Design, synthesis, and biological investigation of N-heterocyclic carbene –silver complexes for catalytic multicomponent coupling reactions

Benzimidazolium silver salts 2a–f, bearing two nitrogen atoms substituted with different alkyl groups, were synthesized in high yields. These salts were readily converted into the corresponding N-heterocyclic carbene (NHC) silver(I) complexes 3a–f. The solution structures of these complexes were determined by mean of conventional spectroscopic methods (¹H NMR, ¹³C{¹H} NMR, FTIR) and their molecular structures optimized using density functional theory (DFT) at B3LYP level. Enzyme inhibition and antioxidant assays revealed that the biological activity of the new Ag–NHC complexes 3a–f strongly depend on the nature of the NHC substituents. Molecular docking confirmed high binding affinities toward AChE, with interactions taking place at both the peripheral and catalytic anionic sites, while ADMET analysis predicted favorable pharmacokinetic and toxicity profiles. Finally, a mild and efficient A(Yılmaz et al., 2024³⁾-coupling protocol using 5,6-dimethylbenzimidazole-based NHC–silver(I) catalysts enabled the selective synthesis of propargyl amines.