Chiral-recognition polymer prepared by surface molecular imprinting technique

A highly enantioselective polymer was prepared by the surface molecular imp rinting technique for the separation of optically active tryptophan methyl ester. A synthetic host molecule (phenyl phosphonic acid monododecyl ester) was proved to be effective for recognizing the chirality of amino acid est ers. The L- or D-tryptophan methyl ester (TrpOMe)-imprinted polymer contain ing the functional host molecules revealed high enantioselectivity toward t he corresponding imprinted isomer. While, the racemic-TrpOMe-imprinted and unimprinted polymers did not show the enantioselectivity at all. These resu lts mean that the complementary binding sites such as 'template-fit pockets ', in which the position and the alignment of the functional group in the f unctional host molecule are optimally adjusted for binding the correspondin g imprinted isomer, are a principal factor to recognize the target molecule . These enantioselectivities were quantitatively supported by high binding constants for the corresponding imprinted isomer. To verify the recognition mechanism of the imprinted polymer, FT-IR and H-1-NMR measurement and comp utational modeling were conducted. Based on the results obtained, it was co ncluded that the enantiomeric selectivity is endowed by the electrostatic a nd hydrogen bonding interactions between the-functional molecule and the ta rget tryptophan methyl ester along with the chiral space formed on the poly mer surface. (C) 2000 Elsevier Science B.V. All rights reserved.