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Öğe Bioactive NHC-derived palladium complexes: synthesis, catalytic activity for the Suzuki-Miyaura coupling of aryl chlorides and bromides and their antibacterial activities(Taylor & Francis Ltd, 2019) Boubakri, Lamia; Al-Ayed, Abdullah S.; Mansour, L.; Abutaha, Nael; Harrath, Abdel Halim; Ozdemir, I; Yasar, S.Pd(II)-bis(NHC) complexes (where NHC = N-heterocyclic carbene) bearing asymmetrically and symmetrically substituted NHC-ligand have been synthesized via deprotonation of 5,6-dimethylbenzimidazolium salts. The NHC precursors have been achieved via the two step N-alkylation of 5,6-dimethylbenzimidazole. The resultant salts were deprotonated with PdCl2 and K2CO3 in dry THF for 2(a-e). The obtained complexes were identified and characterized by H-1 and C-13 NMR, FT-IR, DART-TOF mass spectrometry and elemental analysis. These new Pd(II)-bis(NHC) complexes were applied as catalyst precursors for Suzuki-Miyaura cross-coupling reactions of aryl bromides and chlorides with phenylboronic acid to afford the corresponding products in good yields. This catalytic reaction was evaluated in the presence of KOtBu/toluene. The antibacterial activities of 2(a-e) were investigated against Gram (+)/(-) bacteria using the agar dilution procedure. The antibacterial activities of 2 vary with the nature of the ligands; MIC values of 2(a-e) were determined.Öğe Copper-catalyzed azide-alkyne cycloaddition (CuAAC) under mild condition in water: Synthesis, catalytic application and biological activities(Elsevier Science Sa, 2017) Touj, N.; Chakchouk-Mtibaa, A.; Mansour, L.; Harrath, A. H.; Al-Tamimi, J. H.; Ozdemir, I.; Mellouli, L.A series of Cu-N-heterocyclic carbene (Cu-NHC) complexes, 3a-c, were synthesized and characterized by spectroscopic methods such as NMR, HRMS and elemental analysis. The performance of these (Cu-NHC) complexes, 3a-c showed excellent activity in 1,3-dipolar cycloaddition reactions between alkynes and azides to obtain 1,4-disubstituted triazoles 6a-d in 80%-91% isolated yields. All obtained complexes especially compounds 3a and 3c, presented significant inhibitory activity against the tested food-borne pathogens and clinical microorganisms. The compound 3a presents against S. aureus a MIC value of 4.8 mg/ml quite similar to that of ampicillin (4 mg/ml) used as standard. Compounds 3a and 3b, from a concentration of 0.5 mg/ml, present an identical scavenging activity to that of the two used controls butylated hydroxytoluene (BHT) and gallic acid (GA). Concerning acetylcholinesterase inhibition activity (AChEI), compound 6a presents an interesting AChEI activity with 68.3% of inhibition. (C) 2017 Published by Elsevier B.V.Öğe In situ palladium/N-heterocyclic carbene complex catalyzed carbonylative cross-coupling reactions of arylboronic acids with 2-bromopyridine under CO pressure: efficient synthesis of unsymmetrical arylpyridine ketones and their antimicrobial activities(Springer, 2019) Boubakri, L.; Al-Ayed, Abdullah S.; Mansour, L.; Harrath, A. A.; Al-Tamimi, J.; Ozdemir, I.; Yasar, S.The carbonylative Suzuki cross-coupling of 2-bromopyridine with various boronic acids to prepare unsymmetrical arylpyridine ketones has been carried out using palladium/N-heterocyclic carbene complexes as catalysts prepared in situ. The selectivity and the rate of these reactions are highly dependent on the conditions, i.e., nature of the palladium catalyst precursor, solvent, temperature and CO pressure. The main side-products arise from direct, non-carbonylative cross-coupling. Under the optimum conditions, arylpyridine ketones are recovered in high yields (60-88%). The antibacterial activities of the corresponding benzimidazole salts 2 were tested against Gram positive and negative bacteria using the agar dilution procedure, and their IC50 values have been determined.Öğe N-Heterocyclic carbene-palladium-PEPPSI complexes and their catalytic activity in the direct C-H bond activation of heteroarene derivatives with aryl bromides: synthesis, and antimicrobial and antioxidant activities(Royal Soc Chemistry, 2021) Hamdi, N.; Slimani, I.; Mansour, L.; Alresheedi, Faisal; Gurbuz, N.; Ozdemir, I.In this study, a series of unsymmetrical 1,3-disubstituted benzimidazolium chlorides 2a-g with two nitrogen atoms substituted by different alkyl groups were synthesized in high yields as N-heterocyclic carbene (NHC) precursors. These benzimidazolium salts were then converted into the corresponding Pd-NHC complexes of the PEPPSI family (PEPPSI = pyridine-enhanced precatalyst preparation, stabilization, and initiation) 3a-g. The structures of all compounds were characterized by H-1 nuclear magnetic resonance (NMR) spectroscopy, C-13 NMR spectroscopy, infrared