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    N-Alkylation and N-Methylation of Amines with Alcohols Catalyzed by Nitrile-Substituted NHC-Ir(III) and NHC-Ru(II) Complexes
    (Amer Chemical Soc, 2023) Cakir, Sinem; Kavukcu, Serdar Batikan; Sahin, Onur; Gunnaz, Salih; Turkmen, Hayati
    A series of nitrile-modified N-heterocyclic carbene (NHC) complexes of Ir(III) (2a-e) and Ru(II) (3a-d) have been prepared by transmetallation of [IrCp*Cl2]2 and [RuCl2(p-cymene)]2 forming an in situ NHC-Ag complex. The structures of all complexes were characterized by 1H NMR, 13C NMR, and Fourier transform infrared (FT-IR) spectroscopies. And the structures were clearly elucidated by performing X-ray diffraction studies on 2b, 3a, and 3c single crystals. The complexes of NHC- Ir(III) (2a-e) and NHC-Ru(II) (3a-d) were investigated in the N-alkylation reaction of aniline derivatives with benzyl alcohols to form N-benzyl amines and in the N-methylation reaction of aniline derivatives with methanol. Both reactions were performed in solvent-free media. The Ir(III) complexes (2a-e) were found to perform essentially better than similar Ru(II) complexes (3a-d) in the N-alkylation and N-methylation reactions. Among the Ir(III) complexes (2a-e), the best results were obtained with 2b. The catalytic mechanisms of both reactions were revealed by 1H NMR study. Formation of Ir-hydride species was observed for both reactions. This new report provides useful information to evaluate the activity of complexes and the differences in sensitivity between the NHCs.
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    Novel Benzimidazole- Platinum(II) Complexes: Synthesis, Characterization, Antimicrobial and Anticancer Activity
    (Elsevier, 2021) Dogan, Umut; Ozcan, Ozge; Alaca, Gizem; Ari, Aydan; Gunnaz, Salih; Yalcin, H. Tansel; Sahin, Onur
    Three new Platinum complexes (1-3) with 2,6-di-tert-butyl-4-(1-phenyl-1H-benzimidazol-2-yl) phenol (L-1), N, N-dimethyl-4-(1-phenyl-1H-benzimidazol-2-yl) aniline (L-2) and 4-(1H-benzimidazol-2-yl)-N, N-dimethylaniline (L-3) were prepared and characterized by FT-IR, NMR and Elemental analyses. The crystal structures of L-1, 1 and geometrical isomer of 1 (1a) were determined by X-Ray crystallography. The cytotoxic activities of the compounds were tested on against SHSY-5Y and U-87 cell lines. The antimicrobial evaluations of the compounds showed that they have a moderate antimicrobial effect on gram positive and gram negative bacteria. (C) 2020 Elsevier B.V. All rights reserved.
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    Novel Schiff base-Pt(ii) complexes: inhibition of Aβ aggregation via histidine interaction
    (Royal Soc Chemistry, 2026) Irisli, Sevil; Dogan, Umut; Gunnaz, Salih; Yurt, Fatma; Sahin, Onur
    In this study, three Schiff base ligands (L1-L3) and their novel platinum(ii) complexes (I-III) were synthesized and characterized using FT-IR, NMR, and elemental analysis. The crystal structure of complex I was determined by X-ray crystallography, while the lipophilicity of the complexes was evaluated by UV-Vis spectroscopy. The ability of the compounds to inhibit A beta aggregation was assessed using the SH-SY5Y human neuroblastoma cell line. Due to its high cytotoxicity, comparable to that of cisplatin, complex II was excluded from further biological investigations. The kinetics of A beta aggregation inhibition were examined fluorometrically using Thioflavin-T, and the binding interactions of the complexes with the A beta 1-42 sequence were elucidated through studies of their interactions with l-histidine using 1H-NMR and LC/QTOF/MS analyses. The results demonstrate that complexes I and III significantly suppress A beta fibril formation, with IC50 values of 50 mu M and 25 mu M, respectively. The enhanced biological activity is attributed to the strong electron-donating properties of the ligand substituents. Overall, these findings reveal that the synthesized complexes effectively inhibit A beta amyloid aggregation and promote cell viability.
