Abstract

ROSETE-LUNA, Sharon; MEDRANO, Felipe; BERNAL-URUCHURTU, Margarita I.  and  GODOY-ALCANTAR, Carolina. Crown Ether Ditopic Receptors for Ammonium Salts with High Affinity for Amino Acid Ester Salts. J. Mex. Chem. Soc [online]. 2009, vol.53, n.4, pp.209-219. ISSN 1870-249X.

Two bis crown ether receptors were synthesized and tested as host molecules for protonated forms of alkyl amines and amino acid esters. Molecular recognition studies were conducted in CH₂Cl₂:MeOH (92:8) by spectrophotometric UV/Vis titrations and by spectrometric ¹H NMR titrations in CDCl₃. The calculated binding constants are in the range 10²-10⁵ M^-1. A high affinity for L-amino acid methyl ester derivatives was found. A theoretical study at the DFT level of the synthesized receptor and some analog ligands with three different ammonium ions helps to rationalize the experimentally found trends.

Keywords : Ditopic Receptors; Binding Constant; Crown Ethers; Alkyl Ammonium; Amino Acid.

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