Rh(III) and Ir(III)-ciclopentadienyl-pyridinyl-quinoline complexes: solution properties and polynucleotides binding

Nowadays, an active research area is focused on the development of new metallodrugs capable of interacting with DNA, and organometallic complexes are promising candidates to this aim. In the frame of our long lasting collaboration and of the study of the interaction of small molecules with DNA and RNA, the binding of newly synthesized Ru-arene complexes to biosubstrates was already analysed. This contribution reports on the preliminary analysis of the binding of rhodium and iridium complexes to biosubstrates as, in particular, double stranded DNA and RNA. First, the properties of the metal complexes themselves were analysed, with particular focus on the chloride exchange process to give the M-H2O species and on the evaluation of the pKA of the M-H2O = M-OH equilibrium. Then, analysis of the possible binding reaction of M-H2O and M-OH towards polynucleotides is done using spectrophotometry, viscometry, circular dichroism and stopped-flow kinetics. The preliminary results obtained suggest different binding features that will be discussed.