EQUILIBRIUM STUDY ON BINARY COMPLEXES OF Cu(II), Ni(II) Co(II) and Mg(II) WITH NUCLEIC ACID BASES

TLDR: In this paper, the acid dissociation constants of the above ligands are reported at 30 and 60° together with the thermodynamic parameters involved in their dissociation reactions, in general the first dissociation is favourable and the stability of the 1:1 metal complexes decreases in the order Cu(II) < Ni(II), Co(III) < Mg(II).

Abstract: Formation constants of 1:1 binary complexes of Cu(II), Ni(II), Co(III) and Mg(II) with nucleic acid bases such as adenine, 8-azaadenine, cytosine and uracil are reported at 30° at an ionic strength of 0.1M (KNO3). The acid dissociation constants of the above ligands are reported at 30 and 60° together with the thermodynamic parameters involved in their dissociation reactions. In general the first dissociation is favourable and the stability of the 1:1 metal complexes decreases in the order Cu(II) < Ni(II) < Co(II) < Mg(II). There is a good correlation between the basicity of the ligands and the stability of the 1:1 metal complexes. No significant interaction is observed in the case of uracil with any of the metal ions investigated.