Hydrogen-bonded encapsulation complexes in protic solvents.
We describe here the behavior of the hydrogen-bonded capsule 1.1 and its complexes in protic solvents. The kinetics and thermodynamics of the encapsulation process were determined through conventional (1)H NMR methods. The enthalpies and entropies of encapsulation are both positive, indicating a process that liberates solvent molecules. The rates of dissociation-association of the capsule were comparable to the rates for the in-out exchange of large guests, which suggests that guest exchange occurs by complete dissociation of the capsule in protic solvents. The stability of the hydrogen-bonded capsule 1.1 toward protic solvents depends strongly on the guests, with the best guest being dimethylstilbene 8. The results establish guidelines for the properties of capsules that could be accessed in water.
Amaya
Toru
T
The Skaggs Institute for Chemical Biology, Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
Rebek
Julius
J
D001555:Benzene Derivatives / Q000737:chemistry*; D002214:Capsules; D003903:Deuterium; D004988:Ethers, Cyclic / Q000737:chemistry*; D006860:Hydrogen Bonding; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D000432:Methanol / Q000737:chemistry*; D008958:Models, Molecular; D012118:Resorcinols / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics
D001555:Benzene Derivatives; D002214:Capsules; D004988:Ethers, Cyclic; D012118:Resorcinols; C442939:cavitand; C010219:mesitylene; D003903:Deuterium; D000432:Methanol