Polynuclear Ag(I)-N-heterocyclic carbene complexes: synthesis, electrochemical and in vitro anticancer study against human breast cancer and colon cancer

Abstract

Four new bis-imidazolium salts 3–6 and their di- and polynuclear silver(I)–N-heterocyclic carbene (Ag(I)–NHC) complexes 7–10 were synthesized and characterized by using various analytical techniques. Single-crystal studies of 8 revealed a dinuclear structure whereas that of 9 revealed an interesting polynuclear structure. The quasi-reversibility of redox events in electrochemical study of 9 indicated that reduction produces unstable decomposed species and oxidation may be ascribed to these decomposed species. All the compounds were studied for their in vitro anticancer study against human breast cancer (MDA-MB-231) and colon cancer (HCT-116) cells. The study revealed that Ag(I)–NHC complexes are comparatively more potent than NHC precursors (salts). MDA-MB-231 cells appeared more sensitive to complexes than HCT-116 cells while reverse is the case for NHC salts.