Silver(I), Gold(I) and Gold(III)-N-Heterocyclic carbene complexes of naphthyl substituted annelated ligand: Synthesis, structure and cytotoxicity

The new type of annulated imidazolium salt 1-naphthyl-2-pyridin-2-yl-2H-imidazo[1,5-a]pyridin-4-ylium hexafluorophosphate (1·HPF6) and three novel N-heterocyclic carbene complexes (NHCs) [Ag(1)2][PF6] (2), [Au(1)2][PF6] (3), and [Au(1)Cl3] 4 have been synthesized and characterized by different spectroscopic techniques. The solid state structure of 2 has been determined by single crystal X-ray diffraction studies. The complex 3 has been synthesized via trans-metallation, whereas complex 4 was obtained via a disproportionation process. The cytotoxicities of the complexes 2, 3 and 4 were tested in vitro against non-small lung carcinoma (A549), colorectal carcinoma (HCT-116) and breast adenocarcinoma (MCF-7) cell lines. The measured IC50 values showed that the Au (I) complex 3 is more potent than the complexes 2 and 4 as well as cisplatin.