Photoelectron Circular Dichroism as a Signature of Subtle Conformational Changes: The Case of Ring Inversion in 1-Indanol.

Chirality plays a fundamental role in the molecular recognition processes. Molecular flexibility is also crucial in molecular recognition, allowing the interacting molecules to adjust their structures and hence optimize the interaction. Methods probing simultaneously chirality and molecular conformation are therefore crucially needed. Taking advantage of a possible control in the gas phase of the conformational distribution between the equatorial and axial conformers resulting from a ring inversion in jet-cooled 1-indanol, we demonstrate here the sensitivity of valence-shell photoelectron circular dichroism (PECD) to both chirality and subtle conformational changes, in a case where the photoelectron spectra of the two conformers are identical. For the highest occupied orbital, we observe a dramatic inversion of the PECD-induced photoelectron asymmetries, while the photoionization cross-section and usual anisotropy (β) parameter are completely insensitive to conformational isomerism. Such a sensitivity is a major asset for the ongoing developments of PECD-based techniques as a sensitive chiral (bio)chemical analytical tool in the gas phase.