Photoreaction pathways for the anticancer complex trans,trans,trans-[Pt(N3)2(OH)2(NH3)2]

The photodecomposition of the anticancer complex trans,trans,trans- [Pt(N3)2(OH)2(NH3)2] in acidic aqueous solution, as well as in phosphate-buffered saline (PBS), induced by UVA light (centred at λ = 365 nm) has been studied by multinuclear NMR spectroscopy. We show that the photoreaction pathway in PBS, which involves azide release, differs from that in acidic aqueous conditions, under which N2 is a major product. In both cases, a number of trans-{N-Pt(ii/iv)-NH3} species were also observed as photoproducts, as well as the evolution of O2 and release of free ammonia with a subsequent increase in pH. The results from this study illustrate that photoinduced reactions of Pt(iv)-diazido derivatives can lead to novel reaction pathways, and therefore potentially to new cytotoxic mechanisms in cancer cells.