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Öğe Antimicrobial activities of bis-(N-alkylbenzimidazole)-cobalt(II) and zinc (II) complexes(2023) Şahin, Neslihan; Üstün, Elvan; Özdemir, İlknur; Günal, Selami; Özdemir, Namık; Bülbül, Hakan; Gürbüz, Nevin; Özdemir, İsmail; Semeril, DavidEight benzimidazole precursors (L), namely 1-allyl-benzimidazole, 1-methallyl-benzimidazole, 1-isopropyl-benzimidazole, 1-(3-methyloxetan-3-yl)methyl-benzimidazole, 1-allyl-5,6-dimethyl-benzimidazole, 1-methallyl-5,6- dimethyl-benzimidazole, 1-isopropyl-5,6-dimethyl-benzimidazole and 1-(3-methyloxetan-3-yl)methyl-5,6- dimethyl-benzimidazole, were coordinated to cobalt(II) and zinc(II) cations to form complexes of the type [MCl2L2]. Single-crystal X-ray structures were determined for two cobalt(II) and for one zinc(II) complexes and confirmed their tetrahedral molecular geometry. The antibacterial and antifungal activities of these two series of cobalt(II) and zinc(II) complexes were studied against Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii and Klebsiella pneumoniae), Gram-positive (Staphylococcus aureus, methicillin-resistant S. aureus and Enterococcus faecalis) bacteria and fungal strains (Candida albicans and Candida glabrata). Overall, cobalt(II) complexes were more effective than the zinc(II) complexes against all microorganisms. The most significant results were obtained with the two dichloro-bis(1-allyl-5,6-dimethylbenzimidazole)-cobalt(II) and dichloro-bis(1-methallyl-5,6-dimethylbenzimidazole)-cobalt(II) complexes against Candida albicans and Candida glabrata fungi with measured minimal inhibitory concentrations as low as 0.024 μmol/mL, values close to those obtained with the commercially available drug Flucanozole (0.020 μmol/mL).Öğe Antimicrobial activity, inhibition of biofilm formation, and molecular docking study of novel Ag-NHC complexes(Elsevier, 15/09/2021) Çelik, Cem; Şahin, Neslihan; Üstün, Elvan; Tutar, Uğur; Gürbüz, Nevin; Özdemir, İsmailIn this study, we reported the synthesis of a new series of Silver(I)-N-heterocyclic carbene complexes which were obtained from the corresponding new N-heterocyclic carbene (NHC) precursors. All new compounds were characterized by elemental analysis, FT-IR, LC-MS, 1 H NMR, and 13 C{ 1 H} NMR spec- troscopy. These new N-heterocyclic carbene precursors and Ag(I)-NHC complexes were evaluated for their antibacterial, antifungal, and antibiofilm activities. The biological activities of synthesized products were compared with standard drugs. All compounds have moderate antibacterial and antibiofilm activities. In particular, while compound 2a was found to be the best inhibitor of E. coli biofilms, while compound 2d inhibited C. albicans biofilm at the highest rate. All the compounds were also analyzed by molecular docking methods with the certain target molecules.Öğe Benzimidazol-2-ylidene Silver Complexes: Synthesis, Characterization, Antimicrobial and Antibiofilm Activities, Molecular Docking and Theoretical Investigations(2023) Tutar, Uğur; Çelik, Cem; Üstün, Elvan; Özdemir, Namık; Şahin, Neslihan; Semeril, David; Gürbüz, Nevin; Özdemir, İsmailFive silver(I) complexes, namely chloro[1-methallyl-3-benzyl)benzimidazol-2-ylidene] silver (6), chloro[1-methallyl-3-(2,3,5,6-tetramethylbenzyl)benzimidazol-2-ylidene]silver (7), chloro[1- methallyl-3-(3,4,5-trimethoxylbenzyl)benzimidazol-2-ylidene]silver (8), chloro[1-methallyl- 3- (naphthylmethyl)benzimidazol-2-ylidene]silver (9), and chloro [1-methallyl-3-(anthracen-9-ylmethyl) benzimidazol-2-ylidene]silver (10), were prepared starting from their corresponding benzimidazolium salts and silver oxide in 71–81% yields. A single-crystal X-ray structure of 7 was determined. These five Ag-NHC complexes were evaluated for their antimicrobial and biofilm formation inhibition properties. Complex 10 exhibited high antimicrobial activities comparable to those obtained with standard drugs such as Fluconazole in contact with Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Acinetobacter baumannii, and Candida albicans. The latter complex has been shown to be very efficient in antibiofilm activity, with 92.9% biofilm inhibition at 1.9 g/mL on Escherichia coli. Additionally, the molecules were optimized with DFT-based computational methods for obtaining insight into the structure/reactivity relations through the relative energies of the frontier orbitals. The optimized molecules were also analyzed by molecular docking method against DNA gyrase of Escherichia coli and CYP51 from Candida albicans.