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The document is the contents list for an issue of the journal Chemical Communications. It includes articles on various topics such as AI-assisted chemistry research, modification strategies of lead halide perovskite nanocrystals, gold catalysis in quinoline synthesis, and rapid production of H2O2 in a photocatalyst suspension. The journal is published by The Royal Society of Chemistry and aims to connect the world with the chemical sciences. [Extracted from the article]

Taking advantage of the excellent host–guest complexation ability between an auxochrome (adamantane group) and CB[7], the fluorescence emission performance of dyes in water was effectively improved with the addition of two equivalents of CB[7], which provided an efficient method for increasing fluorescence intensity in aqueous environments. Furthermore, these dyes with the host were successfully used in cell imaging. [ABSTRACT FROM AUTHOR]

One colorimetric and one fluorescent‐indicator displacement assay (IDA) were studied to assess their interaction with methyl viologen (MV), an herbicide commercially known as paraquat. The host–guest complexes formed by cucurbit[7]uril (CB[7]) and the 4‐nitroaniline (NA) or Berberine (Be) dyes function as colorimetric‐ and fluorescent‐IDA for MV, respectively. The CB[7]@NA and CB[7]@Be complexes were characterized by UV–vis, fluorescence spectroscopy, and dynamic simulations. Isothermal titration calorimetry (ITC) experiments and dynamic simulations were employed to obtain thermodynamic data for the formation of the 1:1 inclusion complexes. Finally, NA is proposed as a reference colorimetric dye for determining CB[7]‐binding affinities using competitive host–guest titrations, and the fluorescent‐IDA as the best assay proposed, as it exhibits a high binding constant, a good detection limit of 2.7 × 10−6 mol L‐1, good linearity in the range from 4 × 10−6 mol L‐1 to 3.5 × 10−5 mol L‐1, in aqueous solution. [ABSTRACT FROM AUTHOR]

Using fluorescence spectroscopy, the two-photon absorption cross sections of aqueous solutions of the styryl dye trans-4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide (DASPI) and its inclusion complexes with cucurbit[n]urils (CB[n] n = 6–8) have been measured. A nonmonotonic dependence of the cross section on the excitation wavelength and on the cavitand cavity size has been revealed. Compared to the free dye, a sevenfold increase in the two-photon absorption cross section has been observed in DASPI inclusion complexes with CB[8] at an excitation wavelength of 980 nm. [ABSTRACT FROM AUTHOR]

Carbon nanomaterials doped with N and B could activate nearby carbon atoms to promote charge polarization through the synergistic coupling effect between N and B atoms, thus facilitating adsorption of O2 and weakening O−O bond to enhance oxygen reduction reaction. Herein, a simple and controllable self‐assembly strategy is applied to synthesize porous B, N co‐doped carbon‐based catalysts (BCN‐P), which employs the macrocyclic molecule cucurbit[7]uril (CB7) as nitrogen source, and 3D aromatic‐like closo‐[B12H12]2− as boron source. In addition, polystyrene microspheres are added to help introduce porous structure to expose more active sites. Benefitting from porous structures and the synergistic coupling effect between N and B atoms, BCN‐P has a high onset potential (Eonset=0.846 V) and half‐wave potential (E1/2=0.74 V) in alkaline media. The zinc‐air battery assembled with BCN‐P shows high operating voltage (1.42 V), peak power density (128.7 mW cm−2) and stable charge/discharge cycles, which is even comparable with Pt/C. [ABSTRACT FROM AUTHOR]

The highly strained, phenylene‐derived organic cages are typically regarded as very rigid entities, yet their deformation potential and supramolecular properties remain underexplored. Herein, we report a pliable conjugated phenylene nanocage by synergistically merging rigid and flexible building blocks. The anisotropic cage molecule contains branched phenylene chains capped by a calix[6]arene moiety, the delicate conformational changes of which endow the cage with a remarkably deformable cavity. When complexing with fullerene guests, the cage showcases excellent guest‐adaptivity, with its cavity volume capable of swelling by as much as 85 %. [ABSTRACT FROM AUTHOR]

