Platination of the exocyclic amino group of the adenine nucleobase by Pt-II migration

Migration of coordinated Pt-II from the endocyclic N(1) site to the exocycl ic nitrogen atom in 9-methyladenine occurs at high pH values. The resulting N(6)-platinated complex has been characterized by X-ray crystal structure analysis and by H-1- and Pt-195-NMR spectroscopy. The H-1-NMR spectra show that the Pt-II(dien) unit at N(6) can adopt either a syn or an anti conform ation with respect to the N(1) site, and that protonation of the ring nitro gen atoms N(1) and/or N(7) perturbs the syn/anti equilibrium.