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Öğe Antimicrobial activity of rhodium (I) and ruthenium (II) carbene complexes derived from benzimidazole against staphylococcus aureus isolates(Turkish Journal of Medical Sciences, 1997) Durmaz, Rıza; Küçükbay, Hasan; Çetinkaya, Engin; Çetinkaya, BekirAbstract: As an extension of our previous study, three benzimidazole derivatives and one benzothiazolium salt found to be significantly effective against Staphylococcus aureus (ATCC 29213) were evaluated for their in vitro antimicrobial activity againts 98 Staphylococcus strains isolated from the nasal swabs of hospital staff (68) and clinical specimens (30). The previously snthesized compounds, referred to as 1, 2, 3 and 4, were found to be effective at the average minimal inhibitory concentrations (MICs) of 5.8, 5.5, 18.5 and 15.8 µg/mL, respectively. The resuts of this study show the activity of compounds 1 and 2 against staphylococci to be noteworthy.Öğe Bazı benzimidazol, imidazol ve benzotiyazol türevlerinin in vivo MIC değerleri ile böbrek ve karaciğer fonksiyon testleri ile etkilerinin araştırılması(1997) Durmaz, Rıza; Küçükbay, Hasan; Çetinkaya, Engin; Çetinkaya, Bekir; Günal, SelamiDaha önceki çalışmalarımızda çok sayıda benzimidazol, imidazol ve benzotiyazol türevleri sentez edilerek in vitro şartlarda antimikrobiyal aktiviteleri test edildi. Bileşiklerden dört tanesinin standart ve klinik suşlara karşı minimum inhibitor konsantrayonları (MIC) 5-25 $mu$ g/mL arasında bulundu. En fazla etkili bulunan bu bileşiklerin terapötik amaçla kullanılıp kullanılamayacağına karar verebilmek için serum MIC değerleri ve karaciğer ile böbrek fonksiyonlarına etkileri araştırıldı. In vivo çalışmalarda bir nolu bileşik damar içi, kas içi ve oral yolla; 2, 3 ve 4 nolu bileşikler ise oral ve damar içi yolla farklı konsantrasyonlarda Wistar türü sıçanlara verildi. Madde verildikten 4 ve 24 saat sonra kan alınarak biyoanaliz yöntemiyle serum MIC değerleri ve otoanalizör yardımıyla biyokimyasal parametreler çalışıldı, karaciğer ve böbrekten histolojik inceleme yapıldı. Denemelerin hiç birinde bileşikler serumda MIC değerine ulaşamamıştır. Biyokimyasal parametrelerden kreatinin bütün denemelerde, kan üre azotu seviyeleri ise iki madde ile ilgili bazı denemeler dışında normal, karaciğer fonksiyon testlerinden aspartat aminotransferaz ve/veya alanın aminotransferaz ve/veya alkalen fosfataz değerleri genellikle yüksek bulunmuştur. Elde edilen sonuçlardan, test edilen bileşiklerin karaciğer ve safra yollarında harabiyet oluşturdukları söylenebilir.Öğe Benzimidazolylidene carbene ligated palladium catalysis of the Heck reaction in aqueous media(Turkish Journal of Chemistry, 2007) Özdemir, İsmail; Gök, Yetkin; Gürbüz, Nevin; Çetinkaya, BekirYıl: 2007Cilt: 31Sayı: 4ISSN: 1300-0527Sayfa Aralığı: 397 - 402 Metin Dili: İngilizce Öz: Başlık (İngilizce): Öz (İngilizce): A highly effective, easy to handle and environmentally benign process for a palladium mediated Heck reaction was developed. The in situ prepared 3-component system, Pd(OAc)2/1,3-dialkylbenzimidazolium chlorides (LHX = 1a-g) and Cs2CO3, catalyzes quantitatively the Heck coupling of aryl bromides under mild conditions in aqueous media.Öğe Cross coupling reactions catalyzed by (NHC)Pd(II) complexes(TURKISH JOURNAL OF CHEMISTRY, 2015) Gürbüz, Nevin; Karaca, Emine Özge; Özdemir, İsmail; Çetinkaya, BekirThis review is focused on new developments reported during the last 3 years concerning the catalytic performances of in situ formed or preformed NHC Pd(II) complexes (NHC: N-heterocyclic carbene) for cross-coupling reactions such as Heck Mizoraki (often shortened to the Heck reaction), Kumada, Negishi, Suzuki Miyaura (often shortened to the Suzuki reaction), Sonogashira and Hiyama couplings, and the Buchwald-Hartwig aminations, which are extremely powerful in the formation of C-C and C-heteroatom bonds. Due to the great number of publications and limited space here, we made a special attempt to compile the relevant data in tables, which we hope will serve as a guide for chemists interested in these reactions. The syntheses of the precatalysts and the generally accepted reaction mechanisms are also briefly described.