Macroscopic Chirality of Supramolecular Gels Formed from Achiral Tris(ethyl cinnamate) Benzene‐1,3,5‐tricarboxamides

Abstract

A C3‐symmetric benzene‐1,3,5‐tricarboxamide substituted with ethyl cinnamate was found to self‐assemble into supramolecular gels with macroscopic chirality in a DMF/H2O mixture. The achiral compound simultaneously formed left‐ and right‐handed twists in an unequal number, thus resulting in the macroscopic chirality of the gels without any chiral additives. Furthermore, ester–amide exchange reactions with chiral amines enabled the control of both the handedness of the twists and the macroscopic chirality of the gels, depending on the structures of the chiral amines. These results provide new prospects for understanding and regulating symmetry breaking in assemblies of supramolecular gels formed from achiral molecular building blocks.

Supramolecular Chirality in Self-Assembled Systems

“…Importantly, the overcrowded stacking of the cinnamate rings within the assembly plays a very important role in the spontaneous symmetry breaking and production of an uneven number of helical nanostructures with different handedness. 284 Furthermore, this phenomenon may generally occur in the gel systems of BTA derivatives. It is expected that many of the other BTA derivatives will show similar properties.…”

Control over the emerging chirality in supramolecular gels and solutions by chiral microvortices in milliseconds

“…1 ). Two kinds of achiral molecules, (tris(ethyl cinnamate) benzene-1,3,5-tricarboxamide, BTAC 6 , and tetra-(4-sulfonatophenyl) porphyrin), TPPS 4 13 , which have been reported to exhibit symmetry breaking during gel formation or aggregation, are selected. We first investigate the flow-induced self-assembly of BTAC (Fig.…”

“…Moreover, the enantiospecific reversible effect on J-aggregates in dynamic stirring conditions is reversible, due to the temporary chiral ordering of nanoparticles in the flows 33 , 34 . In contrast to the flow-driven chirality in solutions, stirring during gelation fails to affect the supramolecular chirality in gels, which has been determined stochastically by initial spontaneous symmetry breaking 6 . On the basis of these contradictory observations, it remains an enigma how an efficient hydrodynamic force could be created and how it controls over the supramolecular chirality during the self-assembly process.…”

Generation of twisted nanowires with achiral organic amphiphilic copper complexes

“…As mentioned in the introduction, lipid-layer arrangement twisted into chiral structures were observed. 11,12 Both investigated amphiphilic complexes should also be able to form lipidlayer-like structures. 20 Lipid layers with tilted molecular arrangement were discussed to play a crucial role in symmetry breaking towards assembly of chiral laments.…”

“…[7][8][9] This unusual behavior was ascribed to a chiral symmetry-breaking mechanism during phase transitions. 9,10 More examples where macroscopic chirality was detected in non-chiral compounds included a C3-symmetric benzene-1,3,5-tricarboxamide, 11 which was substituted with ethyl cinnamate, spin casted dendritic zinc porphyrins, 12 achiral bent core molecules, 13 and Langmuir-Blodgett lms of calcium arachidate. 14 In lyotropic and thermotropic phases of amphiphiles, a reduction of water content or temperature could induce a phase transition from a uent, liquid crystalline La phase to a at gel Lb phase, where the lipids were organized cooperatively.…”