A Unique Spherical Molecular Host with D2d Symmetry. A Novel Intramolecular Kinetic Equilibrium in Metal Ion Complexation between Two Crown Ethers
摘要:
[GRAPHICS]A spherical host with D-2d symmetry consisting of a tetrathia[3.3.3.3]paracyclophane and two 18-crown-6 moieties was synthesized. Its crystal structure shows a central cavity with a diameter of 1.96 Angstrom and a depth of 6.75 Angstrom. A Na+ ion could rest in the cavity center but prefers core binding to external binding in one of the crown units. An intramolecular kinetic equilibrium was reached with the Na+ ion switching between the two crown units with an energy barrier of 14.1 +/- 3 kcal/mol.
A Unique Spherical Molecular Host with D2d Symmetry. A Novel Intramolecular Kinetic Equilibrium in Metal Ion Complexation between Two Crown Ethers
摘要:
[GRAPHICS]A spherical host with D-2d symmetry consisting of a tetrathia[3.3.3.3]paracyclophane and two 18-crown-6 moieties was synthesized. Its crystal structure shows a central cavity with a diameter of 1.96 Angstrom and a depth of 6.75 Angstrom. A Na+ ion could rest in the cavity center but prefers core binding to external binding in one of the crown units. An intramolecular kinetic equilibrium was reached with the Na+ ion switching between the two crown units with an energy barrier of 14.1 +/- 3 kcal/mol.