Four macrotricyclic cage hosts which feature four positive binding sites oriented toward the center of the intramolecular cavity are presented as promising candidates for anion receptors and they have been expected to play a important role in the selective encapsulation of the halide ion Cl- or Br . The complementarity between a macrotricyclic quaternary ammonium ion and Cl- was achieved by fine-tuning of the four ammonium nitrogen atoms and the endocyclic methylene groups. The cage hosts [R4N4(C5H10)4(C6H12)2]4+ (abbreviated as [556]) showed perfect encapsulation of all chloride ions in acetonitrile at 0 < r= ([Cl-]o/[[556]]o) < or = 1 within the sensitivity of the 1H NMR spectra in combination with a rather slow chemical exchange of the Cl- ion in an encapsulation/decapsulation equilibrium with [556]. Further, the selective encapsulation of all the chloride ions into [556] cage occurs unambiguously at r = 1 in the presence of equimolar amounts of Br-. The structural complementarity of the newly designed [556] host prevails over the Hofmeister-series restraints determined by differences in Gibbs free energy of halide anion solvation.

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The cage receptor [R4N4(C5H10)2(C6H12)4]4+ ([566]RMQA4+) was designed and synthesized. X-ray crystallography, 1H-NMR and molecular mechanics calculation revealed the complexibility and selectivity toward Br−. In the presence of both Cl− and Br−, [566]RMQA4+ shows the higher selectivity toward Br− in aqueous solution.

The crystal structure and molecular recognition behaviour of a new chiral-amino cyclodextrin are reported; van der Waals interaction, hydrogen bond and the electrostatic interactions play an important role in the self-assembling process and chiral recognition for (R)-(--)-and (S)-( + )-mandelic acid.

Three-dimensional hydrogen-bonding networks have been found in the crystal structure of the Cu II complex of the semi-N,O-bidentate Schiff base L 14 , having both hydrogen donor and acceptor sites. The infinite one-dimensional channels and cavities and the helical structure are presented as a result of the complementary intermolecular hydrogen-bonding interaction (᎐SO 2 ؒ ؒ ؒ H 2 N᎐). Molecular mechanics calculations show the difference between calculated and X-ray structures of the Cu II ᎐L 14 complex.