An ESR study on Jahn-Teller effect in corannulene monoanion

Solution ESR spectra of alkali-metal-doped corannulene monoanion, C20H10- h ave been observed from RT to 183 K. Eleven peaks have been observed from RT to 273 K. As the decrease of temperature, the 11 signals due to ten equiva lent protons split into complicated ones. This behavior has been interprete d in terms of pseudorotation about the C-5v. Jahn-Teller crossing. The pote ntial barriers between five equivalent C-s wells originating from the fifth -order anharmonic term have been estimated to be ca. 2.2 x 10(-3) eV. (C) 2 000 Elsevier Science B.V. All rights reserved.