Themed collection Host-Guest Chemistry

Host–guest supramolecular ensembles constructed by various electroactive oligopyrrolic molecular containers capable of spherical guest (e.g., Buckminster fullerenes) complexation are described in this Feature Article.

Supramolecular host–guest chemistry of calixarenes has been well explored based on spectroscopy, though their architectures can only be revealed through microscopy. Therefore, this article brings out microscopy features into light in a comparative manner.

In this review, we summarize the advance of stimuli-responsive pillararene modified nanosystems for controlled release of drugs from the perspectives of decomposition release and gated release, and describe in detail the controlled release of recently developed photo-, pH-, thermal-, chemical- and multi-responsive nanosystems.

The molecular tweezer CLR01 binds to the choline head group of phospholipids inside lipid rafts, raises local surface tension and thus disrupts viral membranes.

Helical building blocks can self-assemble into supramolecular helices via head-to-tail intermolecular interactions, wherein good propagation of helicity operates, exhibiting favourable homochiral elongation and functional helical channel structures.

The diversity of aromatic building blocks, bridging groups, and their connection patterns determines the richness of macrocyclic host molecules (MHMs). The MHMs with new aromatic building blocks reported in the last ten years were summarized and discussed.

We summarize recent progress in the enhanced delivery of biomacromolecular therapeutics for disease treatment using metal–organic frameworks (MOFs) as host materials.

This feature article reviews the structural design, synthetic methods, and multi-field applications of covalently bridged pillararene-based oligomers (CBPOs).

A novel supramolecular assembly built from Keggin-type polyoxometalates and [18]crown-6 ether building blocks was first applied as sulfur host in lithium–sulfur batteries to resolve remaining critical challenge of polysulfide shuttle effect.

An economic and energy-efficient adsorptive molecular sieving approach is demonstrated for the separation of the cis-DCE isomer with a purity of ∼96% using trianglimine macrocycles.

Unexpected strongly luminescent complexes were constructed via the weakly luminescent [1]rotaxane coordinating with Zn²⁺ specifically due to the coordination-induced emission effect.

A calix[6]arene with three preorganised halogen bond donating groups gives >100-fold selectivity for Cl⁻ uniport over HCl symport, in contrast to analogous compounds with strong hydrogen bond donating groups.

Nanoscopic lateral confinement created on a graphite surface enabled the study of embryonic stages of molecular self-assembly on solid surfaces using scanning tunneling microscopy performed at the solution/solid interface.

The most efficient anion transporters are those that agree with Lipinski's rule-of-lipophilicity, exhibiting a partition coefficient (clog P_o/w) close to 5.

A bimane ditriazole–copper(II) complex serves as an ultrasensitive water sensor. Key features of the system also include rapid response times and good selectivity for water compared to other protic solvents.

An easy to operate and energy-saving adsorptive separation method using nonporous adaptive crystals of rim-differentiated pillar[5]arene (RDP[5]) was developed. The adaptive RDP[5] crystals separate dichloromethane from a halomethane mixture with 99.1% purity.

A large-sized carbazole macrocycle shows size-dependent recognition towards large-volume tetrapropylammonium salts.

The precise synthesis of novel rotaxane-branched radical dendrimers with up to 24 TEMPO radicals as termini was achieved.

Helical folding of a carbazole–pyridine oligomer generates a tweezer-type binding cavity which allows for the intercalation of a naphthalenediimide guest.

A triple-stranded metallo-supramolecular helicate based on 2,7-disubstituted triptycene was easily constructed, and shows efficient encapsulation of quaternary ammonium guests.

Metallogelators/metallogels derived from a series of NSAID-based Zn(II) coordination complexes have been developed as plausible multi-drug self-delivery systems.

A combination of isothermal titration calorimetry experiments and molecular dynamics simulations reveal how the NrtA protein recognizes nitrate versus nitrite in water.

A hydrogel scaffold with a non-fouling but specific cancer cell-adhesive surface fabricated via host–guest interactions captures cancer cells and promotes growth and release of multicellular spheroids.

A hybrid nanoplatform was fabricated using a tower[6]arene sodium salt as a stabiliser on the surface of silver nanoparticles, showing good performance in catalysis and detection.

Linear polymers containing pillar[5]arenes as the pendant groups were designed and synthesized via a ring-opening metathesis polymerization. Such polymers could exhibit tunable fluorescence properties based on the host–guest interactions.

A pseudo-slide-ring network is introduced to enhance the hydrogel's mechanical performance, providing anti-freezing property and ionic conductivity.

Artificial molecular muscles are of interest in the nanosciences but their theoretical treatment is demanding. We present a standardized protocol on how to obtain reliable structures and free energies applying GFN quantum chemistry methods.

Hydrogen peroxide–PVP used in tooth whitening involves a chain of hydrogen bonded H₂O₂ molecules that can be selectively substituted by water molecules.

A water-soluble tetralactam macrocycle is synthesized and characterized. This macrocycle is able to strongly bind riboflavin (K_a >10⁷ M⁻¹) in water and provides strong photoprotection of riboflavin upon UV irradiation.

This work presents the facile synthesis of monodisperse hierarchical nanoflowers by aqueous polymerization-induced self-assembly (PISA), modulated by host–guest interaction.

