Year: 2026
Type: preprint
Abstract: Converting a transition state (TS) into a minimum is a challenging, yet possible, task, commonly achievable via chemical substitution. Pressure is expected to favor TSs that correspond to volume minima, yet experimentally or computationally demonstrated TS-to-minimum conversions remain rare. Here, we demonstrate a pressure-induced TS-to-minimum conversion in the Cope rearrangement at ∼18 GPa. Extreme pressure polarizable continuum model (XP-PCM) optimizations and vibrational analyses reveal the gradual conversion of the TS imaginary mode into a real vibrational mode. Helium compression chamber (HeCC) simulations unveil a pressure-driven inversion of the reaction-path curvature at the TS in the Gibbs free energy profile. Cyano substitution produces effects on bond distances and vibrational frequencies similar to those induced by pressure, highlighting parallels between chemical and mechanical stabilization. Although compression also accelarates the open-shell pathway, the closed-shell pathway remains thermodynamically favored up to 31 GPa. These findings highlight pressure as a powerful means of reshaping reaction landscapes, effectively enabling new chemistry.
Source: ChemRxiv
Authors: Jorge Laranjeira, Roberto Cammi, Bo Chen
Language: English
Subfield: Physical and Theoretical Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
Award: G8077516668
OpenAlex ID: W7222036946