26N2)]center dot CH2Cl2, is best thought of as containing an octahedrally coordinated Ru center with the arene occupying three sites. Two Ru-Cl bonds and one Ru-carbene bond complete the distorted octahedron. The carbene portion of the ligand is a benzimidazole ring. This ring is connected to the C6H2(CH3)(3) arene group by a CH2 bridge. This leads to a system with very little apparent strain. A dichloromethane solvent molecule completes the crystal structure. Further stabilization is accomplished via C-center dot center dot center dot N and C-H center dot center dot center dot Cl interactions.
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    Direct arylation of arene C-H bonds by cooperative action of NHCarbene-Ruthenium(II) catalyst and carbonate via proton abstraction mechanism
    (Amer Chemical Soc, 2008) Ozdemir, Ismail; Demir, Serpil; Cetinkaya, Bekir; Gourlaouen, Christophe; Maseras, Feliu; Bruneau, Christian; Dixneuf, Pierre H.
    Direct functionalization of sp(2) C-H bonds via ortho diarylation of 2-pyridyl benzene with arylbromides was achieved using ruthenium(II) catalysts containing a RuCl2(NHC) unit and generated from [RuCl2(arene)](2) and two types of NHC precursors, pyrimidinium and benzimidazolium salts, in the presence of Cs2CO3. DFT calculations from RuCl2(NHC)(2-pyridylbenzene) show that a proton abstraction mechanism, on cooperative actions of both the coordinated base and the Ru(II) center, is favoured via a 13.7 kcal mol(-1) exothermic process affording an orthometalated intermediate with a 2.009 angstrom Ru-C bond.
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    Heck and suzuki reactions of aryl halides catalyzed by 1,3-dialkylimidazolinium/palladium
    (Science Press, 2008) Yasar, Sedat; Oezdemir, Ismail; Cetinkaya, Bekir
    New, sterically demanding 1,3-dialkylimidazolinium salts used as N-heterocyclic carbene precursors were synthesized and characterized. These salts, combined with palladium acetate, provided active catalysts for Heck and suzuki cross-coupling of aryl chlorides and bromides under mild conditions.
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    In situ catalytic activities of 1,3-dialkyltetrahydropyrimidinium salts/[RuCl2(p-cymene)]2 system for transfer hydrogenation reactions
    (Tubitak Scientific & Technological Research Council Turkey, 2011) Ozcan, Emine Ozge; Mercan, Deniz; Gurbuz, Nevin; Cetinkaya, Engin; Cetinkaya, Bekir; Ozdemir, Ismail
    Hydrogen-transfer reduction processes are attracting increasing interest from synthetic chemists in view of their operational simplicity. In the present study novel ruthenium carbene complexes were generated in situ and tested for their transfer hydrogenation reactions. The in situ prepared 3 component 1,3-dialkyltetrahydropyrimidinium salts (LHX)/[RuCl2(p-cymene)](2) and KOH catalyzed quantitatively the transfer hydrogenation of ketones under mild reaction conditions in 2-propanol.
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    N-functionalized azolin-2-ylidene-palladium-catalyzed Heck reaction
    (Wiley-Hindawi, 2008) Ozdemir, Ismail; Gurbuz, Nevin; Gok, Yetkin; Cetinkaya, Bekir
    Novel 1,3-dialkylimidazolidinium, 1,3-dialkyl-3,4,5,6-tetrahydropyrimidinium, and 1,3-dialkyl-1H-4,5,6,7-tetrahydrodiazepinium hexafluorophosphates (la-c, 2a-c) as N-heterocyclic carbene precursors have been synthesized and characterized. The incorporation of saturated N-heterocyclic carbenes into palladium precatalysts gives high-catalyst activity in the Heck coupling of aryl bromide substrates in aqueous media. The complexes were generated in the presence of Pd(OAC)(2) by in situ deprotonation of 1,3-dialkylazolinium salts 1, 2. (C) 2008 Wiley Periodicals, Inc.
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    New 1,2,4,5-tetrakis-(N-imidazoliniummethyl)benzene and 1,2,4,5-tetrakis(N-benzimidazoliummethyl)benzene salts as N-heterocyclic tetracarbene precursors: synthesis and involvement in ruthenium-catalyzed allylation reactions
    (Pergamon-Elsevier Science Ltd, 2010) Gurbuz, Nevin; Demir, Serpil; Ozdemir, Ismail; Cetinkaya, Bekir; Bruneau, Christian
    New tetraimidazolinium and tetrabenzimidazolium salts have been prepared Upon reaction with (BuOK)-Bu-t. they generate carbene ligands, which were associated in situ to [RuCp'(MeCN)(3)]PF6 to produce new ruthenium catalysts that are active for the Substitution of allylic substrates by amines, phenols, and carbonucleophiles The influence of the N-heterocyclic core as well as that of the N-substitutents at the periphery of the salts, on reactivity and regioselectivity have been exammed (C) 2009 Elsevier Ltd All rights reserved
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    New Functionalized N-Heterocyclic Carbene Ligands for Arylation of Benzaldehydes
    (Wiley, 2009) Dogan, Oznur; Gurbuz, Nevin; Ozdemir, Ismail; Cetinkaya, Bekir
    Novel functionalized 1,3-dialkylimidazolinium salts (LHCl) as NHC precursors have been prepared and successfully applied in palladium-catalyzed arylation of benzaldehydes. The ortho position of aromatic aldehydes was directly and selectively arylated with aryl chlorides in the presence of a catalytic system prepared in situ from Pd(OAC)(2), 1,3-dialkylimidazolinium chlorides (2a-c), and CS2CO3.
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    Palladium Complexes with Tetrahydropyrimidin-2-ylidene Ligands: Catalytic Activity for the Direct Arylation of Furan, Thiophene, and Thiazole Derivatives
    (Amer Chemical Soc, 2015) Karaca, Emine Ozge; Gurbuz, Nevin; Ozdemir, Ismail; Doucet, Henri; Sahin, Onur; Buyukgungor, Orhan; Cetinkaya, Bekir
    The synthesis and characterization of novel 1,3-benzyl-3,4,5,6-tetrahydropyrimidin-2-ylidene-based N-hetero-cyclic carbene palladium(II) complexes (1a-d) were described. The crystal structure of trans-dichlorobis[1,3-bis(4-methylbenzyl)-3,4,5,6-tetrahydropyrimidin-2-ylidend- palladium(II) was presented. Pd(II) complexes 1a-d were tested as catalysts in the direct C5 or C2 arylation of furans, thiophenes, and thiazoles, with various aryl bromides at 150 degrees C for 1 h. These complexes exhibited moderate to high catalytic activities under the given conditions.