Platinum(ii) and palladium(ii) complexes with methyl 3,4-diamino-2,3,4,6-tetradeoxy-α-l-lyxo-hexopyranoside

Abstract

To develop new complexes of Pt(II) and Pd(II) that have ligands in a shape complementary to DNA, we designed and synthesized a methyl 3,4-diamino-2,3,4,6-tetradeoxy-α-L-lyxo-hexopyranoside (V). This synthetic ligand imitates the shape of daunosamine, a DNA minor groove binding sugar moiety present in the antineoplastic anthracycline antibiotics doxorubicin and daunorubicin. Ligand V, was used to form the Pt(II) and Pd(II) chloride complexes [MCl₂(V)] 1, 2, 3, and 4, which have potential antitumor properties. We characterized these complexes by X-ray diffraction and in solution by ¹H-, ¹³C-, ¹⁵N- and ¹⁹⁵Pt-NMR. Both Pt(II) and Pd(II) complexes seem to be isostructural, as shown by X-ray diffraction and molecular modeling. The complexes formed dimers in the crystal lattice with short M–M and Cl⋯N(H) hydrogen bonds. Detailed dynamic NMR studies in CD₂Cl₂ and CD₃CN solutions confirm the monomeric structure in both solvents as well as solvation around the metal and intermolecular hydrogen bonding of NH in CD₃CN.