Two achiral metal-organic colloidal systems, Zn-L1 and Zn-L2, were synthesized from simple hydrazide-based ligands and zinc ions. Despite their achiral molecular components, both colloids exhibited pronounced circularly polarized luminescence (CPL) when subjected to vortex stirring in a magnetic field. The CPL signals were observed only under dynamic conditions—specifically during stirring—and vanished when the system returned to rest. This behavior indicates that the chiroptical response is not intrinsic but dynamically induced by the physical forces generated in the vortex. The dissymmetry factor (glum) reached values of –0.05 for Zn-L1 and +0.03 for Zn-L2 at specific emission wavelengths, demonstrating significant chiral light emission with tunable handedness.
The origin of this phenomenon lies in the anisotropic nanostructure of the colloids. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) revealed long, flexible nanofibers with diameters on the order of several nanometers. These fibers are capable of aligning directionally under shear forces generated by vortex stirring. In such conditions, the alignment induces macroscopic chiral anisotropy, enabling the selective emission of left- or right-handed circularly polarized light depending on the rotation direction. When stirred clockwise (CW), one enantiomeric state dominates; counter-clockwise (CCW) stirring produces the opposite. This switchability offers precise control over the chirality of emitted light without chemical modification.
Further investigation confirmed that the chiroptical properties arise from the dynamic orientation of the nanofibers rather than static structural chirality. Linear dichroism (LD) measurements showed strong polarization-dependent absorption only under stirring, confirming the ordered arrangement of the fibrous assemblies.MYH9 Antibody Formula The CD spectra displayed clear Cotton effects only during vortex stirring, reinforcing the link between motion-induced organization and optical activity.PVRL1 Antibody MedChemExpress
Notably, the host–guest interaction within these colloids enables the transfer of chiroptical properties to non-chiral fluorescent guests.PMID:35234828 Rhodamine 6G (Rh6G), a highly emissive dye, retained a quantum yield of 83% when incorporated into Zn-L1. Its CPL signal showed a negative glum value of –0.02 at 563 nm under CCW stirring. More strikingly, its carboxylic acid derivative, Rh-COOH, exhibited enhanced CPL performance with a glum of –0.046 at 570 nm, indicating stronger coupling through coordination bonding with the Zn(II) centers. Esterification of the COOH group to COOMe weakened the interaction and reduced the glum value, proving that coordination plays a critical role in enhancing chiroptical efficiency.
This study demonstrates a novel strategy for achieving high-performance CPL materials using achiral building blocks. By leveraging vortex stirring as a physical chiral inducer, it becomes possible to generate tunable, switchable, and reversible CPL without requiring pre-formed chiral moieties. The combination of stable fluorescence, high quantum yields, and controllable glum values makes these systems promising candidates for applications in secure optical communication, advanced displays, and chiral sensing technologies. Moreover, the ability to modulate CPL through external physical stimuli opens new avenues for smart functional materials.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com