Metallointercalators and Metalloinsertors: Structural Requirements for DNA Recognition and Anticancer Activity.

As the carrier of the inheritable information in cells, DNA has been the target of metal complexes for over 40 years. In this chapter, the focus will be on non-covalent recognition of the highly structured DNA surface by substitutionally inert metal complexes capable of either sliding in between the normal base pairs as metallointercalators or flipping out thermodynamically destabilized mispaired nucleobases as metalloinsertors. While most of the compounds discussed are based on ruthenium(II) and rhodium(III) due to their stable octahedral coordination environment and low-spin 4d6 electronic configuration, most recent developments of alternative metal complexes, based on both transition metals and main group elements, will also be highlighted. A particular focus of the coverage is on structural data from X-ray structure analysis, which now provides details of the interaction at unprecedented details and will enable development of novel DNA binding probes for fundamental studies as well as new anticancer drug candidates.