The interaction of H⁺, Zn²⁺, and Cu²⁺ with adenine and guanine

Abstract

The interactions of H⁺, Zn²⁺, and Cu²⁺ with adenine and guanine have been investigated by N.M.R. studies in dimethyl sulphoxide (Me₂SO). The compounds Zn(adenine)HCl₃, Zn(guanine)HCl₃, (adenine)HCl, (adenine)2HCl, (guanine)HCl,H₂O and (guanine-H)₂[ZnCl₄]4H₂O have also been prepared and studied in Me₂SO. The last compound as well as (adenine)2HCl have not been reported previously. N.m.r. spectra are concentration-dependent and also depend upon the hydrogen ion activity. This work has shown that there is little correlation between solid state structures and interactions in solution and, further, that selective line broadening by the para- magnetic Cu²⁺ ion is not unequivocally diagnostic of the binding site in these systems.