Enantioselective Discrimination of l-Phenylglycine Ethyl Ester through Supramolecular Assembly with a Binaphthyl-Linked Zinc Bisporphyrinate Host

Abstract

Chiral discrimination of amino acid stereoisomers is essential for biological processes and pharmaceutical development. Bisporphyrins represent promising candidates for the chiral recognition of amino acid derivatives. Herein, we report a rationally designed binaphthyl-linked zinc bisporphyrinate complex demonstrating remarkable enantioselective binding toward l-phenylglycine ethyl ester (L-PhgOEt). The complex demonstrates a 19-fold amplification in circular dichroism (CD) response intensity for L-PhgOEt over its d-enantiomer, with quantified enantioselectivity (L/D = 4.8), reflecting good chiral recognition capabilities. Single-crystal X-ray analysis unveils a multimodal recognition mechanism involving (i) axial coordination to zinc centers, (ii) hydrogen bonding interactions with amide functionalities, and (iii) π-system stabilization through both C–H···π and O···π interactions with the methoxy-functionalized binaphthyl linker. This synergistic combination of coordination bonds and noncovalent interactions establishes bisporphyrins as tailorable chiral receptors and guides the design of biomimetic systems for pharmaceutical applications.