Molecular recognition of a-amino acid esters with arylporphyrin zinc complexes

The recognition ability of 10 arylporphyrin zinc complexes with respect to glycine, a-alanine, and leucine methyl esters in toluene at 20degreesC was studied by spectrophotometric titration. The formation of amino acid-porphyrin associates, depending on the substitution pattern in the macroring, was examined by H-1 NMR spectroscopy. ne zinc complex with diarylporphyrin having hydroxy groups in the para positions of the benzene rings was found to be the best recognizing agent with respect to glycine methyl ester, while leucine methyl ester was recognized best by the complex with hydroxy groups in the ortho positions of the benzene rings.