Öğe A benzimidazolium salt as effective corrosion inhibitor against the corrosion of mild steel in acidic medium: experimental and theoretical studies(2022) Şahin, Neslihan; Kaya Savaş; Aydın, Özkan; Katin, Konstantin P.; Chaouiki, Abdelkarim; Gürbüz, Nevin; Özdemir, İsmail; Farsak, MuratA new benzimidazolium salt (1-Allyl-3-(2,3,5,6-tetramethylbenzyl)- 5,6-dimethylbenzimidazoliumchloride) is characterized by using 1H NMR and 13C(1H) NMR spectroscopies. The corrosion inhibition performance of benzimidazolium salt for mild steel in an acidic medium is investigated with the help of both experimental and theoretical tools. The experimental part of inhibition analysis includes the use of electrochemical impedance spectroscopy (EIS), linear sweep voltammetry, potentiodynamic polarization techniques, and surface characterizations are made. In the theoretical part, Density Functional Theory calculations are performed to discuss the corrosion inhibition efficiency using quantum chemical parameters. Molecular Dynamic Simulation calculation is made to analyze adsorption properties and characteristics of synthesized molecules on mild steel. Experimental studies show that the inhibition efficiency is calculated as 97.6% from EIS results for 5 10 3 M inhibitor. Both experimental analyses and theoretical calculations proved that the studied inhibitor molecule is exhibiting higher inhibition efficiency.Öğe Design, synthesis, antimicrobial activity and molecular docking study of cationic bis?benzimidazole?silver(I) complexes(2023) Üstün, Elvan; Şahin, Neslihan; Özdemir, İlknur; Günal, Selami; Gürbüz, Nevin; Özdemir, İsmail; Semeril, DavidTwo series of bis(1‐alkylbenzimidazole)silver(I) nitrate and bis(1‐alkyl‐5,6‐ dimethylbenzimidazole)silver(I) nitrate complexes, in which the alkyl substituent is either an allyl, a 2‐methylallyl, an isopropyl or a 3‐methyloxetan‐3‐yl‐methyl chain, were synthesized and fully characterized. The eight N‐coordinated silver(I) complexes were screened for both antimicrobial activities against Gram‐negative (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii) and Gram‐positive (Staphylococcus aureus, Staphylococcus aureus MRSA, and Enterococcus faecalis) bacteria and antifungal activities against Candida albicans and Candida glabrata strains. Moderate minimal inhibitory concentrations (MIC) of 0.087 μmol/mL were found when the Gram‐negative and Gram‐positive bacteria were treated with the silver complexes. Nevertheless, MIC values of 0.011 μmol/mL, twice lower than for the well‐known fluconazole, against the two fungi were measured. In addition, molecular docking was carried out with the structure of Escherichia coli DNA gyrase and CYP51 from the pathogen Candida glabrata with the eight organometallic complexes, and molecular reactivity descriptors were calculated with the density functional theory‐based calculation methods.Öğe Pd-PEPPSI: X-ray Structure, Spectroscopic Analyses, and Quantum Mechanical Studies(2021) Kılıç-Cıkla, Işın; Şahin, Neslihan; Özdemir, Namık; Gürbüz, Nevin; Özdemir, İsmailPyridine enhanced precatalyst preparation stabilization and initiation (PEPPSI) complexes contain two halides, an unstable pyridine derivative and a bulky N-heterocyclic carbene (NHC) ligand. In this study, a new palladium-PEPPSI complex, dichloro[1-allyl-3-(2,3,5,6-tetramethylbenzyl)benzimidazole-2- ylidene]pyridine palladium(II), was synthesized and fully characterized by elemental analysis, X-ray crystallography, FT-IR, 1H, and 13C NMR spectroscopy techniques. In addition, the molecular geometries, vibrational frequencies, and 1H and 13C NMR chemical shift values of the complex in the ground state have been calculated using the density functional theory (DFT) method with B3LLP/SDD. The frontier molecular orbitals analyses have been performed to explain the energetics and chemical reactivity of palladium-PEPPSI complex. Stability of the complex resulting from hyperconjugative interactions has been analyzed with natural bond orbital (NBO) analysis. The non-linear optical (NLO) properties have also been described calculating the polarizability and first order hyperpolarizability of the compound.Öğe PEPPSI type complexes: Synthesis, x-ray structures, spectral studies, molecular docking and theoretical investigations(2021) Serdaroğlu, Goncagül; Şahin, Neslihan; Üstün, Elvan; Tahir, Muhammad Nawaz; Arıcı, Cengiz; Gürbüz, Nevin; Özdemir, İsmailIn 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 ? p* and p ? p* 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.Öğe Synthesis, antimicrobial activity and molecular docking study of benzyl functionalized benzimidazole silver(I) complexes(2023) Arı, Erkan; Şahin, Neslihan; Üstün, Elvan; Dündar, Muhammed; Karcı, Hüseyin; Özdemir, İlknur; Koç, Ahmet; Gürbüz, Nevin; Özdemir, İsmailIn this study, a series of N-functionalized benzimidazole silver(I) complexes were prepared and characterized by FT-IR, 1H, 13C{1H} NMR spectroscopy, and elemental analysis. Synthesized N-benzylbenzimidazole silver(I) complexes were evaluated for their antimicrobial activities against bacteria Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and the fungal strains Candida albicans and Candida glabrata. The results indicated that N-alkylbenzimidazole silver(I) complexes exhibited good antimicrobial activity compared to N-alkylbenzimidazole derivatives. Especially, complex 2e presented perfect antimicrobial activity than the other complexes. The characterized molecules were optimized by DFT-based calculation methods and the optimized molecules were analyzed in detail by molecular docking methods against bacterial DNA-gyrase and CYP51. The amino acid residues detected for both target molecules are consistent with expectations, and the calculated binding affinities and inhibition constants are promising for further studies.