spectroscopy, and elemental analysis, which support the proposed structures. The structure of the 3c complex was determined by X-ray crystallography. More detailed structural characterization of the 3c complex was performed through single-crystal X-ray diffraction, which supports the proposed structures. The Pd-NHC-PEPPSI complexes were used as catalysts in the direct C-5-arylation of 2-acetyl furan, 2-acetylthiophene, and 2n-propylthiazole with different aryl bromides. These complexes exhibited moderate-to-high catalytic activities and selectively at the C-5 position. Furthermore, the Pd-NHC-PEPPSI complexes were evaluated for their potential antibacterial properties against a panel of bacterial strains, such as Micrococcus luteus, Listeria monocytogenes, Salmonella typhimurium, Staphylococcus aureus, Candida albicans, and Pseudomonas aeruginosa. The Pd-NHC-PEPPSI complex 3f showed better activity than ampicillin against Micrococcus luteus, with an MIC of 0.035 mg mL(-1). In addition, the antioxidant activities of the complexes 3d and 3f showed considerable free radical scavenging activity.Öğe N-Heterocyclic carbene-Pd(II)-PPh3 complexes as a new highly efficient catalyst system for the Sonogashira cross-coupling reaction: Synthesis, characterization and biological activities(Taylor & Francis Ltd, 2018) Boubakri, L.; Mansour, L.; Harrath, A. H.; Ozdemir, I.; Yasar, S.; Hamdi, N.A novel series of N-heterocyclic carbene-phosphine palladium(II) complexes has been synthesized and fully characterized by IR, H-1 NMR, C-13 NMR, and P-31 NMR spectroscopies, and elemental analysis. The new N-heterocyclic carbene (NHC)-phosphine palladium(II) complexes 3a-h have been easily prepared by the reaction of the corresponding PEPPSI (pyridine-enhanced precatalyst preparation stabilization and initiation) complexes 2a-h and triphenylphosphine in dichloromethane in high yields. These complexes were applied as catalyst precursors which efficiently catalyzed Sonogashira reactions between aryl bromides and phenylacetylene to afford the corresponding products in good yields. The bulky NHC-Pd-PPh3 complexes 3 were tested against Gram-positive and Gram-negative bacteria to study their biological activity. All the complexes exhibit antibacterial against these organisms. Investigation of the antiacetylcholinesterase activity of the studied complexes showed that compounds 3a and 3b exhibited moderate activity at 100 mu g mL-1 and product 3b is the most active.Öğe Ru(ii)-N-heterocyclic carbene complexes: synthesis, characterization, transfer hydrogenation reactions and biological determination(Royal Soc Chemistry, 2019) Boubakri, Lamia; Chakchouk-Mtibaa, A.; Al-Ayed, Abdullah S.; Mansour, L.; Abutaha, Nael; Harrath, Abdel Halim; Mellouli, L.A series of ruthenium(ii) complexes with N-heterocyclic carbene ligands were successfully synthesized by transmetalation reactions between silver(i) N-heterocyclic carbene complexes and [RuCl2(p-cymene)](2) in dichloromethane under Ar conditions. All new compounds were characterized by spectroscopic and analytical methods. These ruthenium(ii)-NHC complexes were found to be efficient precatalysts for the transfer hydrogenation of ketones by using 2-propanol as the hydrogen source in the presence of KOH as a co-catalyst. The antibacterial activity of ruthenium N-heterocyclic carbene complexes 3a-f was measured by disc diffusion method against Gram positive and Gram-negative bacteria. Compounds 3d exhibited potential antibacterial activity against five bacterial species among the six used as indicator cells. The product 3e inhibits the growth of all the six tested microorganisms. Moreover, the antioxidant activity determination of these complexes 3a-f, using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2 '-azinobis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) as reagent, showed that compounds 3b and 3d possess DPPH and ABTS antiradical activities. From a concentration of 1 mg ml(-1), these two complexes presented a similar scavenging activity to that of the two used controls gallic acid (GA) and butylated hydroxytoluene (BHT). From a concentration of 10 mg ml(-1), the percentage inhibition of complexes 3b and 3d was respectively 70% and 90%. In addition, these two Ru-NHC complexes exhibited antifungal activity against Candida albicans. Investigation of the anti-acetylcholinesterase activity of the studied complexes showed that compounds 3a, 3b, 3d and 3e exhibited good activity at 100 mu g ml(-1) and product 3d is the most active. In a cytotoxicity study the complexes 3 were evaluated against two human cancer cell lines MDA-MB-231 and MCF-7. Both 3d and 3e complexes were found to be active against the tested cell lines showing comparable activity with examples in the literature.