Affiliation:
1. Department of Chemistry and Research Institute of Natural Science Gyeongsang National University Jinju 52828 Korea
2. Department of Chemistry and Chemical Engineering Inha University Incheon 22212 Korea
Abstract
AbstractTripyrromethane‐based tripodal compounds 1–3 were synthesized as anion receptors. It was revealed by 1H NMR spectroscopic analyses carried out in CDCl3 that tripyrromethane 1 with an ester group was capable of recognizing F−, Cl−, Br−, and H2PO4− with relatively high selectivity for F−. By contrast, receptor 2 having an additional hydrogen bond donor of an amide group binds F− and H2PO4− with much improved affinity relative to receptor 1. On the other hand, receptor 3 bearing formyl groups on its two pyrrole subunits showed markedly enhanced selectivity for F− presumably due to the increased acidity of the pyrrolic NHs and the resulting strengthened intermolecular hydrogen bonds. In addition, tripodal receptors 1–3 were found to bind H2PO4−, a tetrahedral oxyanion, more efficiently than 2‐dimensional macrocyclic calix[4]pyrrole 4.