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    Piano-stool Ru (II) arene complexes that contain ethylenediamine and application in alpha-alkylation reaction of ketones with alcohols
    (Wiley, 2019) Kavukcu, Serdar Batikan; Gunnaz, Salih; Sahin, Onur; Turkmen, Hayati
    A series of piano-stool Ru (II) complexes (Ru1-7) bearing ethylenediamine with aryl and aliphatic groups were prepared and fully characterized by H-1, C-13, F-19 and P-31 NMR spectroscopy, FT-IR and elemental analysis. The crystal structures of Ru2-4 and Ru-7 were determined by X-ray crystallography. They were successfully applied to the alpha(alpha)-alkylation of aliphatic and aromatic ketones with alcohols via the borrowing hydrogen strategy in mild reaction conditions within a short time. The catalytic system has a broad substrate scope, which allows the synthesis of alpha alkylated ketones with excellent yields. The electronic and steric effects of complexes on catalytic activity were analysed. The influence of the carbon chain length of the ligand on the alpha-alkylation reaction of ketones was also investigated. The catalytic cycle was also examined by H-1-NMR spectroscopy in d(8)-toluene.
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    The Amyloid Beta Aggregation Inhibition Properties of New Pt (II) Complexes and Their Potential in Alzheimer's Treatment
    (Wiley, 2025) Gunnaz, Salih; Sahin, Onur; Irisli, Sevil
    In this study, N-phenylortho-phenylenediamine and N-phenyl ethylenediamine were utilized as amines, and two novel ligands, benzimidazole (LI) and Schiff base (LII), were synthesized through condensation reactions with 3-methoxy-4-benzyloxybenzaldehyde. Furthermore, using these same amines, LIII (benzimidazole) with 3-phenoxybenzaldehyde and LIV (Schiff base) with 4-benzyloxybenzaldehyde were synthesized in accordance with the literature. Then, Pt (II) complexes (Ia, Ib, II, III, and IV) were prepared with these ligands, and it was determined that Ia and Ib are geometric isomers. The ligands and complexes were characterized using 1H-NMR, 13C-NMR, FT-IR, and elemental analysis methods. The cytotoxic effects of these complexes were evaluated on SH-SY5Y neuronal cells. Low-toxicity complexes Ia, II, and IV were then tested for their ability to inhibit amyloid beta (A beta 1-42) aggregation. Thioflavin T fluorescence analysis, AFM imaging, and MALDI-TOF mass spectrometry demonstrated that these complexes, particularly at a 1:1 complex-to-amyloid molar ratio, effectively inhibited A beta aggregation. These findings suggest that Pt (II) complexes containing Schiff base and benzimidazole ligands may be effective against Alzheimer's disease by alleviating A beta toxicity.
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    The imidazo{[4,5-f][1,10]-phenanthrolin}l-2-ylidene and its palladium complexes: Synthesis, characterization, and application in C-C cross-coupling reactions
    (Elsevier Science Sa, 2017) Gok, Lutfiye; Gunnaz, Salih; Sahin, Zarife Sibel; Pelit, Levent; Turkmen, Hayati
    1,3-dibutyl-1H-imidazo[4,5-f][1,10]phenanthrolinium iodide, L-5 center dot 2HI ligand and their mono-, di-, tri-, tetra-nuclear palladium(II) complexes (5 center dot HPF6, 6-8) were synthesized and characterized by elemental analysis, FTIR, UV-visible and NMR spectroscopy. In addition, the complexes (5 center dot HPF6, 6-8) were determined by mass spectrometry (MALDI). The ligand L-5 center dot 2HI was determined by X-ray diffraction. The complexes (5 center dot HPF6, 6-8) were tested in Suzuki-Miyaura and Mizoroki-Heck reactions at elevated temperatures. The activities of the catalysts were monitored by NMR and GC analysis. We found that the poly-nuclear complexes display better activities compared to the mono-nuclear derivatives, thus proposing that an increase in metal moieties which leads to an increase in activity in cross-coupling reaction. (C) 2016 Elsevier B.V. All rights reserved.