Ternary Complexes of cis-(NH3)2PtCl2 (cis-DDP) With Guanosine (guo), Cytidine (cyd) and the Aminoacids Glycine (gly), L-Alanine (ala), L-2-Aminobutyric Acid (2-aba), L-Norvaline (nval) and L-Norleucine (nleu)

The ternary complexes of formulae cis-[(NH(3))(2)Pt(nucl)(amac)]NO(3), where nucl = guo and cyd (guanosine and cytidine) and amac = the deprotonated aminoacids glycine (gly), L-alanine (ala), L-2-aminobutyric acid (2-aba), L-norvaline (nval) and L-norleucine (nleu), were prepared from the reactions of the binary chelated ones cis-[(NH(3))(2)Pt(nucl)(amac)]NO(3) with the nucleosides.They were characterized by (1)H, (13)C and (195)Pt NMR and IR spectra, together with elemental analysis and conductivity measurements. The aminoacids coordinate with Pt(II) in the ternary complexes with their terminal -NH(2) groups, guo through N(7) and cyd through N(3). Ligand-ligand hydrophobic interactions were also observed in the ternary complexes and were stronger with longer aliphatic chains of the aminoacids. The (3)E sugar conformation increased by 5-7% in the ternary systems, as compared to the free nucleosides, while the percentage of the gg conformation remained almost constant and the one of the anti conformation of the sugar increased also slightly. Finally, the h conformer around the C(alpha)-C(beta) bonds of the aminoacids reached a maximum in the binary systems and decreased again considerably in the ternary ones.