A mass spectrometric investigation of the reaction between 4,4′-vinylenedipyridine bis[2,2′ : 6′,2″-terpyridine platinum (II)] and the self-complementary oligonucleotide d(CpGpTpApCpG) Original Research Article

4,4′-Vinylenedipyridine bis[2,2′ : 6′,2″-terpyridine platinum(II)], a potential intermolecular bis-intercalator of DNA, reacts slowly at PtII, the linker being displaced by nucleobases. Crystallization of 4,4′-vinylenedipyridine bis[2,2′ : 6′,2″-terpyridine platinum(II)] in the presence of the self-complementary oligonucleotide d(CpGpTpApCpG) gave a product which was analyzed by electrospray ionization mass spectrometry. Molecular mass measurements demonstrated ligation of one terpyridine PtII, which was shown by liquid chromatography—mass spectrometry to reside exclusively on deoxyguanosine. The terpyridine PtII was shown by tandem mass spectrometry to be attached to the 3′-terminal deoxyguanosine, consistent with N-7 substitution.