Synthesis and Recognition Properties of Enantiomerically Pure Acyclic Cucurbit[n]uril-Type Molecular Containers

Enantiomerically pure acyclic cucurbit­[n]­uril containers 1 and 2 were synthesized by the condensation of enantiomerically pure aromatic sidewalls 3b and 4b with glycoluril tetramer 5. Containers 1 and 2 are C₂-symmetric, feature four arms of the same handedness, and bind to a variety of guests (6–15) in aqueous solution including aliphatic and aromatic ammonium ions, amino acids, dyes, and viologens. The binding constants of hosts 1_Ac and 1_OH toward selected chiral ammonium ions were measured by ¹H NMR and UV/vis spectroscopy.