Synthesis and Inclusion Properties ofC3-Symmetrically Capped Hexahomotrioxacalix[3]arenes with Ester Groups on the Lower Rim

Abstract

A triply bridged capped hexahomotrioxacalix[3]arene 4 with C3-symmetry was synthesized by treatment of hexahomotrioxacalix[3]arene tricarboxylic acid 3 with 1,3,5-tris(bromomethyl)benzene in the presence of Na2CO3 in DMF. The complexation modes of 4 with cations differed according to the ionic size and properties of the guest cations, as was clearly elucidated by 1H NMR titration spectra. Conformational studies on 4 in solution and in the solid state are also described.