Enantioselective radical reactions can be induced by electron spin polarization: A quantum mechanism for Nature's emergent homochirality?

Fuente: arXiv
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Autor principal: Fay, Thomas P
Formato: Preprint
Publicado: 2025
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author Fay, Thomas P
author_facet Fay, Thomas P
contents Biomolecules that constitute life on Earth are chiral, but the precise mechanism by which homochirality emerged remains a mystery. In this work it is demonstrated that reactions of radical pairs, where one of the radical electron spins is polarised, can be enantioselective. This phenomenon arises from transient coherent quantum dynamics of the radical pair electron spins, which is known to occur even in warm and noisy condensed phase environments, where energetic perturbations much smaller than thermal energy can have large effects on reactivity. A quantitative theory is presented based on the molecular theory of chirality induced spin selectivity (CISS), where electron exchange interactions and chirality-dependent spin-orbit coupling effects control enantioselectivity. This theory provides useful bounds on the maximum enantiomeric excess for these reactions, which are found to be consistent with previous experiments. The enantioseletive radical pair mechanism presented here provides an alternative mechanistic basis to a recent proposal that spin-polarised photoelectrons from magnetite provided the initial chiral symmetry breaking necessary for the inception of homochirality in Nature, as well as suggests a new strategy for asymmetric synthesis using spin-polarised electrons.
format Preprint
id arxiv_https___arxiv_org_abs_2507_08287
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Enantioselective radical reactions can be induced by electron spin polarization: A quantum mechanism for Nature's emergent homochirality?
Fay, Thomas P
Chemical Physics
Biological Physics
Quantum Physics
Biomolecules that constitute life on Earth are chiral, but the precise mechanism by which homochirality emerged remains a mystery. In this work it is demonstrated that reactions of radical pairs, where one of the radical electron spins is polarised, can be enantioselective. This phenomenon arises from transient coherent quantum dynamics of the radical pair electron spins, which is known to occur even in warm and noisy condensed phase environments, where energetic perturbations much smaller than thermal energy can have large effects on reactivity. A quantitative theory is presented based on the molecular theory of chirality induced spin selectivity (CISS), where electron exchange interactions and chirality-dependent spin-orbit coupling effects control enantioselectivity. This theory provides useful bounds on the maximum enantiomeric excess for these reactions, which are found to be consistent with previous experiments. The enantioseletive radical pair mechanism presented here provides an alternative mechanistic basis to a recent proposal that spin-polarised photoelectrons from magnetite provided the initial chiral symmetry breaking necessary for the inception of homochirality in Nature, as well as suggests a new strategy for asymmetric synthesis using spin-polarised electrons.
title Enantioselective radical reactions can be induced by electron spin polarization: A quantum mechanism for Nature's emergent homochirality?
topic Chemical Physics
Biological Physics
Quantum Physics
url https://arxiv.org/abs/2507.08287