Solution properties and DNA binding of Rh(III)-ciclopentadienyl-pyridinyl-quinoline complex

Among the wide efforts devoted by the scientific community to the design of new drugs with enhanced properties, studies have also focused on half-sandwich Rh(III) anticancer complexes, which can attack biosubstrates or perturb the redox status of cells. In this frame, thanks to the long lasting collaboration between our groups, we are performing studies on the mechanistic aspects of the binding of especially devised metal complexes to biosubstrates as DNA, RNA and proteins. In this work, we studied the interaction between the Iridium complex shown in Figure 1 and DNA. The chloride exchange process to give Rh-H₂O from Rh-Cl was assessed together with the acidity constants of Rh-H₂O. Then, the possible binding reaction of the two species Rh-H₂O and Rh-OH¯ with DNA was analysed making use of different approaches ranging from spectrophotometry, viscometry, circular dichroism until stopped-flow kinetics. The obtained results indicated that the interaction does indeed occur and its different features will be discussed.