A novel C3v-symmetric molecular clip with tris(diamide) recognition sites on trindane platform for H2PO4? recognition

Article abstract of DOI:10.1016/j.tetlet.2018.03.055

To avoid the deprotonation events occurred in the receptor upon recognition of basic anions, a novel C_3v-symmetric anion receptor 2 with two amide groups appended in each arm was designed and synthesized by using the trindane tricarboxylic acid as tripodal molecular framework. The anion recognition ability by 2 was examined by ¹H NMR titration study in DMSO-d₆, which revealed that the addition of H₂PO₄^? guests caused substantial downfield shifts of the amide-NH protons peaks due to the formation of a host-guest complex in 1:1 binding stoichiometry with the estimated binding constant (K_a) of 244 M^?1. No noticeable binding of 2 was observed with other tested anions such as F^?, Cl^?, Br^?, I^?, NO₃^? and HSO₄^? under similar conditions.