Binary and ternary complexes of inosine

Formation of binary and ternary complexes of Cu(II) and NI(II) metal ions with inosine as a primary ligand and some biologically important aliphatic and aromatic carboxylic acids (succinic, oxalic, malic, maleic, malonic, tartaric, 5-sulfosalicylic, salicylic and phthalic acids) as secondary ligands was studied by the potentiometric technique at 25 degrees C and 0.10 M (NaNO3) ionic strength. The ternary complex formation was found to take place in a stepwise manner. The stability constants of these binary and ternary systems were calculated, The lower stability of 1:2 complexes of inosine compared to the corresponding 1:1 systems is in accord with statistical considerations. The values of Delta log K for the ternary complexes studied have been evaluated and discussed. The mode of chelation of ternary complexes was ascertained by conductivity measurements. (C) 1998 Elsevier Science B.V. All rights reserved.