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Öğe Direct arylation of heteroarenes by PEPPSI-type palladium-NHC complexes and representative quantum chemical calculations for the compound which the structure was determined by X-ray crystallography(Taylor & Francis Ltd, 2019) Sahin, Neslihan; Serdaroglu, Goncagul; Dusunceli, Serpil Demir; Tahir, Muhammad Navaz; Arici, Cengiz; Ozdemir, IsmailIn this study, we synthesized five new PEPPSI-type Pd-NHC complexes with high yields around 78-83%. The structures of all complexes were characterized by FT-IR, H-1 NMR, and C-13{H-1} NMR spectroscopies. Further, the structure of 2c was determined by X-ray crystallography. The single-crystal structure of 2c shows that coordination geometry around Pd is distorted square planar. The Pd-NHC complexes were efficient catalysts for the direct C5-arylation of 2-n-butylthiazole, 2-n-butylfuran, and 2-n-butylthiophene with various aryl-bromides and showed high catalytic activity for arylation reaction using only 1 mol% catalyst loading at 130 degrees C for 1 h. The conversions for substrates containing electron-withdrawing groups were higher than for substituents containing electron-donating groups. In order to evaluate the catalytic activity of the complexes, representative electronic and spectroscopic simulations by DFT method have been performed for 2c. NBO analysis has revealed that the strongest interaction contributing to the lowering of the molecular stabilization energy for 2c is predicted as pi(C11-N27) -> pi*(N26-C28) with E-(2) = 73.93 kcal mol(-1). In addition, FMO analysis has implied that 2c is more chemically reactive because of its lower energy gap value. According to the other quantum chemical parameters, 2c is softer, better electrophile and has more charge-transfer capability than 1c.Öğe A novel ditopic ring-expanded N-heterocyclic carbene ligand-assisted Suzuki-Miyaura coupling reaction in aqueous media(Pergamon-Elsevier Science Ltd, 2017) Karaca, Emine Ozge; Akkoc, Mitat; Tahir, Muhammad Nawaz; Arici, Cengiz; Imik, Fatma; Gurbuz, Nevin; Yasar, SedatA series of seven-membered ditopic ring-expanded N-heterocyclic carbene (dre-NHC) precursors, bearing sterically demanding and electron-rich aryl groups, were synthesised in moderate yields via the reaction of 1,2,4,5-tetrakis(bromomethyl)benzene with the corresponding N,N'-diarylformamidines in the presence of K2CO3 in acetonitrile under an air atmosphere. All new compounds were characterised by HRMS, NMR spectroscopy, and microanalysis, as well as X-ray crystallography for compound lc. The development of an efficient catalytic system for the Suzuki-Miyaura coupling reaction of aryl chlorides with various boronic acids was also investigated using the in situ generated dre-NHC ligands. (C) 2017 Elsevier Ltd. All rights reserved.Öğe Novel N-heterocyclic carbene silver(I) complexes: Synthesis, structural characterization, and anticancer activity(Elsevier Science Sa, 2019) Bolukbasi, Serap Sahin; Sahin, Neslihan; Tahir, Muhammad Nawaz F.; Arici, Cengiz; Cevik, Esranur; Gurbuz, Nevin; Ozdemir, IsmailIn this study, we synthesized four novel unsymmetrically substituted NHC ligands (la-d) and their Ag(I) complexes (2a-d). All new compounds were characterized using elemental analysis, FT-IR, H-1 NMR, and C-13 NMR spectroscopy and X-ray crystallography. The molecular structure of complex 2d was elucidated through single crystal X-ray diffraction analyses. Single crystal structural studies for complex 2d show that the benzene rings (C9-C14) and the central benzimidazole ring system make dihedral angles of 85.65(11)degrees. The Ag-Cl and Ag-C single bond lengths are 2.3553(7) and 