Synthesis and cytotoxic characteristics displayed by a series of Ag( i )-, Au( i )- and Au( iii )-complexes supported by a common N-heterocyclic carbene

The synthesis, structures and anticancer studies of a series of precious metal complexes supported by 1-methyl-2-(phenyl)imidazo[1,5- a ]pyridine-2-ylidene ( 1 ) have been highlighted. The Ag( i ) ( 2 ), Au( i ) ( 3 ) and Au( iii ) ( 4 ) complexes were prepared using standard methods and characterized by a range of techniques, including NMR spectroscopy, X-ray crystallography and elemental analyses. The in vitro cytotoxicity activities displayed by 2–4 were explored against human colon adenocarcinoma (HCT116), lung cancer (A549) and breast cancer (MCF7) cell lines. A series of assays showed that all of the complexes exhibited significant growth inhibition in the aforementioned cell lines. Inspection of the data collected revealed that the Au( i ) and Ag( i ) complexes were more potent than their Au( iii ) congener, a trend that was found to be consistent with molecular docking studies that utilized BCL-2 as a model as this protein regulates cell death through apoptosis.