N-Heterocyclic carbene as privileged scaffold in medicinal inorganic chemistry

The successful development of cisplatin in clinical use inspired research on metallic complexes as therapeutic agents for cancer diseases. Among them, N-heterocyclic carbenes (NHCs), which serve as a privileged scaffold, can stabilize a variety of transition metals through covalent metal-NHC bonds. These particular characteristics enabled metal-NHC complexes to be developed as clinical drug candidates. Studies demonstrated that metal-NHC complexes exhibited excellent anticancer bioactivities, which encouraged inorganic medicinal chemists to discover and develop novel metal-NHC complexes for cancer treatment. This chapter summarizes the anticancer bioactivities and mechanisms of platinum, rhodium, gold, and silver NHC complexes and provides novel therapeutic strategies for cancer treatment.