A bis(triazole)benzamide receptor for the complexation of halide anions and neutral carboxylic acid guests. Guest-controlled topicity and self-assembly

Abstract

Bis(triazole)benzamide 1 has been readily synthesized by means of Cu-catalyzed 1,3-dipolar cycloaddition and its ability to bind halide anions and neutral gallic acid derivative 12GA has been theoretically and experimentally investigated. The cavity defined by the N–H amide group and the vicinal aromatic hydrogens is suitable to form H-bonding arrays with halide guests. The stability of complexes 1·Cl⁻ and 1·Br⁻ is very similar, as DFT calculations predict and ¹H NMR titration experiments confirm. The zigzag “anti” conformation of the molecule generates two regions with complementary positive and negative potentials that favor the statistical complexation of two molecules of the neutral carboxylic acid 12GA. This guest-controlled topicity demonstrates the versatility of this class of receptor to bind species of different nature. The amide group determines the complexation of both anionic and neutral species by primary acid–base interactions.