15N and 199Hg magnetic resonance spectral investigation of inosine protonation and diamagnetic metal ion complexation

On the basis of complexation induced 15N chemical shift changes, the nucleoside inosine is shown to protonate preferentially at the N-7 site. This nitrogen is also favoured by Zn+2 and Hg+2 ions. 199Hg shifts support the notion that the binding of the first equivalent of Hg+2 is site selective.