New weapons to fight cancer are constantly needed. Among chemotherapeutics, anti-cancer metal-drugs have enjoyed a long and successful history since the discovery of the benchmark cisplatin. Advances in metal-drug discovery have motivated chemists to build plethora of complex structures. Among them, a novel area is emerging. This article presents a survey of the metal-N-Heterocyclic Carbenes (Ag(I), Au(I), Pd(II) and Cu(I)-NHCs) as potential anti-cancer agents. Most of the metal-NHCs considered display higher cytotoxicities than the reference metallo-drug cisplatin. Some of them are even selective for particular cell lines. Their mechanisms of action at the cellular level are further discussed, showing that the nature of the metal is of great importance. All these promising results demonstrate that this approach deserves more attention and work.

This critical review is an updated survey of metal-carbenes as potential anticancer chemotherapeutics. We report on the recent advances in the discovery of N-heterocyclic carbenes, acyclic diamino carbenes and abnormal NHCs associated with metals from groups 10 and 11 that displayed antiproliferative activity and emphasize, when possible, their molecular target(s) and their mechanism of action.