The hydrocarbon in-adamantane, an adamantane isomer in which one methine hydrogen atom is inside the cage, is predicted by ab initio calculations to be isolable at dry-ice temperature. It is 440 kJ/mol less stable than ordinary adamantane but has a barrier to isomerization of about 71 kJ/mol. It appears to be stable against dimerization, moisture, and air. The inverted CH bond is compressed and has a stretching frequency about 600 cm-1 higher than usual. The interior hydrogen atom has an nmr shift more typical of aromatic compounds. The symmetrical pentadecafluoro derivative (C10F15H) is more stable than the parent hydrocarbon, with an estimated half-life of 100 years at room temperature.
Journal of the American Chemical Society
fluorocarbon, high-energy, hydrocarbon, inverted
in-Adamantane, a Small Inside-Out Molecule, Journal of the American Chemical Society
(Accessed December 6, 2023)