Supramolecularly Catalyzed Polymerization: From Consecutive Dimerization to Polymerization

Discovery of non-classical complex models between a cationic water-soluble pillar[6]arene and naphthalenesulfonate derivatives and their self-assembling behaviors

Molecular recognition based on cationic water-soluble pillar[n]arenes shows considerable advantages in their application in biological and environmental systems, such as excellent anion-binding ability and antimicrobial properties. Unique complex models are discovered in this work where a cationic water-soluble pillar[6]arene binds with disodium 1,5-naphthalenedisulfonate and disodium 2,6-naphthalenedisulfonate at the ratio of 1 : 2, which is proven by results from nuclear magnetic resonance spectroscopy, isothermal titration calorimetry, fluorescence spectroscopy experiments and transmission electron microscopy.

Host-Guest Chemistry in Supramolecular Theranostics

Macrocyclic hosts, such as cyclodextrins, calixarenes, cucurbiturils, and pillararenes, exhibit unparalleled advantages in disease diagnosis and therapy over the past years by fully taking advantage of their host-guest molecular recognitions. The dynamic nature of the non-covalent interactions and selective host-guest complexation endow the resultant nanomaterials with intriguing properties, holding promising potentials in theranostic fields. Interestingly, the differences in microenvironment between the abnormal and normal cells/tissues can be employed as the stimuli to modulate the host-guest interactions, realizing the purpose of precise diagnosis and specific delivery of drugs to lesion sites. In this review, we summarize the progress of supramolecular theranostics on the basis of host-guest chemistry benefiting from their fantastic topological structures and outstanding supramolecular chemistry. These state-of-the-art examples provide new methodologies to overcome the obstacles faced by the traditional theranostic systems, promoting their clinical translations.

Humidity- and Temperature-Tunable Multicolor Luminescence of Cucurbit[8]uril-Based Supramolecular Assembly

Fabrication of tunable luminescent materials by a single luminophore is a challenge owning to the limit of emissive properties of monofluorophores. Herein, a type of temperature and humidity dual-responsive luminescent material based on host-guest supramolecular self-assembly was developed. Included into the cavity of cucurbit[8]uril (CB[8]) to form a 1:2 host-guest binding motif, the highly blue-emissive thiazolothiazole methyl-viologen (TMV) molecules were promoted to stack closely with a sharp luminescence decrease at 460 nm and rise of the dimer emission at 535 nm, especially at high concentrations in aqueous solution, which was demonstrated by fluorescence spectra, UV-vis absorbance spectra, NMR, and ITC data. Accordingly, when printed on paper, the 1/2 CB[8]/TMV complex presented a reversibly humidity-dependent emissive behavior with luminescent color changing from greenish-yellow in wet to blue upon evaporation. Besides, the  sensitivity of the host-guest interaction endowed the CB[8]/TMV complexes with temperature-tunable emission which showed a considerably enhanced blue luminescence at higher temperature. Subsequently, a ratiometric temperature-responsive emitter which luminesced reversibly from pink to white and then to blue light at temperature ranging from 0 to 70 °C was fabricated by mixing the CB[8]/TMV complex with thermal-sensitized emitting GSH-Au nanoclusters. These fine-tuning abilities make the CB[8]/TMV supramolecular complex applicable in visual luminescent devices such as anti-counterfeiting labels and fluorescent thermometers.

Hierarchically Compartmentalized Supramolecular Gels through Multilevel Self-Sorting

Hierarchical compartmentalization through the bottom-up approach is ubiquitous in living cells but remains a formidable task in synthetic systems. Here we report on hierarchically compartmentalized supramolecular gels that are spontaneously formed by multilevel self-sorting. Two types of molecular gelators are formed in situ from nonassembling building blocks and self-assemble into distinct gel fibers through a kinetic self-sorting process; interestingly, these distinct fibers further self-sort into separated microdomains, leading to microscale compartmentalized gel networks. Such spontaneously multilevel self-sorting systems provide a "bottom-up" approach toward hierarchically structured functional materials and may play a role in intracellular organization.

Forming a water-soluble supramolecular polymer and an AIEE hydrogel: two novel approaches for highly sensitive detection and efficient adsorption of aldehydes

Two novel approaches for highly sensitive detection and efficient adsorption of aldehydes by forming a water-soluble supramolecular polymer and an AIEE hydrogel.

A cucurbituril/polysaccharide/carbazole ternary supramolecular assembly for targeted cell imaging

A ternary supramolecular assembly with near-infrared lysosome imaging and targeted photodynamic therapy properties was successfully orthogonally constructed in a two-step assembly manner.

Photoreaction-driven two-dimensional periodic polyrotaxane-type supramolecular nanoarchitecture

A stable 2D supramolecular assembly was constructed with photoreaction-driven transformation from polypseudorotaxane to polyrotaxane, which could capture C₆₀ in water and present excellent DNA cleavage ability and photodynamic therapy effect.

Cucurbit[7]uril promoted Fenton oxidation by modulating the redox property of catalysts

The redox property of a ferrocene derivative is modulated by cucurbit[7]uril, thus accelerating the catalytic oxidation of dye chromophores.

Red-light-responsive molecular encapsulation in water: an ideal combination of photochemistry and host–guest interaction

Red-light-responsive CB[8]-mediated host–guest system featured with high photoisomerization ratio was fabricated which could be used as molecular container with red-light-activated release ability.

Reversible hydrogel dynamics by physical–chemical crosslink photoswitching using a supramolecular macrocycle template

Host–guest supramolecular hydrogels are prepared from light-responsive guests within a CB[8] cavitand, and the complex catalyzes reversible guest photodimerization.

Cucurbit[8]uril-Based Polymers and Polymer Materials

Cucurbit[8]uril (CB[8]) is unique and notable in the cucurbit[n]uril family, since it has a relatively large cavity and thus is able to simultaneously accommodate two guest molecules. Typically, an electron-deficient first guest and an electron-rich second guest can be bound by CB[8] to form a stable 1:1:1 heteroternary supramolecular complex. Additionally, two homo guests can also be strongly dimerized inside the cavity of CB[8] to form a 2:1 homoternary supramolecular complex. During the past decade, by combining polymer science and CB[8] host-guest chemistry, a variety of systems have been established to construct supramolecular polymers with polymer chains typically at the nanoscale/sub-microscale, and CB[8]-based micro/nanostructured polymer materials in the form of polymer networks and hydrogels, microcapsules, micelles, vesicles, and colloidal particles, normally in solution and occasionally on surfaces. This Review summarizes the noncovalent interactions and strategies used for the preparation of CB[8]-based polymers and polymer materials with a focus on the representative and latest developments, followed by a brief discussion of their characterization, properties, and applications.

Photocontrolled reversible conversion of a lamellar supramolecular assembly based on cucurbiturils and a naphthalenediimide derivative

Lamellar and helical supramolecular assemblies were constructed using cucurbiturils and a naphthalenediimide derivative. The formation of the lamellar assembly could be reversibly photocontrolled.