Anion recognition properties of pyridine-2,6-dicarboxamide and isophthalamide derivatives containing l-tryptophan moieties

Abstract

l-Tryptophan containing anion receptors 1 and 2 have shown interesting features. Receptor 1 behaves as a hetero-ditopic dicompartimental receptor for fluoride and chloride with a certain selectivity for fluoride as supported by ¹H NMR titrations and molecular modeling, while receptor 2 forms only 1:1 complexes. Moreover, receptor 1 reveals a certain affinity towards the l enantiomers of amino acids alanine and serine.

Keywords:

• anion recognition
• ditopic receptors
• enantiomeric discrimination

Notes

1. DMSO is highly solvating for hard metal ions. In particular, the solvation free energy for Na⁺ in DMSO is 13.4 kJ/mol lower than that in water ( 15 ). This should make the formation of ionic couples in DMSO less favoured.