Program Details

Professor Kushal Bagchi
Rice University
Time: 11:05 a.m.

Liquid crystals as templates for crystal growth

Liquid crystals are soft materials that combine the fluidity of liquids with the structural anisotropy of crystals. We show that small molecule, columnar liquid crystals can undergo displacive, order-preserving transitions into crystalline states. Because liquid crystals can be readily organized over macroscopic length scales, transferring this orientational order into the crystal offers a new strategy for producing highly aligned organic semiconductor crystals. Such biaxial alignment is particularly important for achieving efficient and directionally controlled charge transport in electronic devices. We further demonstrate that order-preserving liquid crystal to solid transitions in aggregation-induced emitters can generate bright, polarized luminescence at room temperature. Together, these results establish liquid crystalline phases as versatile precursors for creating functionally anisotropic molecular solids.

Dr. Susanna Bertuletti
AMOLF
Time: 11:45 a.m.

Lightning-speed deracemizations via metastable phases

Obtaining enantiomerically pure compounds remains a major challenge, as traditional synthetic methods often yield racemic mixtures. In 2005, Viedma demonstrated that grinding could spontaneously deracemize sodium chlorate, a racemizable conglomerate, an approach later extended to organic molecules, including API intermediates. Crystallization-induced deracemization of racemic conglomerates has since emerged as a powerful method for complete chiral symmetry breaking. While early experiments required up to a month to achieve enantiopurity, subsequent optimization reduced deracemization times to hours, enabling industrial-scale synthesis of chiral building blocks. Here, we introduce an approach that accelerates this process dramatically, converting a nearly racemic solid phase into an enantiopure one within only 5 minutes, with enantiomeric excesses up to 97.5%. We investigate the mechanism underlying this remarkably rapid conversion and discuss its implications for the development and application of fast deracemization strategies.

Professor Nathalie Katsonis
University of Groningen
Time: 12:15 p.m.

Chirality puts molecular switches to work at the scale of cells

Artificial molecular switches and motors perform sophisticated motion at the nanoscale, but turning this motion into work at larger scales requires collective organization. Living cells achieve this through chirality: helical flagella and rotating filopodia translate molecular activity into propulsion and force. In this talk, I will show that chirality can play the same role in synthetic systems. Under visible light, chiral liquid-crystal droplets grow helical, cell-like protrusions tens of micrometers long, driven by the intercalation of an azobenzene amphiphile at the droplet interface. Molecular chirality selects the handedness of these protrusions, and droplet size sets their number. The protrusions capture, push and pull microscopic particles, and rotate attached particles against piconewton-scale forces. Under ultraviolet light, the droplets return to their spherical shape. These results establish chirality as a design principle for converting molecular switching into mechanical work at the scale of cells.