1 research outputs found
Trifluoromethyl-Substituted Iridium(III) Complexes: From Photophysics to Photooxidation of a Biological Target
Photodynamic therapeutic agents are
of key interest in developing
new strategies to develop more specific and efficient anticancer treatments.
In comparison to classical chemotherapeutic agents, the activity of
photodynamic therapeutic compounds can be finely controlled thanks
to the light triggering of their photoreactivity. The development
of type I photosensitizing agents, which do not rely on the production
of ROS, is highly desirable. In this context, we developed new iridium(III)
complexes which are able to photoreact with biomolecules; namely,
our Ir(III) complexes can oxidize guanine residues under visible light
irradiation. We report the synthesis and extensive photophysical characterization
of four new Ir(III) complexes, [Ir(ppyCF<sub>3</sub>)<sub>2</sub>(N^N)]<sup>+</sup> [ppyCF<sub>3</sub> = 2-(3,5-bis(trifluoromethyl)phenyl)pyridine)
and N^N = 2,2′-dipyridyl (bpy); 2-(pyridin-2-yl)pyrazine (pzpy);
2,2′-bipyrazine (bpz); 1,4,5,8-tetraazaphenanthrene (TAP)].
In addition to an extensive experimental and theoretical study of
the photophysics of these complexes, we characterize their photoreactivity
toward model redox-active targets and the relevant biological target,
the guanine base. We demonstrate that photoinduced electron transfer
takes place between the excited Ir(III) complex and guanine which
leads to the formation of stable photoproducts, indicating that the
targeted guanine is irreversibly damaged. These results pave the way
to the elaboration of new type I photosensitizers for targeting cancerous
cells