1-ADAMANTYL AND 2-ADAMANTYL RADICALS AND CATIONS IN THE GAS-PHASE - THERMOCHEMISTRY AND MASS-SPECTROMETRY

The heats of formation of the 1- and 2-adamantyl cations and of the l- adamantyl radical have been measured directly by electron impact appea rance energies. The values are Delta(f)H(o)[1-adamantyl(+)] = 152 +/- 3 kcal mol(-1), Delta(f)H(o)[2-adamantyl(+)] = 171 +/- 3 kcal mol(-1) and Delta(f)H(o)[1-adamantyl'] = 12 +/- 3 kcal mol(-1). The results al so lead to a value of 16 kcal mol(-1) for the heat of formation of the 2-adamantyl radical. Collision-induced dissociation mass spectra of t he 1- and 2-adamantyl cations allow low internal energy ions to be dis tinguished. However, it is shown that at higher internal energies the two ions share a common potential energy surface. This is supported by the statistical mixing of all hydrogen and deuterium atoms, prior to the lowest energy dissociation channel, in the 1-adamantyl-3d(1)(+) is otopomer.