Chiral recognition of amino acid esters by a novel oxalic amide-linked bisporphyrin

Abstract

A novel oxalic amide-linked bisporphyrinate 1has been designed and synthesized, which shows chiral recognition ability for amino acid ethyl esters. The structure of complex 1·(D-Phe-OEt)(L-Phe-OEt) has been solved by X-ray crystallography. It reveals the following information: bisporphyrin unit adopts anti-configuration; compound 1forms 1: 2 complex with amino acid ethyl esters; one important hydrogen bond is formed between the coordinated nitrogen of amino acid ester and carbonyl oxygen in the amide group. The chiral recognition mechanism has been further investigated by UV-Vis spectra, (1)H NMR and DFT/TDDFT calculations.