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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 Preparation and characterization of PEPPSI-palladium N-heterocyclic carbene complexes using benzimidazolium salts catalyzed Suzuki-Miyaura cross coupling reaction and their antitumor and antimicrobial activities(Taylor & Francis Ltd, 2019) Boubakri, Lamia; Dridi, Khaireddine; Al-Ayed, Abdullah Sulaiman; Ozdemir, Ismail; Yasar, Sedat; Hamdi, NaceurNew palladium complexes were efficiently synthesized from the reaction of benzimidazolium salts 2a-e, potassium carbonate (K2CO3) and palladium chloride (PdCl2) in pyridine (for 3a-e). The catalytic activity of these complexes in a catalytic system including palladium complexes and K2CO3 in DMF-H2O was evaluated in Suzuki-Miyaura cross-coupling reactions of aryl bromides and chlorides with phenylboronic acid. Our novel complexes show excellent catalytic activities with high turnover numbers (TON) and high turnover frequencies (TOF) (e.g. for the Suzuki-Miyaura reaction: TON up to 370 and TOF up to 123.3 h(-1)). Both benzimidazolium salts 2a-e and complexes 3 have been characterized using spectroscopic data and elemental analysis. The antimicrobial activity of the N-heterocyclic carbene palladium complexes 3a-e varies with the nature of the ligands. Also, the IC50 values of both, complexes (3a-e) and benzimidazoles 2a-e, have been determined. In addition, the new palladium complexes were screened for their antitumor activity. Complexes 3e and 3d exhibited the highest antitumor effect with IC50 values 6.85 mu g/mL against MCF-7 and 10.75 mu g/mL against T47D, respectively. [GRAPHICS] .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 Ruthenium(II) complexes bearing benzimidazole-based N-heterocyclic carbene (NHC) ligands as potential antimicrobial, antioxidant, enzyme inhibition, and antiproliferative agents(Taylor & Francis Ltd, 2022) Boubakri, Lamia; Chakchouk-Mtiba, Ahlem; Naouali, Olfa; Mellouli, Lotfi; Mansour, Lamjed; Ozdemir, Ismail; Yaser, SedatIn this work, new substituted benzimidazolium salts 2a-d having different groups on the side chain have been synthesized and reacted with Ag2O to produce Ag(I) N-heterocyclic carbene (NHC) complexes 3a-d. Ag(I)-NHC complexes were used as a carben transfer agents to synthesize ruthenium(II)-NHC complexes 4a-d. The structures of all compounds were characterized by H-1 NMR, C-13 NMR and FT-IR spectroscopies and elemental analysis. The IC50 values of these complexes were determined by MTT assay against MCF7, MDA-MB-231 and HF cancer cell lines. The lowest MIC values were obtained for two complexes, 4b and 4d. The Ru(II)-NHC complexes generally triggered stronger bacterial growth inhibition than the metal-free benzimidazolium cations. Enzymatic inhibition investigation against acetylcholinesterase (AChE) and tyrosinase (TyrE) showed that 4b and 4d are the most potent inhibitors against AchE with an IC50 of 2.52 and 5.06 mu g mL(-1), respectively, and against TyrE with an IC50 of 19.88 and 24.95 mu g mL(-1), respectively. Antioxidant activity of the synthesized NHC ligands 2a-2d and their respective Ru(II)-NHC complexes 4a-4d was assessed by three different techniques: the 2.2-diphenyl-1-picrylhydrazyl (DPPH), the 2.2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals scavenging and the beta-carotene linoleic acid bleaching assay, showing that 4d has recorded an important antioxidant activity.Öğe Synthesis of novel Ag(I)-N-heterocyclic carbene complexes soluble in both water and dichloromethane and their antimicrobial studies(Taylor & Francis Ltd, 2019) Boubakri, Lamia; Dridi, Khaireddine; Al-Ayed, Abdullah Sulaiman; Ozdemir, I.; Yasar, S.; Hamdi, NaceurThe interaction of the benzimidazolium salt with Ag2O in dichloromethane to prepare novel Ag(I)-N-heterocyclic carbene complexes has been carried out at room temperature for 48 h in the absence of light. The obtained complexes were identified and characterized by H-1 and C-13 NMR, FT-IR and elemental analysis techniques. In addition, it has been found that some of the complexes are antimicrobially active and show higher activity than the free ligand. Probably metal chelation affects significantly the antimicrobial behavior of the ligands. The minimum inhibitory concentration of the complexes was determined. The results indicated that these complexes exhibit antimicrobial activity.
