New mechanisms in DNA cleavage by metal complexes

The chemistry of new families of DNA cleavage agents based on oxoruthenium(IV) or diplatinum pyrophosphite complexes is reviewed. The ruthenium complexes derived from Ru(tpy)(bpy)O²⁺ (tpy, 2, 2, 2-terpyridine; bpy, 2, 2-bipyridine) are effective DNA cleavage agents both electrocatalytically or thermally. The stoichiometric reaction quantitatively produces Ru(II), which also binds to DNA covalently in a slow, follow-up reaction. The cleavage by Pt₂(pop)₄ ^4– (pop, P₂O₅H₂) is photoactivated and proceeds via H-atom abstraction by the platinum complex.