The highly strained, phenylene‐derived organic cages are typically regarded as very rigid entities, yet their deformation potential and supramolecular properties remain underexplored. Herein, we report a pliable conjugated phenylene nanocage by synergistically merging rigid and flexible building blocks. The anisotropic cage molecule contains branched phenylene chains capped by a calix[6]arene moiety, the delicate conformational changes of which endow the cage with a remarkably deformable cavity. When complexing with fullerene guests, the cage showcases excellent guest‐adaptivity, with its cavity volume capable of swelling by as much as 85 %. [ABSTRACT FROM AUTHOR]

The water-soluble bromophenoxy-substituted naphthalimide derivative 1 and its copolymer P1 with acrylamide were synthesized and the photophysical properties of their host–guest complexes with cucurbit[8]uril (CB[8]) were studied. Notably, the host–guest complex CB[8]·1 showed long-lived RTP on filter paper and demonstrated a humidity response, making it suitable for use as an encryption ink. Furthermore, the solid powder of the host–guest complex between P1 and CB[8] exhibited a 4 s afterglow emission. [ABSTRACT FROM AUTHOR]

This study represents an advancement in the field of composite material engineering, focusing on the synthesis of composite materials derived from porous hydroxyapatite via surface modification employing cucurbit[n]urils, which are highly promising macrocyclic compounds. The surface modification procedure entailed the application of cucurbit[n]urils in an aqueous medium onto the hydroxyapatite surface. A comprehensive characterization of the resulting materials was undertaken, employing analytical techniques including infrared (IR) spectroscopy and scanning electron microscopy (SEM). Subsequently, the materials were subjected to rigorous evaluation for their hemolytic effect, anti-inflammatory properties, and cytotoxicity. Remarkably, the findings revealed a notable absence of typical hemolytic effects in materials incorporating surface-bound cucurbit[n]urils. This observation underscores the potential of these modified materials as biocompatible alternatives. Notably, this discovery presents a promising avenue for the fabrication of resilient and efficient biocomposites, offering a viable alternative to conventional approaches. Furthermore, these findings hint at the prospect of employing supramolecular strategies involving encapsulated cucurbit[n]urils in analogous processes. This suggests a novel direction for further research, potentially unlocking new frontiers in material engineering through the exploitation of supramolecular interactions. [ABSTRACT FROM AUTHOR]

Macrocyclic arenes show conformational adaptability, which allows host–guest complexations with the size‐matched guest molecules. However, their emission properties are often poor in the solid states due to the self‐absorption. Herein, we newly synthesized pillar[6]arene derivatives having alternate methylene and nitrogen bridging structures. Solvatochromic study reveals that the nitrogen‐embedding into the cyclic structures can strengthen the intramolecular charge transfer (CT) nature compared to that of the linear nitrogen‐bridged precursor. Owing to the large Stokes shift in the solid state, one of the nitrogen‐embedded pillar[6]arenes shows high absolute photoluminescence quantum yield (ΦPL=0.36). Furthermore, it displays a turn‐off sensing ability toward nitrobenzene (NB) vapor; a fluorescence quenching is observed when exposed to the NB vapor. From the structural analysis before and after the exposure of NB vapor, the amorphous nitrogen‐embedded pillar[6]arene efficiently co‐crystallize with NB and formed non‐emissive intermolecular CT complexes with NB. [ABSTRACT FROM AUTHOR]

