Acyclic Cucurbit[]uril-Type Receptors: Optimization of Electrostatic Interactions for Dicationic Guests.

The synthesis of acyclic CB[]-type host () is reported. By optimizing the placement of the sulfate groups nearby the electrostatically negative ureidyl C═O portals, the binding affinity of this class of receptors toward hydrophobic (di)ammonium guest molecules (-) is maximized. The X-ray crystal structures of and · are reported.

Triptycene Walled Glycoluril Trimer: Synthesis and Recognition Properties.

We report the synthesis of a new acyclic CB[n]-type host (1) that features a central glycoluril trimer capped by triptycene sidewalls. Host 1 has good solubility in water (≈ 3 mM) and does not undergo strong self-association (K = 480 M). We probed the geometry of the complexes by analyzing the complexation induced changes in the H NMR spectra and measured the complexation thermodynamics by isothermal titration calorimetry.