Photoactivatable diazido Pt(IV) anticancer complex can bind to and oxidize all four nucleosides.

Photoactivatable diazidodihydroxido Pt(iv) complex trans,trans,trans-[Pt(N3)2(OH)2(py)2] (1; py = pyridine) is a promising anticancer agent which can be activated by visible light to induce cancer cell death. DNA has been thought to be involved in the mechanism of action of this kind of Pt(iv) prodrug. However, the detailed photodecomposition pathways of complex 1 and its interaction modes with DNA are complex. Herein we report that upon light irradiation complex 1 can bind to all four nucleosides covalently with the reduced Pt(ii) species. Moreover, apart from the covalent coordination, various oxidation adducts of these four nucleosides induced by the reactive oxidative species (ROS) generated during the photoactivation of the complex 1 have also been identified, especially the induced oxidation of adenosine and cytidine which was firstly reported for this kind of photoactivatable Pt(iv) prodrug. Such dual-action may contribute to the highly potent photo-antiproliferativity of complex 1 towards cancer cells, which may account for the unique mechanism of action of the photoactivatable diazido Pt(iv) anticancer complexes.