Öğe Dichloride [1-(2,4,6-trimethylbenzyl)-3-(biphenyl-2-ylmethyl)-imidazolidin-2-ylidine ( ?6 -hexamethylbenzene] ruthenium(2006) Arslan, Hakan; Derveer, Donald Van; Özdemir, İsmail; Yaşar, Sedat; Çetinkaya, BekirThe single crystal X-ray structure of the imidazolidin ruthenium complex, C38H46N2C2Ru, was determined. The complex is an orthorhombic space group Pbca with a = 17.3586(32) ˚A, b = 14.4447(27) ˚A, c = 27.4325(52) ˚A, and V = 6878.466(4) ˚A3 with Z= 8 for Dcalc= 1.357 g/cm3. It exhibits the expected 3-legged piano stool geometry. There is one coordination bond of the ruthenium atom with the electrons of the ?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.Öğe Dichloride [1-(2,4,6-trimethylbenzyl)-3-(biphenyl-2-ylmethyl)-imidazolidin-2-ylidine (\eta6-hexamethylbenzene] ruthenium(Turkish Journal of Chemistry, 2006) Arslan, Hakan; Derveer, Donald Van; Özdemir, İsmail; Yaşar, Sedat; Çetinkaya, BekirAbstract:The single crystal X-ray structure of the imidazolidin ruthenium complex, C38H46N2C2Ru, was determined. The complex is an orthorhombic space group Pbca with a = 17.3586(32) ˚A, b = 14.4447(27) ˚A, c = 27.4325(52) ˚A, and V = 6878.466(4) ˚A3 with Z= 8 for Dcalc= 1.357 g/cm3. It exhibits the expected 3-legged piano stool geometry. There is one coordination bond of the ruthenium atom with the electrons of the η6-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.Öğe In situ catalytic activities of 1,3-dialkyltetrahydropyrimidinium salts/[$RuCl_2(p-cymene)]_2$ system for transfer hydrogenation reactions(2011) Özcan, Emine Özge; Mercan, Deniz; Gürbüz, Nevin; Çetinkaya, Engin; Çetinkaya, Bekir; Özdemir, İsmailAbstract: 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)/[Öğe In situ catalytic activities of 1,3-dialkyltetrahydropyrimidinium salts/[RuCl_2(p-cymene)]_2 system for transfer hydrogenation reactions(Turkish Journal of Chemistry, 2011) Özcan, Emine Özge; Mercan, Deniz; Gürbüz, Nevin; Çetinkaya, Engin; Çetinkaya, Bekir; Özdemir, İsmailAbstract: 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.Öğe Synthesis of a ruthenium complex bound to a polyimide matrix: Investigating the catalytic properties in a hydrosilylation reaction(Turkish Journal of Chemistry, 2006) Seçkin, Turgay; Köytepe, Süleyman; Özdemir, İsmail; Çetinkaya, Bekir3,6-Bis(dimethylamino)acridine(hexamethylbenzene)dichlororuthenium(II) was used as a tricyclic heteroatomic monomer to prepare polyimides from the corresponding dianhyrides by solution condensation. The ruthenium complex monomer was synthesized starting from [RuCl2(HMB)]2 and 3- 6-bis(dimethylamino)acridine. The polymers had inherent viscosities of 1.77 to 2.11 and were soluble in most polar solvents. The glass transition temperatures were in the range of 204 to 298 ?C and the 10% weight loss in the range of 506-626 ?C, depending upon the structure of the dianhyride monomer. The catalytic activity of the polyimides tested in a hydrosilylation reaction of acetophenone was up to 90%. Leaching of ruthenium into the reaction mixture, found to be in the range of 60-75 ppm, was an indication of reduced catalyst bleeding. Key Words: Heterogeneous catalysis, Ruthenium, Polyimide, Hydrosilylation.Öğe Yeni molibden karben komplekslerinin sentezi(Fırat Üniversitesi Fen ve Mühendislik Bilimleri Dergisi, 2013) Gürbüz, Nevin; Özdemir, İsmail; Çetinkaya, BekirBu çalışmada molibdenin yeni N-heterosiklik karben kompleksleri sentezlendi. Karben kompleksleri Mo(CO)_6; ve elektronca zengin olefinlerden (l ve 2) elde edildi. Karben komplekslerinin yapıları {1}H-NMR, {13}C-NMR, FT-IR ve elementel analiz ile karakterize edildi.
