External Electric Fields Interrupt the Concerted Cope Rearrangement of Semibullvalene

The topic of this paper is whether the mechanism of the degenerate Cope rearrangement of semibullvalene can be affected by the presence of electrostatic fields. Herein, we report that the shape of the energy surface, as demonstrated by an interrupted (stepwise) mechanism, is altered in the presence of a copper cation, Cu+. Natural bond-orbital and block-localized wave-function energy decomposition analyses suggest that orbital and electrostatic interactions play a major role in altering the shape of the energy surface. Applying additional external electric fields (EEFs) induces a significant change to the energy surface with Cu+ present but negligible effects in the absence of Cu+. These findings are consistent with recent studies that demonstrate that EEFs more readily stabilize/destabilize systems with larger, more polarizable, dipole moments.

Automated summary

The presence of a copper cation, Cu+, alters the shape of the energy surface in the degenerate Cope rearrangement of semibullvalene. Orbital and electrostatic interactions play a major role in this alteration, with additional external electric fields inducing significant changes in the energy surface. This study is consistent with recent findings that EEFs more readily stabilize/destabilize systems with larger, more polarizable, dipole moments.