Dynamic supramolecular complexes constructed by orthogonal self-assembly.

CONSPECTUS: Supramolecular complexes, including various low-molecular-mass structures and large molecular aggregates that are assembled by reversible and highly directional noncovalent interactions, have attracted more and more attention due to their fascinating and unconventional chemical and physical properties that are different from those of traditional architectures encountered by covalently linked backbones. Supramolecular complexes are by nature dynamic architectures considering the reversibility of noncovalent interactions by which small molecular monomers can assemble into specific architectures that are able to be repeatably reorganized through the assembly/disassembly processes under certain environmental factors such as temperature, concentration, and solvent conditions. The construction of supramolecular complexes by orthogonal self-assembly with different types of highly specific, noninterfering interactions is currently attracting considerable interest since they not only can dynamically self-assemble, but also can be tuned by various external stimuli through addressing each type of noncovalent interaction separately. Therefore, these dynamic supramolecular complexes, especially with external responsiveness, represent the most outstanding candidates for the future development of functional and smart materials, and even mimic the assembling process of natural systems. In this Account, we will summarize the recent advances of dynamic supramolecular complexes constructed by orthogonal self-assembly in soluiton in two sections: (1) Construction strategies for supramolecular complexes based on orthogonal self-assembly, whose dynamic behaviors with external responsiveness were not experimentally investigated but potentially existed due to the intrinsic reversibility of noncovalent bonds; (2) dynamic behaviors of multiresponsive supramolecular complexes, which were experimentally reported to exhibit reversible multi-responsiveness to external stimuli. Dynamic nature is one of intrinsic properties of supramolecular complexes constructed by self-assembly. Therefore, in the first section, we will describe the dynamic self-assembly in the construction of supramolecular complexes, but will focus on their external responsive dynamic behaviors in the second section. In addition, considering that an increasing number of supramolecular complexes constructed by biological building blocks through bio-orthogonal assembly as mimics of biological systems have been reported in recent years, in the second section we will also present some typical examples on such special dynamic biological supramolecular complexes. The final part of this Account is devoted to foreseeing the rapid development of dynamic supramolecular complexes toward applications in functional and smart materials and fundamental questions facing dynamic supramolecular complexes in the future.