Solvent Effect on the Chiral Arrangement for Two Achiral Metal-Organic Colloids in the Vortex Field: Rheological Study and Retention Study.

The vortex features a helical structure and exhibits macroscopic chirality. Over the past few decades, scientists have observed that several achiral compounds display chiroptical activity within the vortex field. The researchers believe that chiral arrangement may have occurred in this process. Herein, we investigate two achiral metal-organic colloids (ZnL/DMSO and ZnL/DMF) which have similar chemical components but exhibit distinct vortex-responsive chiroptical properties. In the vortex field, the ZnL/DMSO colloid presents chiroptical activity, whereas the ZnL/DMF colloid remains chiroptically silent. Rheological studies reveal the possible underlying reasons. The strong solvent-colloidal particles interactions in the ZnL/DMSO colloid endow the system with excellent viscoelasticity and reversible thixotropy. These characteristics enable the ZnL/DMSO colloid to form a reversible chiral arrangement within the vortex. In contrast, the ZnL/DMF colloid fails to respond to the vortex. Furthermore, the addition of the charged molecule D enhanced the rheological properties of the ZnL/DMSO colloid, with the potential to preserve its chiroptical activity. Overall, this research is expected to provide new insights into the vortex-induced chirality of supramolecular colloids, contributing to a deeper understanding of the underlying principles of chiroptical property in such systems.