Cyclopropenyl Anions: Carbon Tunneling or Diradical Formation? A Contest between Jahn-Teller and Hund

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


The π bond shifting (automerization) by carbon tunneling of cyclopropenyl anions was computationally analyzed by the small curvature tunneling methodology. Similar to other antiaromatic cases, the process is hindered by substituents departing from planarity, since these groups must be realigned along with the π bond shifting. With hydrogens as substituents the tunneling is extremely fast, in a case of both heavy and light atom tunneling. But, with more massive substituents (such as Me and F), and especially with longer groups (such as CN), the tunneling probability is reduced or even virtually canceled. The automerization of triphenylcyclopropyl anion by tunneling was supposed to be impossible due to the high mass of the phenyl groups. However, it was found that the ground state of this species is actually a D3h aromatic triplet, a single-well system that cannot undergo automerization. For this and other systems with π acceptor groups, the superposition of states that generates the second-order Jahn-Teller distortion is diminished, and by Hund's rule, the triplet results in the ground state.

Original languageEnglish
Pages (from-to)3089-3095
Number of pages7
JournalJournal of Chemical Theory and Computation
Issue number7
StatePublished - 2 Jun 2015

ASJC Scopus subject areas

  • Computer Science Applications
  • Physical and Theoretical Chemistry


Dive into the research topics of 'Cyclopropenyl Anions: Carbon Tunneling or Diradical Formation? A Contest between Jahn-Teller and Hund'. Together they form a unique fingerprint.

Cite this