Compounds of Silicon and Homologues, 127 Unsaturated Compounds of Silicon and Homologues, 54 Tetrasupersilyl-tristannaallene and -tristannacyclopropene (tBu3Si)4Sn3 - Isomers with the Shortest Sn=Sn Double Bonds to Date

Migration of coordinated PtII from the endocyclic N(1) site to the exocyclic 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 1H- and 195PtNMR spectroscopy. The 1H-NMR spectra show that the PtII(dien) unit at N(6) can adopt either a syn or an anti conformation with respect to the N(1) site, and that protonation of the ring nitrogen atoms N(1) and/or N(7) perturbs the syn/anti equilibrium.