Öğe Synthesis, characterization, antimicrobial and antibiofilm activity, and molecular docking analysis of NHC precursors and their Ag-NHC complexes(2021) Şahin, Neslihan; Üstün, Elvan; Çelik, Cem; Tutar, Uğur; Özdemir, Namık; Gürbüz, Nevin; Özdemir, İsmailMicroorganisms attach to surfaces and interfaces and form biofilms which create a sheltered area for host cell response. Therefore, biofilms provide troubles in fields such as medicine, food, and pharmaceuticals. Inhibition of formation of biofilms through hindering of quorum sensing could be a method for the production of new generation antibiotics. In this study, four new benzimidazole type NHC precursors (1-allyl- 3-benzyl-5,6-dimethylbenzimidazolium chloride, 1-allyl-3-(2,4,6-trimethylbenzyl)-5,6-dimethylbenzimidazolium chloride, 1-allyl-3-(2,3,5,6-tetramethylbenzyl)-5,6-dimethylbenzimidazolium chloride, and 1-allyl-3-(2,3,4,5,6-pentamethylbenzyl)-5,6-dimethylbenzimidazolium chloride and Ag-NHC complexes of these molecules were synthesized and characterized by elemental analysis, FT-IR spectroscopy, 1H, and 13C{1H} NMR spectroscopy, LC-MS, and single crystal crystallography. Antimicrobial and biofilm formation inhibition activities of the molecules were evaluated. In addition, the activities of the molecules were examined in detail by molecular docking analysis. According to the results obtained, higher activity was achieved with the complex molecules when compared with the benzimidazole derivative ligands.Öğe Synthesis, characterization, antimicrobial and antibiofilm activity, and molecular docking analysis of NHC precursors and their Ag-NHC complexes†(The Royal Society of Chemistry, 2 November 2021) Çelik, Cem; Üstün, Elvan; Şahin, Neslihan; Tutar, Uğur; Özdemir, Namık; Gürbüz, Nevin; Özdemir, İsmailMicroorganisms attach to surfaces and interfaces and form biofilms which create a sheltered area for host cell response. Therefore, biofilms provide troubles in fields such as medicine, food, and pharmaceuticals. Inhibition of formation of biofilms through hindering of quorum sensing could be a method for the production of new generation antibiotics. In this study, four new benzimidazole type NHC precursors (1-allyl- 3-benzyl-5,6-dimethylbenzimidazolium chloride, 1-allyl-3-(2,4,6-trimethylbenzyl)-5,6-dimethylbenzimidazolium chloride, 1-allyl-3-(2,3,5,6-tetramethylbenzyl)-5,6-dimethylbenzimidazolium chloride, and 1-allyl-3-(2,3,4,5,6-pentamethylbenzyl)-5,6-dimethylbenzimidazolium chloride and Ag-NHC complexes of these molecules were synthesized and characterized by elemental analysis, FT-IR spectroscopy, 1H, and 13C{1H} NMR spectroscopy, LC-MS, and single crystal crystallography. Antimicrobial and biofilm formation inhibition activities of the molecules were evaluated. In addition, the activities of the molecules were examined in detail by molecular docking analysis. According to the results obtained, higher activity was achieved with the complex molecules when compared with the benzimidazole derivative ligands.Öğe Synthesis, in vitro anticancer activities, and quantum chemical investigations on 1,3-bis-(2-methyl-2-propenyl)benzimidazolium chloride and its Ag(I) complex(2021) Serdaroğlu, Goncagül; Şahin-Bölükbaşı, Serap; Barut-Celepçi, Duygu; Sevinçek, Resul; Şahin, Neslihan; Gürbüz, Nevin; Özdemir, İsmail1,3-Bis-(2-methyl-2-propenyl)benzimidazolium chloride and its Ag(I) complex are synthesized and the structures are elucidated using spectroscopies techniques. The molecular and crystal structures of the benzimidazolium salt are confirmed by X-ray crystallography. The molecular geometries of the benzimidazolium and its Ag(I) salt are analyzed using the B3LYP functional with the 6–311+G(d,p)/LANL2DZ basis set. The observed Fourier transform infrared and nuclear magnetic resonance isotropic shifts are compared with the calculated values. Besides, the quantum chemical identifiers, significant intramolecular interactions, and molecular electrostatic potential plots are used to show the tendency/site of the chemical reactivity behavior. The three-dimensional Hirshfeld surfaces and the associated twodimensional fingerprint plots are applied to obtain an insight into the behavior of the interactions in the crystal. Both compounds are tested for their in vitro anticancer activities against DU-145 and MCF-7 cancer cells and L-929 noncancer cells using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.
