Enantiospecificity in NMR Enabled by Chirality-Induced Spin Selectivity

TL;DR

This paper presents a theoretical and computational study showing that NMR responses in chiral molecules are enantiospecific due to spin-orbit coupling, enabling chiral discrimination without external agents.

Contribution

It introduces a theoretical framework and DFT calculations demonstrating enantiospecific NMR responses in chiral molecules caused by spin-orbit coupling effects.

Findings

J-couplings depend on enantiomeric form

DFT confirms enantiospecific NMR responses

NMR can discriminate chirality without external agents

Abstract

Spin polarization in chiral molecules is a magnetic molecular response associated with electron transport and enantioselective bond polarization that occurs even in the absence of an external magnetic field. An unexpected finding by Santos and co-workers reported enantiospecific NMR responses in solid-state cross-polarization (CP) experiments, suggesting a possible additional contribution to the indirect nuclear spin-spin coupling in chiral molecules induced by bond polarization in the presence of spin-orbit coupling. Herein we provide a theoretical treatment for this phenomenon, presenting an effective spin-Hamiltonian for helical molecules like DNA and density functional theory (DFT) results on amino acids that confirm the dependence of J-couplings on the choice of enantiomer. The connection between nuclear spin dynamics and chirality could offer insights for molecular sensing and quantum information sciences. These results establish NMR as a potential tool for chiral discrimination without external agents.