Merging Supramolecular and Covalent Helical Polymers: Four Helices Within a Single Scaffold

Abstract

Supramolecular and covalent polymers share multiple structural effects such as chiral amplification, helical inversion, sergeants and soldiers, or majority rules, among others. These features are related to the axial helical structure found in both types of materials, which are responsible for their properties. Herein a novel material combining information and characteristics from both fields of helical polymers, supramolecular (oligo( p -phenyleneethynylene) (OPE)) and covalent (poly(acetylene) (PA)), is presented. To achieve this goal, the poly(acetylene) must adopt a dihedral angle between conjugated double bonds (ω1) higher than 165°. In such cases, the tilting degree (Θ) between the OPE units used as pendant groups is close to 11°, like that observed in supramolecular helical arrays of these molecules. Polymerization of oligo[( p -phenyleneethynylene) n ]phenylacetylene monomers ( n = 1, 2) bearing L -decyl alaninate as the pendant group yielded the desired scaffolds. These polymers adopt a stretched and almost planar polyene helix, where the OPE units are arranged describing a helical structure. As a result, a novel multihelix material was prepared, the ECD spectra of which are dominated by the OPE axial array.

Unexpected chirality transition and inversion mediated by dissolution–aggregation and the odd–even effect

“…To distinguish the origin of bisignate CD signals in these two negative states, we further performed ltration experiments. 32 As shown in Fig. S12b, † the CD signal and UV-vis absorption of PAzo-L-3 in DCE solution before and aer ltration were basically unchanged.…”

“…Although the transition between the secondary chirality and tertiary chirality in polymers plays an important role in nature, the interactive connection of the above two different hierarchical chiralities has been rarely studied. The control of chirality inversion in polymer systems mainly focuses on the regulation of the helical conformation of the main-chain conjugated polymers in a dissolved state [29][30][31][32][33] or supramolecular chirality of polymer assemblies in an aggregated state. 34,35 Malashkevich et al reported that macromolecular-to-supramolecular helicity inversion existed in cartilage oligomeric matrix proteins.…”

Diastereomeric multi‐chiral pendant groups: Their key role in stimuli‐responsive polymeric responses

“… 19 , 20 , 21 To be functional, these helical polymers must adopt macromolecular helical structures with screw sense excess. This can be achieved using supramolecular interactions with different external stimuli, 22 , 23 by controlling the conformational composition of the pendant groups 24 , 25 , 26 , 27 or by means of different chiral communication mechanism like Sergeants and Soldiers Effect, 28 , 29 , 30 , 31 Majority Rules, 32 , 33 Chiral Coalition, 34 Chiral Harvesting, 35 , 36 , 37 or Chiral Teleinduction 38 among others.…”

Chiroptical and colorimetric switches based on helical polymer-metal nanocomposites preparedviaredox metal translocation of helical polymer metal complexes

“…To overcome this obstacle, it is necessary to explore other helical macromolecules to decorate MNPs. In this sense, stimuli-responsive synthetic helical polymers 12–48 are excellent candidates to prepare helical polymer-MNP nanocomposites where the two chiralities of the helix can be explored in different fields. From the literature, it is known that the main limitation of the use of dynamic helical polymers as coating agents to prepare helical polymer-MNP nanocomposites is the functional group used to link the macromolecule to the metal nanoparticle.…”