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)]center dot 6H(2)O and {[Cd(mu-L)Cl(H2O)(2)]center dot 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 aqueou s media at 35 degrees C and 0.1 M KCI ionic strength) were studied by poten tiometric 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 dep ending on whether the ligand acts in neutral form or deprotonated, respecti vely. 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 techni ques and single crystal X-ray diffraction. The former complex is mononuclea r with the Zn(II) ion hexacoordinated in a distorted octahedral geometry. T he coordination sphere is formed by four water molecules and two ligands co ordinating in a monodentate fashion through the carboxylate group. The Cd(I I) complex consists of a 1D infinite chain, with the metal ion heptacoordin ated in a distorted pentagonal bipyramid. The ligand bridges the metal ions coordinating in a bis-didentate fashion through the pyrimidine and the car boxylate group. The nature of these complexes is very different to that sho wn by the Zn(II) and Cd(II) complexes with the related methionine derivativ e, which is attributed to he effect of the R substituent on the aminoacid m oiety. (C) 2000 Elsevier Science S.A. All rights reserved.