Photoreaction pathways for the anticancer complex trans,trans,trans-[Pt(N-3)(2)(OH)(2)(NH3)(2)]

The photodecomposition of the anticancer complex trans, trans, trans-[Pt(N-3)(2)(OH)(2)(NH3)(2)] in acidic aqueous solution, as well as in phosphate-buffered saline (PBS), induced by UVA light (centred at lambda = 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 N-2 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 O-2 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.