Enhanced diastereocontrol via strong light-matter interactions in an optical cavity

TL;DR

This paper demonstrates through computational methods that strong light-matter interactions in an optical cavity can significantly control the diastereomeric excess in chiral molecule photoisomerization, enabling orientation-based selectivity without altering molecular chirality.

Contribution

It introduces a cavity QED generalization of time-dependent density functional theory to show how optical cavities influence diastereoselectivity in chiral molecule reactions.

Findings

Cavity interactions can increase diastereomeric excess from 17% to 40%.

Orientation of cavity mode polarization affects diastereoselectivity.

Cavity-induced changes to molecular orbitals drive the observed effects.

Abstract

The enantiopurification of racemic mixtures of chiral molecules is important for a range of applications. Recent work has shown that chiral group-directed photoisomerization is a promising approach to enantioenrich racemic mixtures of BINOL, but increased control of the diasteriomeric excess (de) is necessary for its broad utility. Here we develop a cavity quantum electrodynamics (QED) generalization of time-dependent density functional theory and demonstrate computationally that strong light-matter coupling can alter the de of chiral group-directed photoisomerization of BINOL. The relative orientation of the cavity mode polarization and the molecules in the cavity dictates the nature of the cavity interactions, which either enhance the de of the (R)-BINOL diasteriomer (from 17% to $\approx$ 40%) or invert the favorability to the (S)-BINOL derivative (to $\approx$ 34% de). The latter outcome is particularly remarkable because it indicates that the preference in diasteriomer can be influenced via orientational control, without changing the chirality of the directing group. We demonstrate that the observed effect stems from cavity-induced changes to the Kohn-Sham orbitals of the ground state.