Pseudocryptand-Type [3]Pseudorotaxane and “Hook-Ring” Polypseudo[2]catenane Based on a Bis(m-phenylene)-32-crown-10 Derivative and Bisparaquat Derivatives

Macrocycle-Based Solid-State Supramolecular Polymers

Supramolecular polymers, generated by connecting monomers through noncovalent interactions, have received considerable attention over the past years, as they provide versatile platforms for developing diverse aesthetically pleasing polymeric structures with promising applications in a variety of fields, such as medicine, catalysis, and sensing. In the development of supramolecular polymers, macrocyclic hosts play a very important role. Benefiting from their abundant host-guest chemistry and self-assembly characteristics, macrocycles themselves or their host-guest complexes can self-assemble to form well-ordered supramolecular polymeric architectures including pseudopolyrotaxanes and polyrotaxanes. The integration of these topological structures into supramolecular polymeric materials also imbues them with some unforeseen functions. Current interest in macrocycle-based supramolecular polymers is mostly focused on the development of supramolecular soft materials in solution or gel-state, in which the dynamic nature of noncovalent interactions endows supramolecular polymers with a wealth of "smart" properties, such as multiresponsiveness and self-repair capabilities. While preparation of macrocycle-derived supramolecular polymers in the solid state is a relatively challenging but intriguing prospect, they are an important part of the field of supramolecular polymers. On one hand, the construction of macrocycle-based solid-state supramolecular polymers enables us to obtain new materials with novel properties and functions such as mechano-responsiveness. On the other hand, the molecular structures and arrangements in these materials are well-identified by X-ray crystallography techniques, offering a direct visual representation of the supramolecular polymerization process. The analysis of the role of noncovalent interactions in these architectures allows us to design more sophisticated and elegant supramolecular polymers in a highly rationalized and controllable manner. This Account serves to summarize the research progress on macrocycle-based solid-state supramolecular polymers (MSSPs), including the contributions toward this field made by our group. For constructing MSSPs, the key point is to control noncovalent interactions. Thus, in this Account, we primarily classify these MSSPs by different noncovalent interactions involved to connect the monomers, including metal-ligand interactions, host-guest interactions, π···π stacking, and halogen bonding. These noncovalent interactions are highly associated with the structures and functions of the resultant MSSPs. For instance, using metal-ligand interactions as driving forces, metal clusters can be introduced in MSSPs which afford systems with solid-state luminescence or proton conduction properties; supramolecular polymerization using macrocycle-based host-guest interactions can modulate the molecular arrangement of some specific molecules in the solid state, which further influences their solid-state properties; π···π stacking interactions and halogen bonding give chemists more choice to design MSSPs with various elements. The role of macrocyclic hosts in MSSPs is also revealed in these descriptions. Finally, the remaining challenges are identified for further development of future prospects. We hope that this Account can inspire new discoveries in the realm of supramolecular functional systems and offer new opportunities for the construction of supramolecular architectures and solid-state materials.

Multistimuli-Responsive and Photocontrolled Supramolecular Luminescent Gels Constructed by Anthracene-Bridged Bis(dibenzo-24-crown-8) with Secondary Ammonium Salt Polymer

A novel multistimuli-responsive and photcontrolled supramolecular luminescent gel is fabricated from anthracene-bridged bis(dibenzo-24-crown-8) (1) and secondary ammonium salt-functionalized graft polymer (3). X-ray crystallographic analysis reveals that the dibenzo-24-crown-8 (DB24C8) ring is located at the opposite site of 1, which will greatly hinder the mutual intermolecular π-π stacking between anthracene groups. By taking advantage of the controllable binding of 1 with 3, the unique gel-sol transition could occur under different temperatures, pH, and competitive guest bindings. Benefiting from the photo-oxygenation of anthracene, the luminescence behavior of the supramolecular gel could be switched off and on under UV light (365 nm) and heating treatment, which provides a new approach for constructing photocontrolled supramolecular luminescent gel.

Cu(ii) templated formation of [n]pseudorotaxanes (n = 2, 3, 4) using a tris-amino ether macrocyclic wheel and multidentate axles

The systematic development of mono-, bi- and tri-nuclear [n]pseudorotaxanes (n = 2, 3, 4) via Cu(ii) templation and π–π stacking interactions.

A [2]pseudorotaxane based on a pillar[6]arene and its application in the construction of a metallosupramolecular polymer

A novel metallosupramolecular polypseudorotaxane was constructed by pillar[6]arene-based host–guest recognition and metal coordination.

A three-armed cryptand with triazine and pyridine units: synthesis, structure and complexation with polycyclic aromatic compounds

The aromatic nucleophilic substitution reaction based synthesis of a three-armed cryptand displaying 2,4,6-triphenyl-1,3,5-triazine units as caps and pyridine rings in the bridges, along with NMR, MS and molecular modelling-based structural analysis of this compound are reported. Appropriate NMR and molecular modelling investigations proved the formation of 1:1 host–guest assemblies between the investigated cryptand and some polynuclear aromatic hydrocarbons or their derivatives.

Supramolecular control over pillararene-based LCST phase behaviour

Based on the supramolecular interactions between pillar[5]arenes and ionic liquids, supramolecular control was successfully introduced into thermo-responsive systems to adjust LCST phase behaviour in water.

Taco complex-templated highly regio- and stereo-selective photodimerization of a coumarin-containing crown ether

We design a coumarin-containing bis(m-phenylene)-32-crown-10 derivative which efficiently controls the regio- and stereo-selectivity of the photodimerization of its two terminal coumarin groups templated by taco-type host–guest complex formation to selectively produce the syn-head-to-tail cryptand isomer in quantitative yield.

A multiple-responsive water-soluble [3]pseudorotaxane constructed by pillar[5]arene-based molecular recognition and disulfide bond connection

A multiple-responsive water-soluble [3]pseudorotaxane was constructed by water-soluble pillar[5]arene-based molecular recognition and disulfide bond connection.

PO functional group-containing cryptands: from supramolecular complexes to poly[2]pseudorotaxanes

Host–guest systems based on PO functional group-containing cryptands and the corresponding supramolecular poly[2]pseudorotaxanes with different shapes were constructed successfully.

Three protocols for the formation of a [3]pseudorotaxane via orthogonal cryptand-based host-guest recognition and coordination-driven self-assembly

A novel bis(m-phenylene)-32-crown-10-based cryptand 1 with a pyridine nitrogen atom outside on the third arm was designed and synthesized. Subsequently, host-guest complexation between cryptand 1 and a selection of bipyridinium guests has been studied. More interestingly, the [3]pseudorotaxane 2 is a superset of 5(2) was obtained in three methods by utilizing the noninterfering orthogonal nature of coordination-driven self-assembly and host-guest interactions.

Stimuli-responsive supramolecular polymeric materials

Supramolecular materials, dynamic materials by nature, are defined as materials whose components are bridged via reversible connections and undergo spontaneous and continuous assembly/disassembly processes under specific conditions. On account of the dynamic and reversible nature of noncovalent interactions, supramolecular polymers have the ability to adapt to their environment and possess a wide range of intriguing properties, such as degradability, shape-memory, and self-healing, making them unique candidates for supramolecular materials. In this critical review, we address recent developments in supramolecular polymeric materials, which can respond to appropriate external stimuli at the fundamental level due to the existence of noncovalent interactions of the building blocks.