Substituent effects on a binaphthyl-linked zinc bisporphyrinate host: Modulating chirality sensing and circular dichroism response in the enantioselective recognition of amino acid esters

A new binaphthyl-linked zinc bisporphyrinate host, bearing ethoxy substituents, was designed and synthesized to investigate the substituent effect on chiral recognition. This host was evaluated for its enantioselective binding towards various amino acid ethyl esters using circular dichroism (CD), UV-Vis spectroscopy, and 1 H NMR titration. The host demonstrated effective enantiomeric discrimination of amino acid esters via CD signals. However, the intensity ratio between the L- and D-enantiomers