Synthesis and anion recognition properties of pyrrole-bearing acyclic receptors

A new series of acyclic anion receptors (1–4) based on methyl 5-(aminomethyl)-1H-pyrrole-2-carboxylate were designed and synthesized. The anion recognition properties of these receptors were examined by 1H NMR spectroscopy and rationalized by density functional theoretical calculation. Receptor 1 displays the highest affinity and selectivity for anionic guests mainly due to the intramolecular hydrogen bonds and rigid molecular geometry.