ELECTROCHEMICAL AND F-19 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 F-19 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 ail amino acid in its zwitterionic form is demonstrated by F-19 NMR spectroscopy in aqueous media.