New relativistic quantum chemical methods for understanding light-induced therapeutics.

The inorganic platinum complexes currently in clinical use for cancer treatment have severe side effects, and complexes with fewer side effects are required. One option is to use complexes that are inactive until they are light-activated. Theoretical chemistry can contribute to the design of these complexes, but most current theoretical methods lack explicit treatment of relativistic effects (since the target complexes often contain heavy elements). In particular, spin-orbit coupling is required for accurate predictions of the complexes' photo-physical properties. In this perspective, we summarize relativistic methods developed in recent years that can contribute to our understanding of light-induced reactivity and thereby help predict new, suitable complexes.