Dynamic Covalent Hydrazone Supramolecular Polymers toward Multiresponsive Self-Assembled Nanowire System

Stimuli-responsive
polymeric systems are of considerable interest
due to their potential applications in environment-adaptive technologies
such as smart surfaces. Traditionally, such systems can be constructed
either by dynamic noncovalent (supramolecular) or dynamic covalent
chemistry, but the use of both chemistries in one system may offer
unique opportunities for structural diversity and various controllability.
Herein, we report that hydrazone–pyridinum conjugates, which
can be dynamically exchanged by transimination, assemble to form one-dimensional
nanowires due to direct intermolecular interactions (without metal-ion coordination). The self-assembly process can
be controlled not only by dynamic covalent chemistry but also by pH
adjustment. The hydrazone–pyridinum conjugates are transformed
to merocyanine-type dyes of distinctive negative solvatochromism via
deprotonation, which also affects their self-assembly. Such a dual
control of the dynamic molecular assembly will provide unique way
to develop diverse smart nanomaterials with multistimuli-responsiveness.