Ludwig Boltzmann and the Norbornyl Cation

Article abstract of DOI:10.1021/j100353a057

The norbornyl cation is a fluxional species capable of rearranging to as many as 7!*11! degenerate configurations.The process has an associated entropy, depending on how many distinguishable structures are attainable under experimental conditions and this markedly effects the position of hydride-transfer equilibria observable in solution.The equilibration of norbornane with the tert-butyl cation has been observed to be endothermic by 9.6 kcal/mol and be driven toward the formation of the fluxional ion by an entropy change of 34.4 gibbs/mol in the 50-deg span from 193 to 243 K.