Intramolecular binding site organization by Pd(II) complexation with a resorcin[4]arene derivative

Intramolecular assembly of a binding site by Pd(II) ion complexation with a resorcin[4]arene derivative has led to a water-soluble resorcin[4]arene receptor. The bowl-shaped cavitand host 2 shows a good binding affinity to aromatic carboxylates with alkyl moiety of an appropriate length in D2O. The guest inclusion within the host cavity was confirmed by 1H NMR spectroscopy. Hydrophobic and electrostatic interactions turned out to act as cooperative binding force for a strong complex formation with appropriate anionic guests in water.