Transient dormant monomer states for supramolecular polymers with low dispersity

Krishnendu Jalani,Anjali Devi Das,Subi J George,Ranjan Sasmal,Sarit S Agasti

doi:10.1038/s41467-020-17799-w

Krishnendu Jalani, Anjali Devi Das + Show 3 more

Open Access

https://doi.org/10.1038/s41467-020-17799-w

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Abstract

Temporally controlled cooperative and living supramolecular polymerization by the buffered release of monomers has been recently introduced as an important concept towards obtaining monodisperse and multicomponent self-assembled materials. In synthetic, dynamic supramolecular polymers, this requires efficient design strategies for the dormant, inactive states of the monomers to kinetically retard the otherwise spontaneous nucleation process. However, a generalized design principle for the dormant monomer states to expand the scope of precision supramolecular polymers has not been established yet, due to the enormous differences in the mechanism, energetic parameters of self-assembly and monomer exchange dynamics of the diverse class of supramolecular polymers. Here we report the concept of transient dormant states of monomers generated by redox reactions as a predictive general design to achieve monodisperse supramolecular polymers of electronically active, chromophoric or donor-acceptor, monomers. The concept has been demonstrated with charge-transfer supramolecular polymers with an alternating donor-acceptor sequence.

Highlights

Controlled cooperative and living supramolecular polymerization by the buffered release of monomers has been recently introduced as an important concept towards obtaining monodisperse and multicomponent self-assembled materials
Reported metastable or intramolecular H-bonded dormant state designs for the living supramolecular polymerization cannot be extended for CT based systems, as they lack in hydrogen bonds and are highly dynamic to be trapped in high-energy metastable dormant states[16,17]
The reduced, unfolded polymerization of an amphiphilic charge-transfer monomer (PNF)-NDI− state exist in a self-assembled state due to the interactions between NDI radical anions and can be considered as a transient assembly which would oxidize back to the folded monomers in a temporal manner

Summary

Introduction

Controlled cooperative and living supramolecular polymerization by the buffered release of monomers has been recently introduced as an important concept towards obtaining monodisperse and multicomponent self-assembled materials. A similar strategy has been recently extended to many π-conjugated monomers, where seeded and cooperative growth were exploited for obtaining assemblies with precise degree of polymerization[20,21,22,23,24,25,26,27,28] In another independent and pioneering strategy, Aida and coworkers have reported a chain-growth supramolecular polymerization for monodisperse structures, by the design of conformationally dormant bowlshaped monomers with pre-organized intramolecular hydrogen bonding and corresponding N-methylated derivatives as initiator molecule with facially unsymmetric hydrogen bonding features[29]. Our group has recently introduced a bio-inspired, fuel-driven cooperative and living supramolecular polymerization approach by the design of stable dormant states, which can be grown under kinetic control by the binding of small molecules like ATP or a chemical reaction[30,31] These dormant states for the monomers remain in their inactive form unless triggered by a fuel and the rate of fuel generation or its binding action determines the kinetics of growth. The dispersity and molecular weight of these supramolecular polymers are highly dependent on its growth kinetics, which can be modulated by controlling the stability of dormant states and oxidation rates by varying concentration of reducing agent

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