Synthesis and Anion Recognition Features of a Molecular Cage Containing Both Hydrogen Bond Donors and Acceptors.

A molecular cage, macrobicycle 2, containing amide and pyrrole groups as hydrogen-bonding donors and imine groups as hydrogen-bonding acceptors has been synthesized. Compound 2 was found to recognize tetrahedral oxyanions with high affinities, such as H2PO4-, HSO4-, SO42-, and HP2O73-, as well as the spherical halide anions, in chloroform. A single-crystal X-ray diffraction analysis revealed that compound 2 formed a 1:1 complex with H2PO4- in the solid state.