Abstract/Summary

Ruthenium polypyridyl complexes have been intensively studied in many laboratories around the world for their potential applications in chemotherapy, including photodynamic therapy, and as useful DNA probes and sensors in cells. This chapter discusses the ways in which X-ray crystallography can contribute to our understanding of these applications at the molecular level. The design of useful compounds relies on assumptions about the shape and possible flexibility of the molecular target, and an appreciation of how and why a small change in the molecular design can have a major impact on the effectiveness of the compound.