Folded Propeller Chiral Structures Exclusively Adaptive to Chloroform

Chiroptical Signal Inversion of Peptido-Coassemblies in Confined Parallel-Laminar Microfluidics

Chirality plays a vital role in material properties, and precise control of chiral signals is key to designing functional materials. Supramolecular self-assembly offers an efficient means to integrate chiral building blocks with chromophores, yet controlling the assembly pathway remains challenging due to the complexity of non-covalent interactions. Here, we introduce a continuous parallel-laminar-assisted self-assembly strategy that exploits solvent ordering and solute diffusion in confined environments to regulate chiral signals in multi-component peptide co-assemblies. Notably, six nonpolar amino acids exhibit significantly enhanced chiroptical responses, as confirmed by circular dichroism (CD) and circularly polarized luminescence (CPL) spectroscopy. Intriguingly, Fmoc-Ala and 1-aminopyrene (AP) co-assemblies formed in a microfluidic chip show a reversed chiroptical signal compared to those from batch reactions. Molecular dynamics (MD) simulations and COMSOL modeling suggest that velocity gradients and shear forces in microfluidics induce ordered non-covalent interactions, altering excimer stacking and modulating chiroptical properties. This study presents an effective strategy for controlling chiral optical signals in confined environments, offering an interesting approach for supramolecular chiral transfer and regulation.

Hydrogen Bonded Foldamers with Axial Chirality: Chiroptical Properties and Applications

Folding phenomenon refers to the formation of a specific conformation widely featured by the intramolecular interactions, which broadly exist in biomacromolecules, and are closely related to their structures and functions. A variety of oligomeric folded molecules have been designed and synthesized, namely "foldamer", exhibiting potentials in pharmaceutical and catalysis. Molecular folding is a promising strategy to transfer chirality from substituents to the whole skeleton, when chirality transfer, amplification, evolution, and other behaviors could be achieved. Investigating chirality using foldamer model deepens the understanding of the structure-function correlation in biomacromolecules and expands the molecular toolbox towards chiroptical and asymmetrical chemistry. Substitutes with abundant hydrogen bonding sites conjugated to a rotatable aryl group afford a parallel β-sheet-like conformation, which enables the emergence and manipulation of axial chirality. This concept aims to give a brief introduction and summary of the hydrogen bonded foldamers with anchored axial chirality, by taking some recent cases as examples. Design principles, control over axial chirality and applications are also reviewed.