Synthesis, Secondary Structure and Anion Binding of Acyclic Carbohydrate-derived Oligo(amide-triazole)s

DANIELA M. FIDALGO; MARÍA EUGENIA MONGE; OSCAR VARELA; ADRIANA A. KOLENDER

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2018 vol. 2018 p. 6787 - 6799

1434-193X

A family of linear, carbohydrate-derived oligo(amidetriazole)s has been designed and synthesized. These moleculespossess a regular distribution of triazole rings (from one to four)linking the carbohydrate units to give dimer to pentamer derivatives.Their binding to halide anions was qualitatively analyzed by meansof NMR spectroscopy and mass spectrometry. All the compoundswere able to bind chloride anions, with a stoichiometry thatdepended on the chain length. The dimer and trimer gave 2:1host:chloride ratio, while the tetramer and pentamer gave 1:1complexes. The secondary structure of the oligo(amide-triazole)swas studied using NMR spectroscopy and circular dichroism. Thesestudies showed that the larger host molecules (tetramer andpentamer) adopted a stabilized U-turn and were able to bind just onechloride anion. Only the pentamer displayed a helical conformation,which was slightly distorted in the presence of chloride salts.Interestingly, chloride binding involves not only the triazole-CH butalso H atoms from the carbohydrate moieties. These compoundscould be applied for chloride sensing by ESI-MS.