JAHN-TELLER EFFECT IN CORANNULENE ANION

摘要

Jahn-Teller effect in corannulene monoanion is investigated by means of solution ESR. The Jahn-Teller distortion from the C_(5υ) configuration to the C_s makes the ten hydrogen atoms inequivalent. ESR spectroscopy of the alkali-metal-doped monoanion solutions shows that as the temperature decreases, the eleven signals split into more complicated patterns. This can be interpreted in terms of pseudorotation about the C_(5υ) Jahn-Teller crossing. Fifth-order anharmonicity of the vibration causes five equivalent C_s wells in the adiabatic potential surface. The energy barriers among the wells were estimated to be 2.2 meV, from the temperature dependence of the spectra.