Binary and Ternary Nucleoside Complexes of Bivalent Metal Ions in Solution

Badar Taqui Khan and Ch. Abraham Lincoln*

Department of Chemistry, P.G. College of Science, O.U., Saifabad, Hyderabad -500 004 (India)

The stability constant for 1:1, 1:2 metal nucleosides and 1:1:1 mixed ligand complexes containing adenosine as primary ligand and cytidine, uridine and thymidine as secondary ligands are reported as 35° and μ = 0.1 M (KNO3). The metal ion studied are Cu(II), Ni(II), Co(II), Zn(II), Mg(II), and Ca(II). It is observed that the D log K values (difference in the stabilities of 1:2 and 1:1 complexes) for metal-adenosine are positive and for metal-thymidine are negative as expected from statistical consideration. The higher stability for the ternary systems are attributed to the stacking interaction of the ligands in the complexes.

Binary; ternary complexes; Nucleosides