Themed collection Host–guest chemistry

Endogenous protein labeling is one of the most invaluable methods for studying the bona fide functions of proteins in live cells.

We discuss the properties and potential future applications in catalysis, sensing and materials of ligands based on mechanically interlocked molecules.

Recent research progress in sensing based on induced supramolecular aggregation or disaggregation.

The failure of the Job plot, best-practice in uncertainty estimation in host–guest binding studies and an open access webportal for data analysis are reviewed in this Feature Article.

Calixarene based various 3D surface materials with unique signal amplification in molecular recognition are presented, including quantum dots (QDs), metal nanoparticles (NPs), nanotubes, and mesoporous silica.

Multicavity macrocyclic hosts are host molecules comprising more than one macrocyclic guest binding components connected through multipoint linkages.

Kinetic trapping via supramolecular approaches or physical processing pathways can be an efficient strategy for directing functional molecular self-assemblies.

Host–guest systems based on hyperbranched polymers together with their unique properties and various applications have been summarized.

In this feature article, we survey recent developments in host–guest chemistry studied in surface-adsorbed physisorbed supramolecular networks.

Molecular tweezers prevent tau deposition in mouse brains.

The assembly of proteins into various nano-objects with regular and periodic microstructures, i.e. protein arrays, is a fast-growing field in materials science.

This paper highlights the recent progress in the recognition and activation of molecules and anions by polyaza macrocyclic compounds.

This Feature Article reviews recent advances in the template-directed synthesis of porphyrin nanorings, including new templating methods, novel structures, and their applications in host–guest chemistry and artificial light-harvesting.

Post-translational methylation regulates the function of hundreds of proteins in profound ways, and is the target of many efforts to use host–guest chemistry to solve biochemical and biological problems.

This feature article covers the molecular recognition of pillar[5]arenes and neutral guests, and its application in making supramolecular structures, polymers and functional materials.

Recent progress in the construction of metal-coordination-assisted and covalently connected oligourea receptors and their anion coordination chemistry is presented.

Pillar[n]arenes (n = 5–15) are a novel class of macrocyclic molecules with hydroquinone as the repeating unit linked by methylene bridges at para-positions.

In this feature article, we covered recent progress in stimuli-induced polydiacetylenes for sensing temperature, chemical and biological targets.

Synthetic ZnDPA receptors are used for molecular imaging of disease and targeted therapeutics.

The development of solution-based anion receptor molecules which exploit halogen bonding interactions is an emerging area of research. This Feature Article reviews recent advances which have been made in this rapidly developing field, surveying the use of iodoperfluoroarene, haloimidazolium and halotriazole/triazolium halogen-bond-donor motifs in anion receptor design and describing the application of mechanically interlocked rotaxane and catenane frameworks as halogen bonding anion host systems.

This overview highlights how the high-energy ultraviolet or visible light required to drive photochemical reactions can be overcome by integrating the chromophores into supramolecular structures containing upconverting nanoparticles with trivalent lanthanide dopants (such as Tm³⁺ and Er³⁺).

We review the different approaches that have been used to form low molecular weight gels that respond to light.

Recent advances in emerging homogeneous supramolecular organic frameworks (SOFs) assembled through three-component host–guest chemistry in water are described.

In this feature article, we discuss recent developments in macroscopic contact angle switches formed by different macrocyclic hosts and highlight the properties of these new functional surfaces and their potential applications.

Carbohydrate biomarkers are particularly important targets for fluorescence imaging given their pivotal role in numerous important biological events. This review highlights the development of fluorescence imaging agents based on boronic acids.

Cyclic arrays of six zinc-porphyrin units are formed on which fullerene molecules are immobilized at the solid/liquid interface.

Glycosylated 4-amino-1,8-naphthalimide derivatives can be selectively hydrolysed in situ by glycosidase enzymes to release the naphthalimide as a fluorescent imaging agent.

We report the comprehensive structural and binding isotherm analyses of meso-3,5-dinitrophenyl-substituted calix[4]pyrroles with a variety of anions, displaying anion–π interactions.

Push–pull-functionalized ligands carrying molecular rotors assemble to [Pd₂L₄] coordination cages whose endohedral dynamics are controlled by the substitution pattern, solvent effects and guest encapsulation.

Cavity-containing macrocycles assemble, via side chain-dependent molecular packing, into various nanostructures able to bind cations in varying selectivities and capacities.

A box-like macrocycle was constructed efficiently (60% yield). Because the intramolecular rotations are restricted by water clusters around the ionic moieties, the box shows unique aggregation-induced emission enhancement property.

We present two approaches to low-molecular-weight supramolecular gels bearing hydrophobic cavities based on calixarene-containing building blocks.

Intramolecularly H-bonded urea moieties of aromatic oligoureas bind anions in modest affinities. Extending backbone length results in a cation-binding cavity, allowing the resultant oligomer to bind both anions and cations.

Indomethacin-guided cancer selective prodrug system activated by histone deacetylase and tumour-associated protease.

By state-of-the-art dispersion corrected density functional theory, the complexation properties of a recently synthesized halogen-bonded capsule with about 400 atoms are investigated and predictions for improved binding affinities are made.

A nanoporous membrane with tuneable permselectivity through non-covalent surface modification has been fabricated by deposition of a cucurbit[6]uril-based 2D polymer film onto a simple support membrane.

In this report, an orthogonal non-covalent interaction strategy based on specific recognition between sugar and protein, and host–guest interaction, was employed to construct artificial three dimensional (3D) protein assemblies in the laboratory.

We report the synthesis of a macrocyclic receptor that displays a selective fluorescent response to chloride in the solid state.

Supramolecular vesicles have been constructed based on the host–guest complexation, which show dual-responsiveness and cancer cells targetability.

