The reactivity of N-2-(4-amino-1,6-dihydro-1-methyl-5-nitroso-6-oxo-pyrimidinyl)-L-histidine towards silver(I) and zinc(II) ions

Reactions of N-2-(4-amino-1,6-dihydro-1-methyl-5-nitroso-6-oxopyrimidinyl)-L-histidine with AgI and ZnII ions in 1/1 and 4/1 ligand-to-metal molar ratios, in aqueous media at 25 °C and 0.1 M KNO3 and KCl ionic strength, respectively, were followed by potentiometric techniques in order to determine formation equilibria for the complex species. The spectral curves, as a function of ligand-to-metal molar ratio at established pH values, were studied and four solid phases of stoichiometry: AgL·4H2O, Ag(HL)NO3·1.5H2O, AgL(OH)2K2·H2O and Zn(HL)2Cl2·7H2O were isolated and characterised by analytical, spectroscopic and thermal measurements.