Sulfonated N-heterocyclic carbine-silver (I) complexes: Synthesis, characterisation and biological evaluation

The synthesis, characterisation and biological activity of water-soluble Ag(I)-NHC complexes, general formula Na[(NHC)AgCl] where NHC is a sulfonated and sterically hindered N-heterocyclic carbene, is reported. The Ag-NHC complexes (2a-e) were synthesised by reacting the corresponding sulfonated NHC ligands with Ag2O in the presence of NaCl or NaBr in methanol/water (1:1) solution. Synthesised silver (I)-N-heterocyclic carbene complexes have been characterised by NMR, micro-analysis and HRMS spectroscopic methods. The IC50 values of these complexes were determined by a proliferation BrdU enzyme-linked immunosorbent assay (ELISA) against HeLa (human cervix carcinoma), HT29 (human adenocarcinoma) and L929 (mouse fibroblast) cell lines. These complexes have been highlighted as promising and original platforms for building new types of metalodrug. All new water-soluble Ag(I) complexes demonstrated remarkable cytotoxic activity against HeLa, HT29 and L929 cell lines.