The first solid state structure of a synthetic receptor-monosaccharide host–guest complex crystallized from water is reported.

A novel hybrid light-harvesting antenna with a srikaya-like structure of multi-graphene quantum dots (GQDs) as donors and one porphyrin unimolecular micelle as the acceptor was constructed through electrostatic self-assembly.

(±)-Tris-(4-methylthiazolyl)cyclotriguaiacylene forms chirally resolved clathrate complexes and self-assembles with Ag(I) to form a homochiral cubic coordination cage with spontaneous resolution.

Amenable to bendable: blocking the binding cleft enhances selectivity for flexible guests.

A Schiff base bearing coumarin is found to be an excellent indicator of trace amounts of moisture in organic solvents.

A fluorescent responsive BMP32C10-based cryptand host was successfully synthesized by introducing a 4-methylcoumarin group to the third arm of the cryptand.

Herein, we utilize a new, squaramide-based ligand, combined with a postsynthetic exchange (PSE) synthetic approach to prepare a series of Cu(II)–squaramide MOFs that are active catalysts for the Friedel–Crafts reaction.

The recognition of human growth hormone (hGH) by the synthetic host molecule cucurbit[7]uril (Q7) was predicted on the basis of its N-terminal phenylalanine. A resin presenting Q7 groups was prepared and shown to recognize hGH and insulin in the context of human serum.

A 3-dimensional networked molecular cage, NMC-1, has been synthesized that acts like a ‘molecular ship’ in a ‘breakable bottle’.

Pyrophosphate recognition using indicator displacement assays is compared to that of analogous receptors with covalently attached indicators.

Zn(II) and Cu(II) complexes are used in the recognition and sensing of adrafinil through an easy-to-detect fluorescence response.

This work reports a light-responsive reversible “one-to-two” morphological transition from vesicles to nanosheets and nanofibers in linear-hyperbranched supramolecular block copolymers.

This paper reports the binding properties of tetrameric pseudo-peptide receptors for protonated cytidines.

Two pseudopeptidic cages bind the EYE peptide motif of poly(EY) in buffered water, as shown by NMR and fluorescence spectroscopy. This supramolecular interaction protects the Tyr residues from the enzymatic phosphorylation by PTK.

Mono- and tetra-deprotonated 2-methylresorcinarene anions (1 and 2) as their trans-1,4-diammoniumcyclohexane (TDAC)²⁺ inclusion complexes are reported.

Bisphosphorylpillar[5]arene H2 binds strongly to alkyldiammonium ions and alkyl dihalides. The halogen bonds between H2 and alkyl dihalides lead to the rapid precipitation of the complex in water.

Unique LCST phase behaviour of imidazolium-based ionic liquids is reported, which can be controlled by concentration, the choice of cation, anion and solvent, and by supramolecular complex formation. MD simulations provide insight into the molecular basis of this LCST phenomenon.

A self-assembled and colorimetric sensor assay is utilized to monitor a model of a metabolic reaction where ATP is hydrolyzed to pyrophosphate and AMP.

Anion transporters were tested for antimicrobial activity and shown to inhibit the growth of MRSA in vitro.

A novel two-dimensional (2D) supramolecular organic framework (SOF) has been assembled, which was further used as a fluorescent chemosensor to detect picric acid with high selectivity and sensitivity.

ABC triblock copolymers bearing adenine- and thymine-functionalized external blocks self-assembled into long-range, ordered lamellar microphase-separated morphologies on non-patterned substrates.

An anthracene molecular probe has been synthesised and shown to target mephedrone, a stimulant drug from the cathinone class of new psychoactive substances (NPS).

A pyrrole derivative possessing two perfluorohexyl (C₆F₁₃) chains at the β-positions was synthesized. The significant electron-withdrawing properties of the β-perfluoroalkyl chains induced fascinating anion-binding behaviour.

Pillar[5]arene with one benzoquinone formed weak complex with a guest, while pillar[5]arene containing one hydroquinone strongly captured the guest.

[m]Bp-ExPn with a rigid and nanometer-sized cavity, as an extended version of pillar[n]arene by replacing 1,4-dimethoxybenzene monomers with biphenyl entities, was successfully designed and synthesized. Intriguingly, [m]Bp-ExPn possesses a wide array of potential applications in the purification of petrochemicals.

Oxatub[4]arene was found to be able to host a wide range of organic cations. This strong binding ability is believed to originate from its four interconvertible and deep-cavity conformers.

A G₄-quartet based hydrogel formed by self-assembly of borate esters of 5′-deoxy-5′-iodoguanosine (5′-IG 2) undergoes in situ cyclization to give 5′-deoxy-N3,5′-cycloguanosine (5′-cG 3). Formation of 5′-cG 3 causes self-destruction of the gel. This intramolecular cyclization can be used to release nucleoside analogs that have been pre-incorporated into the gel network.

Poly(2-isopropyl-2-oxazoline) (POx), a typical thermo-responsive polymer, was conjugated with a tetraphenylethene derivative, having aggregation induced emission behavior, towards the thermal control of their fluorescence emission.

Simple functionalised pyrene derivatives can achieve ratiometric sensing of heparin with the precise sensing mechanism depending on whether the sensor self-assembles into a multivalent ligand display.

Fluorescent, aqueous-soluble, crosslinked dendronized polyols (CDPs) are obtained through a sequential process involving ring-opening metathesis polymerization (ROMP), intra-chain ring-closing metathesis (RCM), and hydrolysis.

By inserting stimuli-responsive groups (azobenzene) in hetero-dimeric capsules, we are able to modify the equilibrium state of the system and the exchange between different host–guest assemblies in a reversible manner.