It Takes Three to Tango - the length of the oligothiophene determines the nature of the long-lived excited state and the resulting photocytotoxicity of a Ru(II) photodrug.

A low-lying triplet intraligand state (3IL) determines the properties of the long-lived excited states in a series of Ru(II) complexes. The 3IL state can be accessed by increasing the length of an oligothiophene chain. The 3IL state is extremely efficient at generating 1O2 and thus enhances the potency of the complexes as PDT agents.