Targeting G-rich DNA Structures with Photo-Reactive bis-Cyclometalated Iridium(III) Complexes

In this work, we report on the synthesis and the characterisation of three novel iridium(III) bis-cyclometalated complexes. Their photophysics has been fully characterized by classical methods and revealed charge transfer (CT) and ligand centered (LC) transitions. Their ability to selectively interact with G-quadruplex telomeric DNA over duplex DNA has been studied by Circular Dichroism (CD), Bio Layer Interferometry (BLI) and Surface Plasmon Resonance (SPR) analyses. Interestingly, one of them is able to perform photo-induced electron transfer (PET) with guanine DNA base, which can in turn lead to oxidative damage (such as 8-oxo-guanine) to the telomeric sequence. To the best of our knowledge, this is the first study of highly photo-oxidant bis-cyclometalated iridium(III) complexes towards G-quadruplex telomeric DNA. 2