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Öğe 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, IsmailA 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.Öğe Benzimidazole-based N-heterocyclic carbene silver complexes as catalysts for the formation of carbonates from carbon dioxide and epoxides(Elsevier, 2022) Nawaz, Zahid; Ullah, Habib; Gurbuz, Nevin; Zafar, Muhammad Naveed; Verpoort, Francis; Tahir, Muhammad Nawaz; Ozdemir, IsmailA series of left-to-right inequivalent 1,3-disubstituted benzimidazolium halide pro-ligands having the general formula [(BNHCCH2OxMe)-B-R][X] (R = 3-Me-Bn, 3,5-Me-2-Bn, 2,4,6-Me-3-Bn, 2,3,5,6-Me-4-Bn, 2,3,4,5,6-Me-5-Bn, 3,4,5-(OMe)(3)-Bn, or 4-Bu-t-Bn; X = Cl, Br) were synthesized by the alkylation of 1-((3-methyloxetan-3-yl)methyl)benzimidazole. The corresponding Ag complexes, ((BNHCCH2OxMe)-B-R) AgX, were prepared following pro-ligand addition to Ag2O. These compounds were characterized using spectroscopic techniques such as FT-IR, NMR spectroscopy, and single-crystal X-ray diffraction. The solid-state structure of ((3-Me-BnBNHCCH2OxMe))AgCl revealed a linear monomer while [((2,4,6-Me3-BnBNHCCH2OxMe))AgCl](2) was found to exist as a dimer with pseudo trigonal planar geometry about each metal center. The synthesized ((BNHCCH2OxMe)-B-R)AgX complexes were found to be efficient for the addition of carbon dioxide to epoxides to yield value-added cyclic carbonates at ambient pressure. Amongst the investigated complexes, the bimetallic complex [((2,4,6-Me3-BnBNHCCH2OxMe))AgCl](2) was found to be the most active for CO2 insertion, exhibiting favorable activity when compared to known NHC complexes.Öğe Design of efficient benzimidazole-derived N- heterocyclic carbene Ag(I) catalysts for aldehyde -amine -alkyne coupling(Elsevier, 2024) Nawaz, Zahid; Gurbuz, Nevin; Zafar, Muhammad Naveed; Tahir, Muhammad Nawaz; Ozdemir, Ismail; Trovitch, Ryan J.A mild catalytic protocol for aldehyde, amine, and alkyne coupling (A3-coupling) allows for the selective synthesis of propargyl amines using 5,6-dimethylbenzimidazole-derived N-heterocyclic carbene (BNHC) silver(I) catalysts. A series of BNHC Ag(I) halide complexes were synthesized and their structures have been elucidated through the use of multinuclear NMR and FT-IR spectroscopy. Furthermore, the pseudo-linear geometry of two different compounds was substantiated by single-crystal X-ray diffraction. Silver-based A3-coupling was achieved for both acyclic and cyclic secondary amines using a diverse set of alkynes to afford propargyl amines with yields of up to 95 %. The present approach is environmentally benign and water is generated as the sole byproduct.Öğe Direct arylation (hetero-coupling) of heteroarenes via unsymmetrical palladium-PEPPSI-NHC type complexes(Pergamon-Elsevier Science Ltd, 2021) Nawaz, Zahid; Gurbuz, Nevin; Zafar, Muhammad Naveed; Tahir, Muhammad Nawaz; Ashfaq, Muhammad; Karci, Huseyin; Ozdemir, IsmailThe growing interest of industry in the field of bi(hetero)arenes compounds, motivated us to synthesize these compounds via homogeneous catalytic route by using Pd PEPPSI-type complexes through direct arylation. In this work, the five new Pd PEPPSI-type complexes bearing NHC spectator ligands were synthesized and characterized by a bunch of spectroscopic techniques. Further confirmations of structural details were provided by a single crystal X-ray diffraction study of one pro-ligand and one complex. All these newly synthesized Pd-carbene complexes were found significantly active as catalysts toward direct arylation of five members heterocyclic compounds such as n-propylthaizole, 2-acetylfurane and 2-acetylthiophene with aryl bromides derivatives. These catalysts give significantly good results within two hours with just 1 mol % catalyst loading.Öğe Synthesis of new Pd(NHC)-PEPPSI type complexes as catalysts toward C-C cross-coupling reactions(Elsevier, 2021) Nawaz, Zahid; Gurbuz, Nevin; Zafar, Muhammad Naveed; Ozdemir, Namik; Habib, Uzma; Jan, Kalsoom; Ozdemir, IsmailThe goal of our research is to synthesis homogeneous catalysts, for which we take start from two novel precursors of 1-(3-methyloxetane-3-yl)benzimidazole and 5,6-dimethyl-1-((3-methyloxetane3-yl)benzimidazole. A series of ligands containing 1,3-disubstituted benzimidazolium salts were synthesized from the corresponding precursors to form N-heterocyclic carbene (NHC) ligands. Furthermore, four new Pd(NHC)-PEPPSI type complexes were synthesized from these ligands. The structure elucidation of all the synthesized ligands, and complexes was confirmed by various spectroscopic techniques such as NMR, FT-IR. The compounds 1b, 2b, 3a, 3d were confirmed by the X-ray technique. All these complexes were found significantly active as catalysts toward the C-C cross-coupling reaction. (c) 2021 Elsevier B.V. All rights reserved.Öğe Sythesis, characterisation, anticancer and antimicrobial activity of Ag-N-heterocyclic carbene complexes containing benzimidazole derivatives(Elsevier Science Sa, 2024) Karci, Huseyin; Dundar, Muhammed; Nawaz, Zahid; Ozdemir, Lknur; Gurbuz, Nevin; Koc, Ahmet; Ozdemir, IsmailTo prepare a novel series of silver(I) complexes, the interaction of benzimidazolium salts having their two nitrogen atoms substituted by bulky groups with Ag2O in DCM has been carried out. Their structures were characterized by elemental analyses, 1H NMR, 13C NMR, elemental analysis, and IR spectroscopy techniques. Further, the antimicrobial and antifungal activities properties of both the salts and their silver(I)-NHC complexes were tested against positive and negative bacteria using the Clinical and Laboratory Standards Institute (CLSI) and the European Committee for Antimicrobial Susceptibility Testing (EUCAST) respectively. The results show that silver complexes are effective against E. coli, P. aeruginosa and S. aureus bacterial species with moderate to high activity, and their minimum inhibitory concentrations ranging from 25 to 400 mu g/Ml. It was also observed that 3b compound, which has the best antifungal properties among the synthesized compounds, showed high antimicrobial activity when all bacterial species were taken into account. In addition, the salts and complexes were then evaluated for their ability to inhibit the proliferation of four different cancer cell lines (A549, MCF-7, HCT116, SH-SY5Y and BEAS-2B cells lines). AlamarBlue assay demonstrated that the salts and complexes exhibited potent cytotoxicity towards all cancer lines. 2c compound showed the highest cytotoxic activity against BEAS-2B, A549 and MCF-7 cell lines. Except for 2c, compounds 3d, 3e and 3f showed cytotoxic activity at the lowest concentrations against MCF7 cell line.The study highlights the importance of N-heterocyclic carbene ligands in the development of silver-based drugs with anticancer properties.
