| Abstract
| - A study of the kinetic stabilities of hydrogen-bonded double, tetra-, and hexarosette assemblies,comprising 36, 72, and 108 hydrogen bonds, respectively, is described. The kinetic stabilities aremeasured using both chiral amplification and racemization experiments. The chiral amplificationstudies show that solvent polarity and temperature strongly affect the kinetic stabilities of thesehydrogen-bonded assemblies. For example, the activation energy for the dissociation of atetramelamine from a tetrarosette assembly, a process that involves the breakage of 24 hydrogenbonds, was determined at 98.7 ± 16.6 kJ mol-1 in chloroform and 172.8 ± 11.3 kJ mol-1 in benzene.Moreover, racemization studies with enantiomerically enriched assemblies reveal a strongdependence of the kinetic stability on the number and strength of the hydrogen bonds involved inassembly formation. The half-lives for double, tetra-, and hexarosette assemblies were found to be8.4 min, 5.5 h, and 150 h in chloroform at 50 °C, respectively. For higher generations of thesetypes of assemblies, the kinetic stabilities become so high that they can no longer measured in adirect manner.
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