The formation of helical structures through the supramolecular polymerization of a variety of self‐assembling units is reviewed. These scaffolds are usually obtained by efficient transfer or amplification of chirality phenomena, in which the starting self‐assembling molecules possess different elements of asymmetry, such as point or axial chirality. Relevant examples of helical supramolecular structures investigated under thermodynamic control are reviewed, and the helical outcome of remarkable examples of chiral entities obtained through kinetic control are also highlighted. Finally, selected examples of flexible macroscopic chirality and catalysis are described to illustrate the applicability of helical aggregates.

Herein, the synthesis and self-assembling features of N-heterotriangulenes 1-3 decorated in their periphery with 3,4,5-trialkoxy-N-(alkoxy)benzamide moieties that enable kinetic control of the supramolecular polymerization process are described. The selection of an appropriate solvent results in a tunable energy landscape in which the relative energy of the different monomeric or aggregated species can be regulated. Thus, in a methylcyclohexane/toluene (MCH/Tol) mixture, intramolecular hydrogen-bonding interactions in the peripheral side units favor the formation of metastable inactivated monomers that evolve with time at precise conditions of concentration and temperature. A pathway complexity in the supramolecular polymerization of 1-3 cannot be determined in MCH/Tol mixtures but, importantly, this situation changes by using CCl . In this solvent, the off-pathway product is a face-to-face H-type aggregate and the on-pathway product is the slipped face-to-face J-type aggregate. The autocatalytic transformation of the metastable monomeric units, as well as the two competing off- and on-pathway aggregates allow the realization of seeded and living supramolecular polymerizations. Interestingly, the presence of chiral, branched side chains in chiral (S)-2 noticeably retards the kinetics of the investigated transformations. This work brings to light the relevance of controlling the pathway complexity in self-assembling units and opens new avenues for the investigation of complex and functional supramolecular structures.

The helical stereomutation in the kinetically controlled coassembly of the reported carbonyl-bridged triarylamines (CBTs) is described. The copolymerization of chiral CBTs (S)-1 or (R)-1 with achiral 2 in sergeants-and-soldiers (SaS) experiments results in at unable helicity conditioned by the percentage of the chiral sergeant and by the cooling rate. The dissimilar inherent chirality of the extended monomeric (M) and intramolecularly H-bonded metastable (M*) species, as well as the different stability of the kinetic trap of the chiral CBTs (S)-1/(R)-1 and the achiral CBT 2,c ondition the chirality transfer and afford J-aggregates of inverse handedness.

The chiroptical features of supramolecular polymers formed from N-heterotriangulenes 1-3 have been investigated by circular dichroism (ECD) and vibrational circular dichroism (VCD) techniques. In solution, the CD spectra demonstrate that the helicity of the aggregates depends on only the stereogenic centres located at the peripheral chains. In the gel state, the chiroptical features are conditioned by the point chirality of the stereogenic centres and by the achiral solvent utilised. Sonication of the gels formed in CCl reveals both kinetic and thermodynamic phases. These findings reveal the presence of pathway complexity in the gel state triggered by sonication. The described solvent-induced helical stereomutation demonstrates that the gel state can be utilised as an outstanding benchmark for investigating uncommon chiroptical effects and to explore the rules of chirality transmission.

Hierarchical organization of self-assembled structures into superstructures is omnipresent in Nature but has been rarely achieved in synthetic molecular assembly due to the absence of clear structural rules.W eh erein report on the selfassembly of scissor-shaped azobenzene dyads which form discrete nanotoroids that further organizei nto 2D porous networks.T he steric demand of the peripheral aliphatic units diminishes the trend of the azobenzene dyad to constitute stackable nanotoroids in solution, thus affording isolated (unstackable) nanotoroids upon cooling. Upon drying, these nanotoroids organizea tg raphite surface to form well-defined 2D porous networks.The photoirradiation with UV and visible light enabled reversible dissociation and reconstruction of nanotoroids through the efficient trans$cis isomerization of azobenzene moieties in solution.