2.096(2)angstrom, respectively. The C-Ag-C/ bond angle is 168.27(7)degrees. Both salts and complexes were tested for their anti-cancer potential against three human cancer cell lines (DU-145, MCF-7, and MDA-MB-231) and non-cancer cells adipose from mouse (L-929) for 24 h, 48 h and 72 h using the MTT assays. However, the Ag(I)-NHC complexes (2a-d) showed a dose and time-dependent cytotoxic activity against all cell lines. MDA-MB-231 human breast carcinoma cells were the most sensitive to the Ag(I)-NHC complex displaying IC50 lower than 1 mu M all time points. Further, the IC(50)s for Ag(I)-NHC were higher in non-cancer cells, suggesting that complexes possessed noteworthy selectivity for human cancer cells.Öğe PEPPSI type complexes: Synthesis, x-ray structures, spectral studies, molecular docking and theoretical investigations(Pergamon-Elsevier Science Ltd, 2021) Serdaroglu, Goncagul; Sahin, Neslihan; Ustun, Elvan; Tahir, Muhammad Navaz; Arici, Cengiz; Gurbuz, Nevin; Ozdemir, IsmailIn this work, three novel potent benzimidazolium-derived PEPPSI type palladium complexes, namely dichloro[1-allyl-3-benzylbenzimidazole-2-ylidene]pyridine palladium(II) (1), dichloro[1-allyl-3-(1-naphthylmethyl)benzimidazole-2-ylidene]pyridine palladium(II) (2) and dichloro[1-allyl-3-(9-anthrylmethyl)benzimidazole-2-ylidene]pyridine palladium(II) (3), were synthesized and characterized by single X-ray crystallography, FT-IR and NMR spectroscopy. The results were compared with the relevant calculated data. After structural and spectroscopic determination, the performance of the global reactivity behavior of these derivatives was evaluated by quantum chemical parameters (QCP) obtained from DFT/B3LYP and HF methods utilized with the 6-311 g**/LANL2DZ basis set. Next, NBO analyses were conducted to enlighten the possible interactions that occur for each derivative and this revealed that the main role in the lowering of the stabilization energies of all the derivatives was sourced from n -> pi* and pi -> pi* interactions. Finally, all the complexes were analyzed for their anticancer potential by the molecular docking method with VEGFR (vascular endothelial growth factor receptor), thioredoxin reductase, breast cancer and the dodecamer structure of DNA. (C) 2021 Elsevier Ltd. All rights reserved.Öğe Synthesis of N-heterocyclic carbene-palladium-PEPPSI complexes and their catalytic activity in the direct C-H bond activation(Elsevier Science Sa, 2018) Kaloglu, Nazan; Kaloglu, Murat; Tahir, Muhammad Nawaz; Arici, Cengiz; Bruneau, Christian; Doucet, Henri; Dixneuf, Pierre H.A series of benzimidazolium salts having their two nitrogen atoms substituted by bulky groups have been synthesized. The benzimidazolium salts were readily converted into the corresponding palladium-NHC-PEPPSI complexes with general formula [PdBr2(NHC) (Py)], (NHC = N-heterocyclic carbene; PEPPSI = pyridine-enhanced precatalyst preparation, stabilisation, and initiation). The structures of all new compounds were characterized by NMR, IR spectroscopy and microanalysis techniques, which support the proposed structures. The molecular structure of complex 2g was determined by singlecrystal X-ray diffraction study. Next, the palladium-NHC-PEPPSI complexes were used as catalysts in the direct C5-arylation of 1-methylpyrrole-2-carboxaldehyde by aryl halides. These complexes exhibited moderate to high catalytic activities and gave C-H activation selectively at the C5-position of 1methylpyrrole- 2-carboxaldehyde. Both electron-donating and electron-withdrawing substituents were well tolerated with catalytic systems based on these complexes, even non-activated aryl chlorides such as chlorobenzene or 4-chlorotoluene were coupled with pyrrole in moderate yields. (C) 2017 Elsevier B.V. All rights reserved.