Ag+ Selection by Aza-18-crown-6 Ethers N-Substituted on Heterocyclic Aromatics.

Substitution on the nitrogen atom, where necessary by high-pressure SNAr reactions, of aza-18-crown-6 ethers linked to heterocyclic aromatics has extended the number of potential host compounds for Ag+. The complexation of Ag+ by the new compounds has been evaluated by liquid membrane ion transport and ion extraction experiments. The nature of the binding sites of these new host compounds for Ag+ has been assessed, in DMF/D2O (4/1), by 13C nmr titration experiments with AgClO4.