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    Anticancer, antimicrobial and antiparasitical activities of copper(I) complexes based on N-heterocyclic carbene (NHC) ligands bearing aryl substituents
    (Taylor & Francis Ltd, 2020) Touj, Nedra; Al Nasr, Ibrahim S.; Koko, Waleed S.; Khan, Tariq A.; Ozdemir, Ismail; Yasar, Sedat; Mansour, Lamjed
    New benzimidazolium salts were synthesized as N-heterocyclic carbene precursors. These NHC precursors were metallated with Cu2O and CuI in acetone and water under reflux to give novel copper(I) complexes. The structures of these benzimidazolium salts and copper(I) complexes were characterized on the basis of elemental analysis, H-1 NMR, C-13 NMR, IR and LC-MS spectroscopic techniques. The (NHC)Cu(I) complexes 3-4 were tested against MCF7 and MDA-MB-231 cancer cells, Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA) and Candida albicans microorganisms, Leishmania major promastigotes and amastigotes, Toxoplasma gondii parasites and against Vero cell line in vitro. The synthesized copper NHC carbene complex 4b (1,3-bis(2,3,4,5,6-pentamdthylbenzyl)-2,3-dihydro-1H-benzo[d]imidazol-2-yl)copper(I) chloride) was the most active against MCF7 cancer cells (half growth Inhibition Concentrations (IC50) = 0.3 mu g mL(-1)), as well as the most potent antimicrobial against E. coli (inhibition zone (IZ) = 23.3 mm), MRSA (IZ = 25.5 mm) and C. albicans (IZ = 28.5 mm) besides its antileishmanial activities against L. major promastigotes and amastigotes (IC50 < 0.04 mu g mL(-1)). Compound 4c (1,3-bis(4-(tert-butyl)benzyl)-2,3-dihydro-1H-benzo[d]imida-zol-2-yl)copper(II) bromide) is the most potent anticancer against MDA-MB-231 cancer cells IC50 = 0.4 mu g mL(-1)). Compound 4e (5,6-dimethyl-1,3-bis(2,4,6-trimethylbenzyl)-2,3-dihydro-1H-benzo[d]imidazol-2-yl)copper(I) chloride) is the best suitable antitoxoplasmal drug candidate due to its SI of 16.5. These candidates need further study to identify mode of action and drug standardization.
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    Bridged NHC-Pd(II) complexes: Synthesis, DFT calculations, molecular docking, and investigation of catalytic and biological activities
    (Elsevier Science Sa, 2024) Firat, Tuba; Bugday, Nesrin; Yasar, Seyma; Boulebd, Houssem; Mansour, Lamjed; Koko, Waleed S.; Hamdi, Naceur
    Six palladium(II) ( 3a -f ) complexes of the type [Pd 2 ( mu-Cl) 2 (NHC)] were prepared by transmetallation of the corresponding Ag-NHC and [PdCl 2 (CH 3 CN) 2 ] complexes, and their structures were successfully characterised by 1 H NMR, 13 C NMR, HRMS, FTIR and elemental analysis. Density functional theory (DFT) calculations were also realised for the complexes. The prepared complexes were assessed for their catalytic activity in the C -H arylation of 2-isobuthylthiazole as well as for their biological activities. As results, these complexes were found to be potent catalysts in the creation of C5-arylated 2-isobuthylthiazole derivatives via C -H bond activation reaction. Furthermore, biological activity analysis revealed that complex 3a exhibits high cytotoxicity towards both human colon carcinoma cell lines (HCT-116) and hepatocellular carcinoma cell lines (HepG-2) with IC 50 values of 4.2 and 9.3 mu MmL -1 , respectively. Complex 3b also showed antioxidant activity comparable to that of BHT through DPPH and ABTS assays. Both complexes 3d and 3f also showed significant inhibitory activity towards the AChE enzyme with IC 50 values of 5.06 and 2.52 mu MmL -1 , respectively. Finally, all complexes showed excellent antiparasitic activity, with 3b exhibiting strong antileishmanial activity against both L. major promastigotes and amastigotes. The interaction between the most cytotoxic complexes and DNA, envisaged as a potential mechanism of toxicity, was explored by means of docking studies. In summary, these prepared complexes have the potential to serve as potent catalysts for the synthesis of arylated 2-isobutylthiazole and biologically active agents, paving the way for numerous prospects in the fields of medicinal chemistry and organic synthesis.