Öğe Synthesis, characterization and anticancer activity of allyl substituted N-Heterocyclic carbene silver(I) complexes(Elsevier Science Bv, 2019) Sahin, Neslihan; Sahin-Bolukbasi, Serap; Tahir, Muhammad Nawaz; Arici, Cengiz; Cevik, Esranur; Gurbuz, Nevin; Ozdemir, IsmailMetal N-heterocyclic carbene (NHC) complexes have attracted considerable attention in biological fields for their potential applications in cancer and antimicrobial therapies. In this study, four new benzimidazole-based N-heterocyclic carbene salts (la-d) and their silver (I) complexes (2a-d) were synthesized. All new compounds were characterized by elemental analysis, FT-IR, H-1 NMR and, C-13 NMR spectroscopy. Additionally, single crystal structural studies for complex 2d show that the benzene rings (C9-C14) and the central benzimidazole ring system make dihedral angles of 83.58(13)degrees. The Ag-Cl and Ag-C single bond lengths are 2.3267(8) and 2.087(3) angstrom, respectively. The C-Ag-Cl bond angle is 175.20(7)degrees. The prop-1-ene moiety attached at the second N-atom of benzimidazole is disordered at two set of sites with an occupancy ratio of 0.592(6): 0.408(6). There is one intramolecular hydrogen bond interaction between C22A-H22A... N2. The salts and Ag-complexes were further evaluated for their in vitro anticancer activities against DU-145 human prostate cancer cells, MCF-7, MDA-MB-231 human breast cancer cells and L-929 non-cancer cell for 24 h, 48 h and 72 h using the MTT assay. The Ag(I)-NHC complexes (2a-d) showed a dose and time-dependent cytotoxic activity against all cell lines. The IC(50)s for all Ag(I) NHC complexes lower than 1 mu M for 72 h time points on cancer cells. The results showed that complex 2d exhibited the highest activity against all cancer cell lines studied. Further, the complexes had relatively higher cytotoxicity to cancer cells than to non-cancer cell lines. (C) 2018 Elsevier B.V. All rights reserved.Öğe Synthesis, characterization and antimicrobial activity of new silver complexes with N-heterocyclic carbene ligands(Elsevier Science Sa, 2010) Ozdemir, Ilknur; Demir, Serpil; Gunal, Selami; Ozdemir, Ismail; Arici, Cengiz; Ulku, DincerSynthesis, structure, and antimicrobial studies of silver complexes of N-heterocyclic carbene (NHC) are reported. All the silver-NHC complexes (1a-f) were prepared from the benzimidazolium salts by the reactions with Ag2O in dichloromethane as a solvent at room temperature. The new compounds characterized by H-1 NMR, C-13 NMR, IR and elemental analysis techniques which support the proposed structures. Chloro[1-(2,4,6-trimethylbenzyl)-3-(methoxyethyl) benzimidazol-2-ylidene] silver(I) complex was structurally characterized by single-crystal X-ray diffraction. A series of new Ag-NHC complexes were screened for their in vitro antimicrobial activity against a variety of Gram-positive and Gram-negative bacteria as well as for their antifungal activity against a Candida albicans and Candida tropicalis. (c) 2010 Elsevier B. V. All rights reserved.Öğe Synthesis, characterization, and application to transfer hydrogenation of ?6-(3,4,5-trimethoxybenzyl)-?1-N-heterocyclic carbene-ruthenium complex(Taylor & Francis Ltd, 2011) Demir, Serpil; Ozdemir, Ismail; Cetinkaya, Bekir; Sahin, Ertan; Arici, CengizA new chelating ruthenium complex was synthesized using an electron-rich olefin and [RuCl2(p-cymene)](2) and characterized structurally and spectroscopically. The structure of the complex was verified using X-ray crystallography. The complex displayed high activities in transfer hydrogenation.
