TERNARY COMPLEXES OF CISPLATIN WITH AMINO-ACIDS AND NUCLEOBASES - THE CRYSTAL-STRUCTURE OF CIS-[(NH3)2PT(1-MEC-N3)(GLY-N)](NO3).2H2O

Ternary complexes of Pt(II) with the amino acids = amacH, glycine = GlyH, L-alanine = AlaH, L-2-aminobutyric acid = 2-AbaH, L-valine = ValH and L-norvaline = nValH and the nucleobases, 1-methylcytosine = 1-MeC and 9-methylguanine = 9-MeG were prepared in aqueous solutions via two synthetic routes: by reacting the binary complexes, either cis-[(NH3)2Pt(amac)](NO3) with 1-MeC or 9-MeG (route 1)), or the cis-[(NH3)2Pt(nucleobase)Cl](NO3) with the amino acids. Complexes of the following formulae were isolated as solid adducts: cis-[(NH3)2Pt(1-MeC)(Gly)](NO3), cis-[(NH3)2Pt(1-MeC)(Ala)](NO3), cis-[(NH3)2pt(1-MeC))2-aba)](NO3), cis-[(NH3)2Pt(1-MeC)(Val)](NO3), cis-[(NH3)2Pt(1-MeC)(nVal)](NO3) (not obtained analytically pure), cis-[(NH3)2Pt(9-MeG)(Gly)](NO3), cis-[(NH3)2Pt(9-MeG)(Ala)](NO3), cis-[(NH3)2Pt(9-Meg)(2-Aba)]NO3), cis-[(NH3)2Pt(9-MeG)-(Val)](NO3) and cis-[(NH3)2Pt(9-MeG)(n-Val)](NO3). These were characterized by elemental analysis, conductivity measurements and IR, Raman and H-1 NMR spectra. The results show that the amino acids are monodentate (coordination through NH2) and their carboxylate groups are deprotonated. The nucleobases coordinate through N(3) (1-MeC) and N(7) (9-MeG). Hindered rotation was also observed in the case of the ternary complexes with 1-MeC, in D2O solutions persisting up to 90-degrees-C. A cis-trans isomerization was also taking place in solution, increasing with temperature. A hydrophobic ligand-ligand interaction was detected to take place between the amino acid with aliphatic side chains (starting with 2-Aba), and the nucleobase ring systems, by H-1 NMR spectroscopy in aqueous solution, increasing with increasing length of the aliphatic side chain. Finally the crystal structure of the complex cis-[(NH3)2Pt(1-MeC)(Gly)](NO3) was solved by X-ray diffraction: space group P1BAR (No. 2), triclinic, a = 7.495(3), b = 16.388(4), c = 6.846(3) angstrom, alpha = 97.58(3), beta = 104.86, >> gamma = 102.05(3)-degrees, V = 779.5(6) angstrom 3, Z = 2. A weak Pt interaction with the O(2) of 1-MeC was observed as in other similar cases. No hydrophobic ligand-ligand interactions were found, however, in this complex, as expected.