A capsule-like molecule was constructed by dimerization of pyridine-containing homooxacalixaryl esters utilizing a PdII-pyridine interaction when Li+ ions were bound to the ionophoric lower rims. 1H NMR spectral studies showed that the self-assembled molecular capsule 3b·(Li+)2 has a highly symmetrical D3h-structure. It was also found that this self-assembled molecular system can form capsular structures in the presence of Na+ or ammonium (R*NH3+) ions. Very interestingly, these molecular capsules are twisted into triply bridged helical structures, and chiral R*NH3+ guests included in the cavity induce a change in the (P) versus (M) ratio, resulting in high chiral induction (∼70%). These results indicate that the self-assembled molecular capsule 3b has a novel chiral factor in which the (P) versus (M) equilibrium is readily controllable by the inclusion of chiral guest molecules.
All Science Journal Classification (ASJC) codes
- Colloid and Surface Chemistry