Ion Channel-like Crystallographic Signatures in Modified Guanine–Potassium/Sodium Interactions

This communication describes crystallographic details of structures reminiscent of ion channels, formed from regioisomeric N7 and N9 guanine-carboxylate conjugates with potassium/sodium ions and their subsequent STM observations on Au(111) surface. Ion channel-like crystal structures were obtained with the observation of a notable shift in metal ion coordination from carbonyl to carboxylate oxygen. These results are expected to provide insight into competing sites for modified guanine–metal coordination, an entry into guanine-based ion channels and a route toward guanine-functionalized surfaces.