Electrochemical and 19F NMR detection of anions, ion-pairs, and a zwitterionic amino acid with a ferrocene-based hetero-ditopic receptor bearing o-(carboxamido)trifluoroacetophenone and crown-ether ligands

Abstract

Described are the electrochemical and 19F NMR detection of anions, ion-pairs, and zwitterionic L-phenylalanine with the ferrocene-based hetero-ditopic receptor. A cyclic voltammetric study shows that the receptor induces a positive shift in the ferrocene oxidation potential upon binding of a potassium cation, whereas it induces a negative shift upon binding of an acetate anion, both of which can be reversed. Also, the redox potential shifts were dependent on ion-pairing interactions. Furthermore, direct detection of an amino acid in its zwitterionic form is demonstrated by 19F NMR spectroscopy in aqueous media.