Magnetic Circular Dichroism Elucidates Molecular Interactions in Aggregated Chiral Organic Materials

Angew Chem Int Ed Engl. 2024 Jan 2;63(1):e202313315. doi: 10.1002/anie.202313315. Epub 2023 Nov 29.

Abstract

Chiral materials formed by aggregated organic compounds play a fundamental role in chiral optoelectronics, photonics and spintronics. Nonetheless, a precise understanding of the molecular interactions involved remains an open problem. Here we introduce magnetic circular dichroism (MCD) as a new tool to elucidate molecular interactions and structural parameters of a supramolecular system. A detailed analysis of MCD together with electronic circular dichroism spectra combined to ab initio calculations unveils essential information on the geometry and energy levels of a self-assembled thin film made of a carbazole di-bithiophene chiral molecule. This approach can be extended to a generality of chiral organic materials and can help rationalizing the fundamental interactions leading to supramolecular order. This in turn could enable a better understanding of structure-property relationships, resulting in a more efficient material design.

Keywords: Chirality; Exciton Interactions; Magnetic Circular Dichroism; Self-Assembly; Thin Films.