Photoadduct between tris(1,4,5,8-tetraazaphenanthrene)ruthenium( II ) and guanosine monophosphate–a model for a new mode of covalent binding of metal complexes to DNA

Visible light irradiation of [Ru(TAP)3]2+(TAP = 1,4,5,8 -tetraazaphenanthrene) in aqueous solutions containing 5′-guanosine-monophosphate (GMP) and subsequent treatment with 1 mol dm–3 HCl yields Ru(TAP)2(2-TAP-G)2+, in which the guanine moiety is bound via N-2 to C-2 of one of the TAP ligands.