A high-affinity supramolecular dye-capture system with “turn on” visible fluorescence is used to create a new assay for phospholipase-mediated liposome leakage.

This work reports the synthesis of four photoresponsive macrocycles and their selective binding and release of SO₄²⁻via light irradiation.

Two imine-based calix[4]arene assemblies were selectively formed by changing the conformation of the precursor by Na⁺ binding; the flattened and spread cone conformations gave a macrocyclic trimer and a capsular-shaped dimeric cage, respectively.

A novel approach to efficient and selective synthesis of [4]rotaxane with two stations was proposed to demonstrate the superiority of H-bonded azo-macrocycles in forging higher order rotaxanes.

Pillar[5]arene–acid-based supramolecular adhesives with tough adhesion performances on different substrates were obtained.

A pillar[5]arene functionalized with multiple binding sites can detect 1,8-diaminooctane, 1,10-diaminodecane, and 1,12-diaminododecane selectively and sensitively by using the AIE mechanism and the induced-fit mechanism.

Chemometrics-coupled chiral recognition was conducted with boronate ensembles containing D–π–A cyanostilbenes to determine and predict enantiomer excess for guest amines.

Dendronized polydiacetylenes showing thermoresponsiveness were fabricated via photopolymerization of assembled ribbons from amphiphilic dendronized diacetylene in aqueous solutions, which simultaneously showed thermally switchable chiralities.

A supramolecular dual protein sensing approach embedded with protein–ligand binding features and enzyme-cleavable moiety activating multichannel fluorescence signals via three different mechanisms.

We studied the influence of calixarene structure on transport efficiency of peptides, and provide meaningful information for transport systems.

Intercomponent interactions in polyrotaxane glass influenced the mobility of the threading polymer confined in the glassy host framework, resulting in markedly different mechanical properties.

Self-sorting regimes are controlled by adjusting steric interactions in self-assembled coordination cages and equilibration followed by HPLC. Statistical or biased distributions can be obtained, including isolation of a single heteroleptic species.

Macrocyclic iodine(I) complexes with 5–10 Å cavity act as host molecules and encapsulate hexafluorophosphate anions in the gas phase confirmed by ion-mobility spectrometry and DFT calculations.

Polypseudorotaxanes constructed from pillar[5]arene rings and polyamide chains were successfully synthesized by interfacial polymerization of polyamide in the presence of pillar[5]arene.

Host–guest interactions between rationally designed fluorescent probes enable the visualization of lipophagy in live cells.

Neutral tetradentate halogen bonding macrocycles bind a range of halide and dicarboxylate anion species in up to 40% water by volume containing aqueous-organic solvent media

A [2.2]paracyclophane-bridged bimetallic alkynylplatinum(II) terpyridyl complex displays severe emission quenching due to the presence of intramolecular π–π interactions.

Herein, we describe self-sorting supramolecular polymerization that uses chiral calix[5]arene hosts and a dumbbell-shaped fullerene guest.

Six-residue aromatic oligoamide macrocycles bind bipyridinium guest G to form stable, compact pseudo[3]rotaxanes with strong positive cooperativity.

We report a chemiluminescent probe that permits the paired detection of tyrosinase (Tyr) and biological thiols. The Tyr-formed benzoquinone intermediate reacts with GSH and produces an enhanced chemiluminescence response.

A dynamically reversible two-dimensional (2D) protein assembly system was designed based on host–guest interactions.

A layered network supramolecular assembly is constructed by a tri-β-cyclodextrin-armed host and di-azobenzene-decorated polyoxometalate guest for degradation of selective dyes and partner-joined acceleration in water and dichloromethane in air.

A porous water-soluble supramolecular organic framework efficiently exhibiting phosphorescence was developed both in an aqueous phase and in film state at room-temperature.

Structurally defined Pd₄L₈ and Pd₆L₁₂ coordination cages are obtained from low-symmetry dipyridyl ligands.

Supramolecular polymer micelles are formed by host–guest interaction of cyclodextrin- and adamantane-terminated polypeptides and polycaprolactones. Enzyme degradation of the micelles leads to a controlled release of payload.

A new supramolecular system was constructed based on water-mediated hydrogen bonding between a benzimidazole functionalized host, water and guest. Intriguingly, these hosts can recognize small hydrophilic guests in water through the synergistic action of water-mediated hydrogen bonding and hydrophobic effects.

A galactose-targeting supramolecular photosensitizer system DOX@GP5⊃NBSPD was constructed based on a host–guest inclusion complex, which could achieve the enhanced hypoxic-tumor therapeutic effectiveness by chemo-photodynamic combination.

Synergistic covalent-and-supramolecular polymers connected by [2]pseudorotaxane moieties are designed and synthesized, whose unique topological structures lead to materials with mechanically adaptive properties.

A new series of π-extended quinone derivatives containing a pyrrole bridge exhibited NH/OH-type tautomerization and anion binding along with deprotonation that induced near-infrared absorption and ion-pairing assemblies.

A conjugated polymer material integrated with pillararenes and codoped with heteroatoms was constructed for band-structure engineering and photocatalytic dye degradation.

pH-dependent liposomal assays are often used to determine anion selectivity in transmembrane anion transport experiments. In this communication, we discuss the validity and limitations of these assays, and provide guidelines for their use to avoid misleading results.