Institute of Solid State Physics


SS23WS23SS24WS24SS25      Guidelines for Master Students

From Achiral Beginnings to Chiral Innovations: Symmetry Breaking in Chiral Crystals
Anmol Andotra
Institute of Solid State Physics
https://tugraz.webex.com/tugraz/j.php?MTID=mda475bc81918903250bf9f78da7a9f67
11:15 - 12:15 Wednesday 11 December 2024 

Chirality has become increasingly significant across a spectrum of disciplines, such as chemistry, materials science, biology, and the pharmaceutical industry1. Chiral crystals have garnered significant attention due to their potential applications in enantioselective catalysis, chiral sensing devices, and as fundamental components for innovative functional materials. The study of chiral symmetry breaking in molecular crystals presents an engaging interdisciplinary research area2. Under non-equilibrium conditions, the symmetric state becomes unstable and the spontaneous emergence of a non-zero enantiomeric excess arises from an achiral state through a chiral symmetry breaking transition3. This study focuses on a series of achiral X-oxoamide molecules that crystallize as chiral crystals, exhibiting an uncommon similarity in their crystal structure. Utilizing UV light, we can freeze the chirality in the solid-state and fix the stereo genic centres into a preferred configuration, which enables the separation of enantiomers. This transition from the supramolecular chirality to molecular chirality is significant, as it enhances the ability to control and manipulate chiral properties of materials at a molecular level. Characterization techniques such as X-ray diffraction, HPLC, spectroscopy, and computational modelling are employed to investigate chiral symmetry breaking. These methods offer insights into the three-dimensional arrangement of molecules within the crystal lattice, elucidating the origins of chirality and the critical intermolecular interactions, including hydrogen bonding, van der Waals forces, and electrostatic interactions. These interactions play a pivotal role in the stability and properties of molecular crystals. Anomalous scattering will be employed to determine the absolute configuration of molecular crystals and thin films, offering a novel approach in chirality and X-ray crystallography.4 This method helps reveal the relationship between molecular structure, intermolecular interactions, and crystal symmetry, facilitating the design of advanced materials with tailored chiral properties.


References:

1. Dutta, S.; Gellman, A. J., Chem. Soc. Rev., (2017),7787–7839.
2. An, G.; Yan, P.; Sun, J.; Li, Y.; Yao, X.; Li, G., CrystEngComm. (2015),4421–4433.
3. Sakamoto, M., J. Photochem.Rev., (2006),83–196.
4. Watkin, D. J.; Cooper, R. I., Chemistry (2020),796–804.