# Enantioselective Magneto-Chiral Photochemistry Rediscovered

## TL;DR

Scientists rediscovered a method using light and magnetic fields to create a slight preference for one molecular handedness over another, which could relate to how life's molecules became one-handed.

## Contribution

The study experimentally rediscovered enantioselective magneto-chiral photochemistry and quantified its enantiomeric excess.

## Key findings

- An enantiomeric excess of 0.50% was achieved using magneto-chiral photochemistry.
- Circularly polarized photochemistry produced a lower enantiomeric excess under the same conditions.
- The effect was observed using potassium tris(oxalato)chromate(III) at specific wavelengths and magnetic fields.

## Abstract

Enantioselective magneto-chiral photochemistry (MChPh),
which represents
the ability of an unpolarized light beam
k
applied along a magnetic field
B
to
produce an enantiomeric excess (ee), was experimentally
demonstrated for the first time 25 years ago. Despite the relevance
that this effect can have for the origin of molecular homochirality,
no other experiment has been reported in the literature since then.
With the aim of reexploring this enantioselective photochemical reactivity
and quantitatively determining the ee achievable
through MChPh as a function of the applied magnetic field and the
laser irradiation wavelength, we report here on new magneto-chiral
dichroism (MChD) studies and MChPh experiments on potassium tris­(oxalato)­chromate­(III).
By irradiating a racemic mixture of enantiomers in solution (T = 5 °C) at λ = 695.5 nm (500 mW), the wavelength
where MChD is maximum, under a magnetic field
B
= 30 T for 30 min, an ee of 0.50% has
been obtained. We demonstrate that under the same experimental conditions,
circularly polarized photochemistry (CPPh), the most accredited mechanism
at the origin of molecular homochirality, yields a lower ee.