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    Palladium(ii)/N-heterocyclic carbene (NHC) catalyzed direct C-H arylation of heteroarenes with different aryl bromides and chlorides
    (Royal Soc Chemistry, 2023) Bensalah, Donia; Mansour, Lamjed; Sauthier, Mathieu; Gurbuz, Nevin; Ozdemir, Ismail; Koko, Waleed S.; Gatri, Rafik
    The growing interest of industry in the field of bi(hetero)arene compounds motivated us to synthesize these compounds via a homogeneous catalytic route using Pd PEPPSI-type complexes through direct arylation. In this study, new Pd PEPPSI-type complexes bearing NHC spectator ligands were synthesized and characterized using spectroscopic techniques, such as (HNMR)-H-1, C-13 NMR, MS spectrometry, FTIR spectroscopy and elemental analysis (PEPPSI = pyridine enhanced precatalyst preparation stabilization and initiation). All the synthesized Pd(II) complexes were stable. The catalytic properties of these complexes were evaluated in the direct C-5 mono-arylation of furan, 2-acetylthiophene and N-methylpyrrole-2-carboxaldehyde derivatives with a wide variety of (hetero)aryl halides. This environmentally attractive procedure was found to be tolerant of a wide variety of functional groups on the aryl halides and good yields were obtained in the presence of 1 mol% catalyst loading at 150 degrees C for 2 hours. In addition, the conversions for substrates containing electron-withdrawing groups were higher than those for substituents containing electron-donating groups.
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    Synthesis, DFT calculations, and investigation of catalytic and biological activities of back-bond functionalized re-NHC-Cu complexes
    (Wiley, 2024) Yagmurlu, Ayse; Bugday, Nesrin; Yasar, Seyma; Boulebd, Houssem; Mansour, Lamjed; Koko, Waleed S.; Hamdi, Naceur
    Five copper complexes (3a-e) stabilized by ring-expanded back-bond functionalized N-heterocyclic carbene ligands (re-NHCs) were produced in the glovebox by reacting free re-NHC with CuI precursor. The potential of these re-NHC-Cu complexes as catalysts on the synthesis of mono- and di-(1,4-disubstituted-1,2,3-triazoles) by Cu-catalyzed azide-alkyne cycloaddition (CuAAC) reactions was investigated. Various spectroscopic approaches were utilized to completely characterize the structures of the re-Cu-NHC complexes. Furthermore, density functional theory (DFT) calculations were carried out to get further insights into their molecular geometry and CuAAC reaction mechanism. The re-NHC-Cu complexes showed high activity on the CuAAC reaction in an open-air atmosphere at rt. The Gibbs free energies as well as the optimized geometries of the intermediates and the transition states of the determining step of the reactions catalyzed by 3a, 3e, and 3b complexes were computed. Complex 3e was found to be the most efficient catalyst among these re-NHC-Cu complexes. Additionally, re-Cu-NHC complexes were investigated for their biological activities, including antiproliferative, antioxidant, AChE and TyrE inhibition, and antiparasitic activity. The results showed that the 3b, 3d, and 3e complexes possessed strong antiproliferative activity against human colon carcinoma (HCT-116) and moderate cytotoxic activity against hepatocellular carcinoma (HepG-2) cell lines. In addition, effective selective antileishmanial effects were observed for the 3e compound against both promastigotes and amastigotes stages of L. major with an IC50 value of 0.027 and 0.39 mu M mL-1, respectively. These results demonstrate that these compounds are promising candidates for the treatment of colorectal cancer and leishmaniasis. re-NHC-Cu complexes have been synthesized and used as catalyst on CuAAC reactions. image