Silver(I), palladium(II) and mercury(II) NHC complexes based on bis-benzimidazole salts with mesitylene linker: Synthesis, structural studies and catalytic activity

Novel Ag(I)-NHC complex: synthesis, in vitro cytotoxic activity, molecular docking, and quantum chemical studies

The importance of organometallic complexes in cancer biology has attracted attention in recent years. In this paper, we look for the in vitro cytotoxic capability of novel benzimidazole-based N-heterocyclic carbene (NHC) precursor (1) and its Ag(I)-NHC complex (2). For this purpose, these novel Ag(I)-NHC complex (2) was characterized by spectroscopic techniques (¹H, ¹³C{¹H} nuclear magnetic resonance (NMR), and Fourier-transform infrared spectroscopy (FT-IR)). Then, in vitro cytotoxic activities of NHC precursor (1) and Ag(I)-NHC complex (2) were investigated against MCF-7, MDA-MB-231 human breast, DU-145 prostate cancer cells, and L-929 healthy cells using MTT assay for 24, 48, and 72 h incubation times. Ag(I)-NHC complex (2) showed promising in vitro cytotoxic activity against all cell lines for three incubation times, with IC₅₀ values lower than 5 µM. It was also determined that (NHC) precursor (1) were lower in vitro cytotoxic activity than Ag(I)-NHC complex (2) against all cell lines. Selectivity indexes (SI_s) of Ag(I)-NHC complex (2) against cancer cells were found higher than 2 for 24 and 48 h incubation time. Besides, the electronic structure and spectroscopic data of the newly synthesized precursor and its Ag-complex have been supported by density functional theory (DFT) calculations and molecular docking analysis. After, the anticancer activity of these compounds has been discussed considering the results of the frontier molecular orbital analysis. We hope that the obtained results from the experiments and computational tools will bring a new perspective to cancer research in terms of supported by quantum chemical calculations.

The crystal structure of 1,1′-(9-ethyl-9H-carbazole-3,6-diyl)bis(3-ethyl-1H-imidazol-3-ium) bis(hexafluorophosphate(IV)), C24H27N5F12P2

C24H27N5F12P2, monoclinic, P21/n (no. 14), a = 12.395(4) Å, b = 16.630(6) Å, c = 26.899(10) Å, β = 90.395(7)°, V = 5545(4) Å3, Z = 8, Rgt(F) = 0.0650, wRref(F2) = 0.1651, T = 113(2) K.

The crystal structure of 3-benzyl-1-((8-(benzyloxy)quinolin-2-yl)methyl)-1H-imidazol-3-ium hexafluorophosphate, C27H24N3OF6P

C27H24N3OF6P, monoclinic, Cc (no. 9), a = 18.0589(18) Å, b = 12.5100(9) Å, c = 13.3659(12) Å, β = 124.522(7)°, V = 2487.9(4) Å3, Z = 4, R gt(F) = 0.0437, wR ref(F 2) = 0.1141, T = 113(2) K.

NHC Pd(II) and Ag(I) Complexes: Synthesis, Structure, and Catalytic Activity in Three Types of C-C Coupling Reactions

Four bis-benzimidazolium salts, 1,4-bis[1'-(N-R-benzimidazoliumyl)methyl]-2,3,5,6-tetramethylbenzene 2X- (L 1 H 2 ·(PF 6 ) 2 : R = ethyl, X = PF6; L 2 H 2 ·Br 2 : R = picolyl, X = Br; L 3 H 2 ·Br 2 : R = benzyl, X = Br; and L 4 H 2 ·Br 2 : R = allyl, X = Br), and their three N-heterocyclic carbene (NHC) Pd(II) and Ag(I) complexes, L 1 Pd 2 Cl 4 (1), L 2 Ag 2 Br 2 (2), and L 4 (AgBr) 2 (3), as well as one anionic complex L 3 H 2 ·(Ag 4 Br 8 ) 0.5 (4), have been synthesized and characterized. Complex 1 adopts a funnel-like type of structure, complex 2 adopts a cyclic structure, and complex 3 is an open structure. In the crystal packing of 1-4, one-dimensional polymeric chains and two-dimensional supramolecular layers are formed via intermolecular weak interactions, including hydrogen bonds, π-π interactions, and C-H···π contacts. The catalytic activities of NHC Pd(II) complex 1 in three types of C-C coupling reactions (Suzuki-Miyaura, Heck-Mizoroki, and Sonogashira reactions) were studied. The results show that this catalytic system is efficient for these C-C coupling reactions.

