Polypyridyl Ru(II) complexes have long been studied for use in a wide range of applications due to their rich excited state photochemistry. Currently, they are of great interest for use in photochemotherapy (PCT) applications because of their ability to dissociate ligands in a controlled manner after irradiation. This ability to utilize light to generate the bio-active species affords a great deal of spatiotemporal control over its delivery. Generally, Ru(II) complexes towards this application employ sterically-bulky ligand sets to enhance ligand loss by lowering the energy of the triplet ligand-field (3LF) states thought to be responsible for ligand photodissociation. However, other excited state factors besides simply the relative energy of the 3LF states may need to be considered in order to design complexes with high quantum yields of ligand photodissociation. Herein, we report the photochemical, computational and spectroscopic investigation of two series of relatively unstrained Ru(II) complexes, containing either the terpyridine ligand or a tetradentate caging ligand. The role of the 3LF states in these complexes will be discussed, as well as other components of their electronic structure that may play an important role in ligand photodissociation.

Investigating the role of excited-state mixing in ligand photodissociation from polypyridyl Ru(II) complexes

254th National Meeting (2017)

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