PROTON MAGNETIC RESONANCE STUDIES OF SELF-ASSOCIATION AND METAL COMPLEXATION OF NUCLEOSIDES IN DIMETHYL SULFOXIDE

For the purpose of deciding whether a ternary complex is formed on mixing a metal salt and two nucleosides, we have carried out proton magnetic resonance studies in which the metal salt is ZnCU and the nucleosides are adenosine (A), guanosine (G), cytidine (C), and uridine (U), in dimethyl sulfoxide medium. Although dimethyl sulfoxide is a hydrogen-bond acceptor, we take as reference state the one in which the nucleoside is bonded to solvent and look for further shifts of NH, NH2, and CH proton signals at different temperatures as the nucleoside concentration is increased and as an increasing amount of ZnCl2 is added. Formation constants of 1:1 Zn-nucleoside complexes are obtained. Of the four nucleosides studied, the ternary complexes formed are Zn-A-G and Zn-A-C. © 1968, American Chemical Society. All rights reserved.