Solution and solid study of Zn(II) and Cd(II) complexes with N-(6-amino-3,4-dihydro-3-methyl-5-nitroso-4-oxo-pyrimidin-2-yl)-glycine as ligand.: Crystal structures of [ZnL2(H2O)4]•6H2O and {[Cd(μ-L)Cl(H2O)2]•H2O}n

Reactions of N-(4-amino-1,6-dihydro-1-methyl-5-nitroso-6-oxo-pyrimidin-2-yl)glycine with Zn(II) and Cd(II) (1:1 and 1:4 metal/ligand ratios, in aqueous media at 35 degrees C and 0.1 M KCI ionic strength) were studied by potentiometric methods. This study has revealed a similar qualitative behaviour to that found by us for this family of N-pyrimidine aminoacids, the primary coordination site being either the pyrimidine or the carboxylate group depending on whether the ligand acts in neutral form or deprotonated, respectively. In solid state two complexes were obtained by working in 1:1 metal-to-ligand ratio: [Zn(L)(2)(H2O)(4)]. 6H(2)O and {[Cd(mu-L)Cl(H2O)(2)]. H2O)(n), which were characterised by IR and NMR spectroscopies, TG and DSC techniques and single crystal X-ray diffraction. The former complex is mononuclear with the Zn(II) ion hexacoordinated in a distorted octahedral geometry. The coordination sphere is formed by four water molecules and two ligands coordinating in a monodentate fashion through the carboxylate group. The Cd(II) complex consists of a 1D infinite chain, with the metal ion heptacoordinated in a distorted pentagonal bipyramid. The ligand bridges the metal ions coordinating in a bis-didentate fashion through the pyrimidine and the carboxylate group. The nature of these complexes is very different to that shown by the Zn(II) and Cd(II) complexes with the related methionine derivative, which is attributed to he effect of the R substituent on the aminoacid moiety. (C) 2000 Elsevier Science S.A. All rights reserved.