Self‐Assembly of 1D Helical Nanostructures into Higher Order Chiral Nanostructures in Supramolecular Systems

Abstract

Chirality and hierarchy are two important aspects of biological systems. Investigation of the hierarchical self‐assembly of chiral supramolecular nanostructures leads not only to biomimics but also provides deep understanding of the self‐assembly and function in biological systems. While it is generally well‐known how small molecules can self‐assemble into nanostructures like chiral nanofibers, nanobelts, nanotubes and nanotwists, it is still less frequently investigated how these nanostructures can be further assembled into higher ordered chiral nanostructures. In this review, we mainly focus on how these 1D helical nanostructure can be further assembled into higher ordered or complex chiral nano/microstructures such as nanospirals, super‐nanohelices, helical nanotubes, nanoflowers, toroids, microflowers, microtubular flowers and dendritic chiral nanotwists. Moreover, some applications including asymmetric catalysis, cell adhesion, chiral optics and chiral recognition based on these nanostructures are discussed.

Chiral Polyaniline Hollow Nanotwists toward Efficient Enantioselective Separation of Amino Acids

“…Inspired by these biological structures, a variety of artificial chiral structures of functional materials have been designed and created with good electrical, optical, or magnetic properties in recent years. − As one of the most intensively investigated functional synthetic materials, conducting polyaniline (PANI) with chiral nanostructures shows potential applications in chiral sensing, chiral catalysis, enantioselective separation, and chiral electronic devices. , PANI chiral nanostructures have been prepared by the chemical oxidation of aniline monomer in an acidic aqueous solution using a strong oxidant of ammonium peroxydisulfate (APS) when induced by chiral doping acids − or helical proteins templates. , Nevertheless, most of the man-made chiral nanostructures are helical or twisted nanobelts/nanofibers. Compared with these familiar chiral nanostructures, complex chiral nanostructures (such as hollow twists or helixes) are more significant for creating biomimetic chiral multifunctional nanomaterials or devices . However, achieving complex chiral nanostructures of functional nanomaterials is still a scientific challenge.…”

“…Compared with these familiar chiral nanostructures, complex chiral nanostructures (such as hollow twists or helixes) are more significant for creating biomimetic chiral multifunctional nanomaterials or devices. 14 However, achieving complex chiral nanostructures of functional nanomaterials is still a scientific challenge.…”

Chiral Supramolecular Self-Assembly Catalysts with Enhanced Metal Ion Interaction for Higher Enantioselectivity

“…Catalysts with high enantioselectivity play a significant role in obtaining specific enantiomers from organic asymmetric reactions and thus have been widely used in the fabrication of chiral drugs, agricultural chemicals, and functional chiral materials. − With the fast development of supramolecular chemistry, the chiral catalysts constructed from supramolecular self-assembly have attracted increasing attention due to their easier preparation process and more flexible tunability than the chiral small molecular catalysts. − The design or modification of traditional chiral small molecular catalysts is based on the method of organic synthesis, through the modification of covalent bonds, which requires higher energy input and a more complex process. − Moreover, chiral supramolecular self-assembly catalysts have the advantages of good catalytic efficiency and cyclic stability. ,, In order to achieve higher enantioselectivity, more effort has been devoted to investigating the effect of various noncovalent interactions, like hydrogen bonds, van der Waals, amphiphilic, and π–π interactions, for the building and tuning of supramolecular scaffolds themselves with chiral morphology. − However, less attention was paid to the interaction between the metal ions as catalytic centers and the supramolecular scaffolds as chiral substrates. A strategy that can effectively reinforce such metal ion–supramolecular scaffold interaction may potentially intensify the chirality transfer from the supramolecular scaffold to the metal ion and finally to the reactant molecule, achieving the enhanced catalytic enantioselectivity.…”

Three-level hierarchical self-assembly of azobenzene conjugated phenylalanines into superhelical nanostructures with light-switchable helicity

“…1 In particular, hierarchical supramolecular superhelices with a long-range ordered spatial arrangement in biological systems are impressive, where primary helices further self-assemble into more sophisticated higher order structures. 2 A classic example is the double-helical DNA where two single-stranded helices further entwine into a double helix via hydrogen bonds between base pairs, which has been proved to be related to genetic information storage and transfer. 3 Similar hierarchical superhelices are ubiquitous in biological systems, such as triple-helical collagen, 4 quadruple-helical G-quadruplexes 5 and so on.…”