Ion-Pairing Stereodynamic Probes for Circular Dichroism Chiral Sensing of Amines

Tris(2-pyridylmethyl)amine (TPMA) and tris(2-phenolmethyl)amine (TPA) metal complexes have been extensively used for catalysis and molecular recognition applications. In particular, due to their ability to form stereodynamic complexes through the helical arrangement of the ligand around the metal in a propeller shape, chiroptical sensing has been extensively investigated. In particular, the capability of the analyte, usually a Lewis base, to bind the metal complex has been the predominant recognition motif. Herein, we report the synthesis and application of a zinc TPA-based stereodynamic probe for the sensing of chiral amines and amino-alcohols in which an ion-pair interaction between the anionic metal complexes and the ammonium ions is responsible for the recognition.