An efficient class of bis-NHC salts: applications in Pd-catalyzed reactions under mild reaction conditions

This study describes an efficient class of bis-N-heterocyclic carbene (bis-NHC) salts that can be easily made from commercially available and inexpensive starting materials. The application of these salts to Pd-catalyzed reactions is described. The palladium (Pd) catalyst generated in situ was highly effective under mild reaction conditions.

This study describes an efficient class of bis-N-heterocyclic carbene (bis-NHC) salts that can be easily made from commercially available and inexpensive starting materials.

Crystal structure of {2,6-bis-[(di-methyl-amino)-meth-yl]phenyl-κ3N,C1,N'}(bromido/chlorido)-mercury(II)

In the mol-ecular structure of the title compound, {2,6-bis-[(di-methyl-amino)-meth-yl]phenyl-κ3N,C1,N'}[bromido/chlorido-(0.30/0.70)]mercury(II)-{2,6-bis-[(di-methyl-amino)-meth-yl]phenyl-κ3N,C1,N'}[bromido/chlorido-(0.24/0.76)]mer-cury(II) (1/1), [HgBr0.30Cl0.70(C12H19N2)]·[HgBr0.24Cl0.76(C12H19N2)], there are two mol-ecules in the asymmetric unit of formula LHgX {L = 2,6-bis-[(di-methyl-amino)-meth-yl]phenyl and X = Cl/Br}. In each mol-ecule, the halide site is mixed Cl/Br, with occupancies of 0.699 (7):0.301 (7) and 0.763 (7):0.237 (7), respectively. The two mol-ecules are linked into dimers by a combination of Hg⋯Hg [Hg⋯Hg = 3.6153 (3) Å] and C-H⋯Cl and C-H⋯π inter-actions.

Synthesis, structure and catalysis of a NHC–Pd(ii) complex based on a tetradentate mixed ligand

NHC–Pd(ii) complex 1 has been prepared. The catalytic activity of 1 in C–C coupling reactions was studied.

Structures of NHC Hg(ii) and Ag(i) complexes and selective recognition of nitrate anion

Eight N-heterocyclic carbene Hg(ii) and Ag(i) complexes were prepared, and the selective recognition of nitrate anion was studied.

A novel potentiometric self-plasticizing polypyrrole sensor based on a bidentate bis-NHC ligand for determination of Hg(ii) cation

In this approach, a new potentiometric self-plasticizing polypyrrole sensor was constructed based on a bidentate bis-NHC ligand for the purpose of Hg²⁺cation determination.

Antimicrobial Studies of N-Heterocyclic Carbene Silver Complexes Containing Benzimidazol-2-ylidene Ligand

Seven novel 4-vinylbenzyl substituted N-heterocyclic carbene (NHC) silver complexes were synthesized from different benzimidazolium salts and silver (I) oxide in dichloromethane at room temperature. These new 4-vinylbenzyl substituted NHC silver complexes were characterized by spectroscopic (NMR, IR) and elemental analysis techniques. Using the agar dilution procedure, the antimicrobial activities of these synthesized new compounds were investigated against Gram (+)/(−) bacterial and fungal strains. These NHC silver complexes showed effective activities against Escherichia coli, Pseudomonas aeruginosa (Gram-negative bacterial strains), Enterococcus faecalis, Staphylococcus aureus (Gram-positive bacterial strains), and Candida tropicalis and Candida albicans (fungal strains).