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Öğe 2-Hydroxyethyl substituted NHC precursors: Synthesis, characterization, crystal structure and carbonic anhydrase, ?-glycosidase, butyrylcholinesterase, and acetylcholinesterase inhibitory properties(Elsevier Science Bv, 2018) Erdemir, Fatos; Celepci, Duygu Barut; Aktas, Aydin; Taslimi, Parham; Gok, Yetkin; Karabiyik, Hasan; Gulcin, IlhamiThis study contains novel a serie synthesis of N-heterocyclic carbene (NHC) precursors that 2-hydroxyethyl substituted. The NHC precursors have been prepared from 1-(2-hydroxyethyl)benzimidazole and alkyl halides. The novel NHC precursors have been characterized by using H-1 NMR, C-13 NMR, FTIR spectroscopy and elemental analysis techniques. Molecular and crystal structures of 2a, 2d, 2e, 2f and 2g were obtained with single-crystal X-ray diffraction studies. These novel NHC precursor's derivatives effectively inhibited the a-glycosidase, cytosolic carbonic anhydrase I and II isoforms (hCA I and II), butyrylcholinesterase (BChE) and acetylcholinesterase (AChE). Inhibition constant (K-i) were found in the range of 0.30-9.22 nM for alpha-glycosidase, 13.90-41.46 nM for hCA I, 12.82-49.95 nM for hCA II, 145.82-882.01 nM for BChE, and 280.92-1370.01 nM for AChE, respectively. (C) 2017 Elsevier B.V. All rights reserved.Öğe Arylation of heterocyclic compounds by benzimidazole-based N-heterocyclic carbene-palladium(II) complexes(Elsevier Science Sa, 2020) Sahin, Neslihan; Gurbuz, Nevin; Karabiyik, Hande; Karabiyik, Hasan; Ozdemir, IsmailSpecific C-H bond can be activated for arylation using aryl halide without the aid of directing the group in the case of electron-rich heteroarenes. The ability to readily generate halo substituted arylated heteroarenes is important in organic chemistry since these species are important building blocks for biochemists. In this manuscript, we report the synthesis of PEPPSI type-novel benzimidazole-based N-heterocyclic carbene-palladium(II) complexes (2a-e). All of the new compounds were fully characterized by H-1, C-13{H-1} NMR and FT-IR spectra. The structures of 2c, 2d, and 2e were determined by X-ray crystallography and the prepared complexes (2a-e) were investigated as catalysts for the direct arylation of 2-n-propylthiazole, 4,5-dimethylthiazole and 2-acetylthiophene with various aryl bromides. High catalytic activity for arylation was seen reaction using only 0.5 mol% catalyst for 1 h. (C) 2019 Elsevier B.V. All rights reserved.Öğe Crystal structure, optical properties, spectroscopic characterization and density functional theory studies of a new rhodium (i)-imidazolidin-2-ylidene complexes: Synthesis, characterization and cytotoxic properties(Elsevier Science Sa, 2022) Karaca, Emine Ozge; Ciftci, Osman; Ozdemir, Ilknur; Karabiyik, Hande; Karabiyik, Hasan; Gurbuz, Nevin; Ozdemir, IsmailRhodium(I) complexes bearing imidazolidin-2-ylidene ligands have been widely used in catalytic chemistry, but there are very few reports of the biological properties of these type complexes. A series of [RhCl(COD)(NHC)] complexes were synthesized. The structures of all compounds were characterized by 1H NMR, 13C NMR, IR and elemental analysis techniques, which supported the proposed structures. The single-crystal structures of complexes 1a and 1c have been determined. Single-crystal X-ray diffraction analysis indicates that complexes 1a and 1c crystallize in the centrosymmetric space groups P n m a and I 1 2/a 1 of the orthorhombic and monoclinic systems respectively. The ground state geometry of these complexes was optimized using density functional theory (DFT) at mixed double zeta basis set, 6-31G(d) for H, C, N, O and Cl and LANL2DZ for Rh. The presence of the different functional groups and the nature of their vibrations were identified by the experimental and theoretical infrared spectra. The optical properties of the studied complex were determined experimentally using UV-visible and photoluminescence techniques in solid-state and theoretically using the TD-DFT method. Hirshfeld surface analysis employing 3D molecular surface contours and 2D fingerprint plots has been used to analyze intermolecular interactions present in the solid-state. The cytotoxic properties of the rhodium(I)-NHC complexes have been assessed in various human cancer lines, including cisplatin-sensitive and resistant cells. IC50 values of these four complexes were determined by the MTS-based assay on three human cancer cell lines; brain (SH-SY5Y), colon (HTC116), and liver (Hep 3B). Substances 1a-d showed 100% anticarcinogenic effect in cancer cell lines at 50 and 100 mu M.Öğe Enhanced ?