Supramolecular copolymerization through self-correction of non-polymerizable transient intermediates

Kinetic control over structures and functions of complex assembly systems has aroused widespread interest. Understanding the complex pathway and transient intermediates is helpful to decipher how multiple components evolve into complex assemblies. However, for supramolecular polymerizations, thorough and quantitative kinetic analysis is often overlooked. Challenges remain in collecting the information of structure and content of transient intermediates in situ with high temporal and spatial resolution. Here, the unsolved evolution mechanism of a classical self-sorting supramolecular copolymerization system was addressed by employing multidimensional NMR techniques coupled with a microfluidic technique. Unexpected complex pathways were revealed and quantitatively analyzed. A counterintuitive pathway involving polymerization through the 'error-correction' of non-polymerizable transient intermediates was identified. Moreover, a 'non-classical' step-growth polymerization process controlled by the self-sorting mechanism was unraveled based on the kinetic study. Realizing the existence of transient intermediates during self-sorting can encourage the exploitation of this strategy to construct kinetic steady state assembly systems. Moreover, the strategy of coupling a microfluidic technique with various characterization techniques can provide a kinetic analysis toolkit for versatile assembly systems. The combined approach of coupling thermodynamic and kinetic analyses is indispensable for understanding the assembly mechanisms, the rules of emergence, and the engineering of complex assembly systems.

Automated summary

Kinetic control over structures and functions of complex assembly systems has sparked widespread interest. In this study, the evolution mechanism of a classical self-sorting supramolecular copolymerization system was investigated using multidimensional NMR techniques and a microfluidic technique. Unexpected complex pathways and a counterintuitive polymerization process were revealed and quantitatively analyzed. Understanding the existence of transient intermediates during self-sorting can inspire the development of kinetic steady state assembly systems. The combination of a microfluidic technique and various characterization techniques provides a kinetic analysis toolkit for versatile assembly systems. The thermodynamic and kinetic analyses are essential for understanding the assembly mechanisms and engineering complex assembly systems.