Adaptive Covalent Networks Enabled by Dual Reactivity: The Evolution of Reversible Covalent Bonds, Their Molecular Assemblies, and Guest Recognition

Adaptive
chemistry allows transformation and selection within molecular
networks, and adaptive systems composed of different types of dynamic
covalent reactions (DCRs) are challenging. Herein, we demonstrate
dual reactivity-based covalent networks encompassing the regulation
of and switching between C–N- and C–S-based reversible
covalent assemblies. The creation and exchange of C–N- or C–S-derived
assemblies exhibiting diverse architectures, including linear structures,
macrocycles, and cages, were achieved. The shift of reactivity then
permitted the interconversion between C–N- and C–S-containing
assemblies. Moreover, the adaption of intramolecular and intermolecular
scaffolds was feasible via linker design. The latent hemiaminal chirality
center offered a pathway for the induction of chirality within assemblies.
Finally, switchable structural change and controlled extraction of
ions were realized with Hg2+ as a guest for macrocycles.
The remarkable complexity of networks described herein could open
the door for the utility in sophisticated functional systems.