-back-donation resulting in the trans labilization of a pyridine ligand in an N-heterocyclic carbene (NHC) PdII precatalyst: a case study(Int Union Crystallography, 2019) Karabiyik, Hande; Yigit, Beyhan; Yigit, Murat; Ozdemir, Ismail; Karabiyik, HasanThe molecular structure of the benzimidazol-2-ylidene-PdCl2-pyridine-type PEPPSI (pyridine-enhanced precatalyst, preparation, stabilization and initiation) complex {1,3-bis[2-(diisopropylamino) ethyl] benzimidazol-2-ylidene-kappa C-2}dichlorido(pyridine-kappa N) palladium(II), [PdCl2(C5H5N)(C23H40N4)], has been characterized by elemental analysis, IR and NMR spectroscopy, and natural bond orbital (NBO) and charge decomposition analysis (CDA). Cambridge Structural Database (CSD) searches were used to understand the structural characteristics of the PEPPSI complexes in comparison with the usual Nheterocyclic carbene (NHC) complexes. The presence of weak C-H center dot center dot center dot Cl-type hydrogen-bond and pi-pi stacking interactions between benzene rings were verified using NCI plots and Hirshfeld surface analysis. The preferred method in the CDA of PEPPSI complexes is to separate their geometries into only two fragments, i. e. the bulky NHC ligand and the remaining fragment. In this study, the geometry of the PEPPSI complex is separated into five fragments, namely benzimidazol-2-ylidene (Bimy), two chlorides, pyridine (Py) and the Pd II ion. Thus, the individual roles of the Pd atom and the Py ligand in the donation and back-donation mechanisms have been clearly revealed. The NHC ligand in the PEPPSI complex in this study acts as a strong pi-donor with a considerable amount of pi-back-donation from Pd to Ccarbene. The electron-poor character of Pd II is supported by pi-back-donation from the Pd centre and the weakness of the Pd-N(Py) bond. According to CSD searches, Bimy ligands in PEPPSI complexes have a stronger pi-donating ability than imidazol-2-ylidene ligands in PEPPSI complexes.Öğe Pd-NHC complex catalyzed C-H bond activation reactions of caffeine and 2-isobuthylthiazole(Elsevier, 2022) Bugday, Nesrin; Khan, Siraj; Yasar, Sedat; Bulut, Fatih; Boulebd, Houssem; Karabiyik, Hande; Karabiyik, HasanA series of new Pd-NHC complexes were synthesized, characterized, and utilized as catalysts on 8-(hetero)ary-lation of xanthines and C-5 (hetero)arylation of 2-isobuthylthiazole. All the synthesized derivatives were characterized by NMR, Q-TOF-LC/MS, FTIR, and X-ray (for 4a, 5a, and 5b) analysis. In addition, DFT calculations and computational NBO studies for Pd-NHC complexes were examined, and HOMO and LUMO energy levels and electron density of each Pd-NHC complex were defined. 4a-c and 5a-b complexes showed good catalytic activity in C-H bond activation reactions. DFT studies have also been conducted to examine the reaction mechanism following the CMD pathway. Complex 5a was chosen as a representative catalyst for the reaction of unsubstituted phenyl with caffeine and 2-isobuthylthiazole. Although the delta E values of the complexes are so close, slight difference in the catalytic activity were observed for 4a-c and 5a-b. Since this low delta E value facilitates the oxidative addition reaction of (hetero)aryl bromides, thanks to this catalytic system, new 8-(hetero)aryl xan-thines and 5-(hetero)aryl thiazole derivatives could be synthesized with high yields and low catalyst loading.Öğe Synthesis, characterization and antimicrobial properties of silver complexes derived from 5,6-Dimethylbenzimidazol-2-ylidene(Pergamon-Elsevier Science Ltd, 2023) Cetinkaya, Erdem Atalay; Koc, Ahmet; Koc, Hatice Kubra; Karabiyik, Hande; Karabiyik, Hasan; Ustun, Elvan; Ozdemir, IsmailBenzimidazoles are considered as a class of bioactive heterocyclic compounds that exhibit many biological ac-tivities such as antimicrobial. Benzimidazole-silver complexes also have strong antimicrobial activity, sometimes even higher than that of conventionally used silver antimicrobials. In this study, six new 5,6-dimethylbenzimi-dazolium ligand precursors which were functionalized by using 2-naphthylmethyl and their silver complexes were synthesized. All molecules were characterized by elemental analysis, 1H NMR, 13C NMR, and IR spec-troscopy techniques. Additionally, mu-Dichloro-bis{[1-(2-naphthylmethyl)-3-(benzyl)-5,6-dimethylbenzimidazol-2-ylidene]silver(I)} was characterized structurally in the solid state by X-ray crystallography which was found to be dimeric with two bridging chlorides. In vitro antimicrobial activity of the synthesized compounds investigated in this work was tested against the reference strains: Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 29213) and Pseudomonas aeruginosa (ATCC 27853), Candida albicans (ATCC MYA-2876) and Candida glabrata (ATCC 2001). Some of these new compounds have been found to display significant effectiveness. Also, the molecular docking analysis was performed for all optimized ligands and complexes against SarA