Öğe Substituted N-heterocyclic carbene PEPPSI-type palladium complexes with different N-coordinated ligands: Involvement in the direct C-H bond activation of heteroarenes derivatives with aryl bromide and their antimicrobial, anti-inflammatory and antioxidant activities(Elsevier Science Sa, 2022) Slimani, I; Boubakri, L.; Ozdemir, N.; Mansour, L.; Ozdemir, I; Gurbuz, N.; Yasar, S.In this study new benzimidazolium salt as N-heterocyclic carbene precursors and their related new PEPPSI-Pd (II)-N-heterocyclic carbene (NHC) complexes 3a-e were prepared and caracterized. The structures of all compounds have been characterized by H-1 NMR, C-13 NMR, and IR spectroscopy, as well as elemental analysis techniques and Direct analysis in real time (DART)-time-of-flight mass spectrometry (TOF-MS), which support the proposed structures. Further confirmations of structural details were provided by a single-crystal X-ray. A single crystal of PEPPSI-Pd(II)-N-heterocyclic carbene (NHC) complex 3c shows that the coordination geometry around Pd slightly distorted square-planar geometry. Next, the PEPPSI-Pd(II)-N-heterocyclic carbene (NHC) complexes 3a-e were used as catalysts in the direct C-5-arylation of 2-acetyl furan and 2-acetylthiophene with various aryl bromides. These complexes exhibited moderate to high catalytic activities and gave C-H activation selectively at the C-5-position. Further, PEPPSI-Pd(II)-N-heterocyclic carbene (NHC) complexes 3a-e have been evaluated for their potential antibacterial properties against a panel of bacterial strains namely, Micrococcus luteus, Listeria monocytogenes, Salmonella Typhimurium, Staphylococcus aureus, candida albican and pseudomonas aeruginosa. In addition; these new PEPPSI-Pd(II)-N-heterocyclic carbene (NHC) complexes 3a-e were investigated for anti-oxidant activities by super oxide radical; DPPH (2,2-Diphenyl-1-picrylhydrazyl); and hydroxyl radical scavenging assays; in which most of them displayed significant antioxidant activities. Furthermore; PEPPSI-Pd(II)-N-heterocyclic carbene (NHC) complexes 3a-e were evaluated for anti-inflammatory activity by indirect haemolytic and lipoxygenase inhibition assays and revealed good activity.Öğe Synthesis, characterization, biological determination and catalytic evaluation of ruthenium(ii) complexes bearing benzimidazole-based NHC ligands in transfer hydrogenation catalysis(Royal Soc Chemistry, 2020) Slimani, Ichraf; Chakchouk-Mtibaa, A.; Mansour, L.; Mellouli, L.; Ozdemir, I; Gurbuzd, Nevin; Hamdi, NaceurA new series of ruthenium(ii) N-heterocyclic carbene complexes has been synthesized via transmetalation. These complexes are easily handled in very good yields via synthesis of silver-NHC complexes and subsequent reaction with [RuCl2(p-cymene)](2) in dichloromethane (DCM) under argon atmosphere. The new ruthenium(ii)-NHC complexes were applied to transfer hydrogenation of ketone derivatives using 2-propanol as a hydrogen source and KOH as a co-catalyst. The results show that the corresponding alcohols could be obtained in good yield with high catalyst activity (up to 76%) under mild conditions. All new compounds were characterized by spectroscopic and analytical methods. The antibacterial activities of the corresponding ruthenium(ii)-NHC complexes 4a-i were tested against positive and negative bacteria using the agar dilution procedure and their IC50 values have been determined. A cytotoxicity study of the ruthenium(ii)-NHC complexes 4 was performed against the two human cancer cell lines MDA-MB-231 and MCF-7. In addition, the scavenging activity of the synthesized complexes for the DPPH radical was also determined.Öğe Synthesis, spectroscopic properties and biological activity of new Cu(I) N-Heterocyclic carbene complexes(Elsevier, 2019) Touj, N.; Chakchouk-Mtibaa, A.; Mansour, L.; Harrath, A. H.; Al-Tamimi, J.; Mellouli, L.; Ozdemir, INew benzimidazolium salts (2) and their copper N-heterocyclic carbene complexes (3 4) were designed, synthesized and structurally characterized by NMR (H-1 and C-13), IR, HRMS and elemental analysis. All obtained complexes especially compounds 3d and 3e, presented significant inhibitory activity against the tested food-borne pathogens and clinical microorganisms. The compound 3b presents against S. aureus a MIC value of 0.0195 mg/ml quite similar to that of ampicillin (0.0195 mg/ml) used as standard. Compounds 3a and 3b, from a concentration of 0.5 mg/ml, present an identical scavenging activity to that of the two used controls butylated hydroxytoluene (BHT) and gallic acid (GA). Concerning acetylcholinesterase inhibition activity (AChEI), compound 3e presents an interesting AChEI activity with 32.80% of inhibition. (C) 2018 Published by Elsevier B.V.
