258. Supramolecular “sergeants”: in situ and multi-level induction of chirality in helical assemblies of triarylamine trisamide monomers
     Antoine Perennes, Quentin Sallembien, Weiwei Fang, Stéphane Grass, Jérôme Lacour, Laurent Bouteiller, Matthieu Raynal
     Chem. Sci. 2025, 16, 14584-14594

The induction and transmission of chirality across multiple length scales is fundamental to many (bio)chemical processes. For the majority of macromolecular and supramolecular structures adopting a helical configuration, this is harnessed by means of a monomer embedding a stereogenic element, also called a “sergeant” because of its ability to transfer its chirality preference to achiral monomers. Herein, we devise a triarylamine trisamide (TATA) monomer embedding a (thio)urea unit able to interact with a chiral phosphate anion through hydrogen bonding. Thanks to the orthogonal nature of the amide and (thio)urea functions, the anion specifically binds to the (thio)urea unit, thus yielding a supramolecular monomer acting as a “sergeant” i.e. allowing efficient chirality induction in amide-bonded TATA helical copolymers composed of various types of achiral TATA monomers. Unlike covalent “sergeants”, chirality can be induced in situ by binding of the chiral anion to pre-formed coassemblies. In addition, the catalytic performance of TATA coassemblies embedding intrinsically achiral phosphine-functionalized TATA monomers has been evaluated: higher enantioselectivities are reached with the supramolecular versus covalent “sergeant”. Our work may facilitate the design and development of supramolecular “sergeants” as a modular approach to induce chirality in supramolecular helical copolymers and catalysts.

DOI : 10.1039/D5SC02159F