Search

Palladium-based complexes with the ligand N-heterocyclic carbene have long received attention as active catalysts for many catalytic reactions. Recently, the biological activities of these air- and moisture-stable complexes have also been investigated. In our work, bis(benzimidazol-2-ylidene)palladium complexes 3a–d were synthesized by reacting benzimidazolium salts 2a–d with PdCl2 under reflux in tetrahydrofuran for 24 h and analyzed by spectroscopy (FT-IR [Fourier transform infrared], 1H NMR [proton nuclear magnetic resonance]) characterization, 13C NMR [carbon-13 (C13) nuclear magnetic resonance]), and elemental analysis. The in vitro antibacterial and antifungal activities of these complexes were studied against Gram-positive and Gram-negative microorganisms, and two different fungi showed their remarkable biological potential. In addition, the analysis of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals using spectrophotometry showed that they are an antioxidant. The potent antibacterial and antioxidant activities of the synthetic complexes suggest that they are more effective antibacterial agents. Our study extends the biological relevance of palladium bis(benzimidazol-2-ylidene) complexes with antibacterial and antioxidant activities. Furthermore, the main goal of the docking simulation is to provide a detailed analysis of the interaction between the complex and the protein of interest.

A series of ruthenium(ii) complexes with N-heterocyclic carbene (NHC) ligands of the general type (arene)(NHC)Ru(ii)X2 (where X = halide) (3a–3d) were synthesized and characterized in order to compare their antibacterial activities with benzimidazolium salts 2. Our comparison revealed that ruthenium(ii) NHC complexes 3 were more active than benzimidazolium salts 2. Furthermore, the two complexes 3b and 3d had a potent inhibitory effect against acetylcholinesterase with an IC50 of 4.52 and 4.04 g·mL−1 and against tyrosinase with an IC50 of 20.77 and 25.84 g·mL−1, respectively. In addition, screening of benzimidazolium salts (2a–2d) and their ruthenium(ii) complexes (3a–3d) against colon carcinoma cell lines (HCT-116) and hepatocellular carcinoma cell lines (HepG-2) were studied. The obtained results revealed that complex 3a is the most active against vinblastines.

Background and Objectives: Colorectal cancer (CRC) remains a major global health issue. Although chemotherapy is the first-line treatment, its effectiveness is limited due to drug resistance developed in CRC. To overcome resistance and improve the prognosis of CRC patients, investigating new therapeutic approaches is necessary. Materials and Methods: Using human colorectal adenocarcinoma (HT29) and metastatic CRC (SW620) cell lines, the potential anticancer properties of a newly synthesized compound 1-(Isobutyl)-3-(4-methylbenzyl) benzimidazolium chloride (IMBZC) were evaluated by performing MTT cytotoxicity, cell migration, and colony formation assays, as well as by monitoring apoptosis-related protein and gene expression using Western blot and reverse transcription–quantitative polymerase chain reaction technologies. Results: Tested at various concentrations, the half-maximal inhibitory concentrations (IC50) of IMBZC on HT29 and SW620 cell growth were determined to be 22.13 µM (6.97 μg/mL) and 15.53 µM (4.89 μg/mL), respectively. IMBZC did not alter the cell growth of normal HEK293 cell lines. In addition, IMBZC inhibited cell migration and significantly decreased colony formation, suggesting its promising role in suppressing cancer metastasis. Mechanistic analyses revealed that IMBZC treatment increased the expression of pro-apoptotic proteins p53 and Bax, while decreasing the expression of anti-apoptotic proteins Bcl-2 and Bcl-xL, thus indicating the induction of apoptosis in IMBZC-treated CRC cells, compared to untreated cells. Additionally, the addition of IMBZC to conventional chemotherapeutic drugs (i.e., 5-fluorouracil, irinotecan, and oxaliplatin) resulted in an increase in the cytotoxic potential of the drugs. Conclusions: This study suggests that IMBZC has substantial anticancer effects against CRC cells through its ability to induce apoptosis, inhibit cancer cell migration and colony formation, and enhance the cytotoxic effects of conventional chemotherapeutic drugs. These findings indicate that IMBZC could be a promising chemotherapeutic drug for the treatment of CRC. Further research should be conducted using in vivo models to confirm the anti-CRC activities of IMBZC. [ABSTRACT FROM AUTHOR]

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 μM mL−1, respectively. These results demonstrate that these compounds are promising candidates for the treatment of colorectal cancer and leishmaniasis. [ABSTRACT FROM AUTHOR]

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 1HNMR, 13C 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 C5 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 °C for 2 hours. In addition, the conversions for substrates containing electron-withdrawing groups were higher than those for substituents containing electron-donating groups. [ABSTRACT FROM AUTHOR]