MasterNanosciences, nanotechnologies

Life homochirality consists in the exclusive production and use of homochiral molecular building blocks (L-amino acids and D-sugars) for the fabrication of biological polymers. Why homochirality has prevailed over a combination of left- and right-handed molecules and which symmetry breaking process is at the origin of homochirality in the molecules of life remain among one of the greatest unsolved questions in science. Various chemical, physical and physico-chemical initiating mechanisms have been proposed, but the experimental demonstrations reported so far are only partially convincing. Magneto-Chiral Dichroism (MChD), the enantioselective absorption of unpolarized light that chiral systems experience under magnetic fields, and the spontaneous enantiomeric enrichments generated in photochemical reactions performed under magnetic fields (Magneto-Chiral Photochemistry) have been proposed as potential mechanisms for the emergence of molecular homochirality. Thorough experimental investigations on this regard are still missing. Within this internship, original physico-chemical experiments under magnetic fields will be performed using in-house built set-up to explore Magneto-Chiral Photochemistry as a potential mechanism at the basis of molecular homochirality.

Related publications

Rikken, G. L. J. A.; Raupach, E. Observation of Magneto-Chiral Dichroism. Nature 1997, 390, 493.
Rikken, G. L. J. A.; Raupach, E. Enantioselective Magneto-Chiral Photochemistry. Nature 2000, 405, 932
Atzori, M.; Rikken, G. L. J. A.; Train, C. Magneto‐Chiral Dichroism: A Playground for Molecular Chemists. Chem. –
A Eur. J. 2020, 26, 9784.
Raju, M. S. ; Train, C. ; Rikken, G. L. J. A. ; Atzori, M. Magneto-Chiral Photochemistry Rediscovered, 2023, Manuscript in Preparation.

Program and expected skills

 Programs:   M1 Nanochemistry - M1 Soft Matter and Biophysics - Phelma Biomedical Engineering

This subject has a strong multidiscipinary character and requires to work at the interface between different fields.  It will include the preparation of simple tris-chelated transition metal complexes that will be characterized by a multi-technique approach (various electronic spectroscopies, magnetometry, and advanced magneto-chiral dichroism measurements), while the biologically relevant molecules will be obtained from commercial sources.  Once the systems fully characterized, photochemistry experiments with lasers irradiation under magnetic fields will be performed using set-ups under constant development to generate enantiomeric excess with unpolarized light sources. The same experiments will be conducted without magnetic field using circularly polarized light. The results of the photochemistry experiments will be correlated to the spectroscopic findings.