Mono-, di- and tri-dentate binding modes of a substituted isocytosine derivative in complexes of palladium and zinc

Abstract

The crystal and molecular structures of three metal complexes of the pyrimidine derivative, 1-(2-hydroxyethyl)-(2-aminoethyl-N²)-5-methylisocytosine reveal that, as a ligand, this heterocyclic base exhibited a diverse range of co-ordination modes. With zinc(II), monodentate co-ordination via the carbonyl oxygen of the pyrimidine base was observed. In the case of palladium(II), both a didentate mode, via endo- and exo-cyclic nitrogen donors, and a tridentate mode, involving exocyclic nitrogens and the alcohol oxygen donors, was observed. In the latter case the pyrimidine exists in the rare iminooxo tautomeric form.