Redox–active components are highly valuable in the construction of molecular devices. We combined two p‐phenylenediamines (p‐PDA) with a biphenyl (BiPhe) unit to prepare a supramolecular guest 4 consisting of three binding sites for cucurbit[7/8]uril (CBn) and/or cyclodextrins (CD). Supramolecular properties of 4 were investigated using NMR, UV‐vis, mass spectrometry and isothermal titration calorimetry. Our analysis revealed that 4 forms higher–order host–guest complexes, wherein a CD unit occupies the central BiPhe site, secured by two CBn units at the terminal p‐PDA sites. Additionally, 1 : 1 complexes with α‐CD and β‐CD, a 1 : 2 complex with γ‐CD and 2 : 1 complexes with CB7 and CB8 were identified. Through UV‐vis and cyclic voltammetry, redox processes leading to the formation of a stable, deep blue dication diradical of 4 are elucidated. Furthermore, it is demonstrated that CB7 selectively protects oxidised 4 from reduction in the presence of a reducing agent. The supramolecular and redox properties of the structural motif represented by 4 render it an interesting candidate for the construction of supramolecular devices. [ABSTRACT FROM AUTHOR]

Aiming to endow natural minerals with fast, high-sensitivity, and controllable smart light, humidity, solvent and temperature responsiveness, a novel ceramic clay and cucurbituril (CB) guest-host system (MVCB) inspired by nature was self-assembled and rearranged via an ingenious and simple design successfully. For the first time, the multi-functional MVCB not only displayed a high intelligent multi-stimuli responsiveness as light, humidity, solvent, and temperature switches, but also had multiple selective molecular recognition responses because of different organic vapor with CB and asymmetrical bilayer clay. For instance, due to the factors of guest-host and slow release, the average response speed of self-assembled shuffling the MVCB in methanol was as high as 108°/s compared with bilayer film without CB (20°/s). Besides, the MVCB exhibited controllable swift movement and was bending for grabbing three times its own weight. Moreover, the ultra-wide operating temperature of the MVCB from was ranging −196 to 300 °C under extreme condition. More interestingly, the MVCB presented a unique and compliable self-driven, smart switch, shape memory, environmental awareness and soft robotic gripper owing to the asymmetrical swelling and supramolecular of the CB. This work not only brings a simple, cost-effective, large-scale, and efficient strategy for multi-functionalized natural minerals materials, but also opens potential applications for intelligent response, extremely resistant substances, energy conversion and soft robotics. [ABSTRACT FROM AUTHOR]

The accumulation of organic micropollutants (OMP) in aquatic systems is a major societal problem that can be addressed by approaches including nanofiltration, flocculation, reverse osmosis and adsorptive methods using insoluble materials (e.g. activated carbon, MOFs, nanocomposites). More recently, polymeric versions of supramolecular hosts (e.g. cyclodextrins, calixarenes, pillararenes) have been investigated as OMP sequestrants. Herein, we report our study of the use of water insoluble dimethylcatechol walled acyclic cucurbit[n]uril (CB[n]) hosts as solid state sequestrants for a panel of five OMPs. A series of hosts (H1–H4) were synthesized by reaction of glycoluril oligomer (monomer–tetramer) with 3,6‐dimethylcatechol and fully characterized by spectroscopic means and x‐ray crystallography. The solid hosts sequester OMPs from water with removal efficiencies exceeding 90 % in some cases. The removal efficiencies of the new hosts parallel the known molecular recognition properties of analogous water soluble acyclic CB[n]. OMP uptake by solid host occurs rapidly (≈120 seconds). Head‐to‐head comparison with CB[6] in batch‐mode separation and DARCO activated carbon in flow‐through separation mode show that tetramer derived host (H4) performs very well under identical conditions. The work establishes insoluble acyclic CB[n]‐type receptors as a promising new platform for OMP sequestration. [ABSTRACT FROM AUTHOR]

Organic macrocyclic complexes composed of polyoxometalates (POMs) and cyclodextrins based on host–guest interactions have garnered significant attention. Herein, we report the assemblies by blending inorganic POMs and a complex macrocycle. Utilizing silver-coordinated bridge connections, four distinct POM-based silver-bisphosphine (Ag2dppp2) (dppp = 1,3-bis(diphenylphosphino)propane) macrocyclic hybrids: [Ag4(dppp)4(Mo8O26)] (1), {[Ag4(dppp)4(PW12O40)]NO3} (2), [Ag3(dppp)3(PMo12O40)] (3), and [Ag2(dppp)2(CH3CN)2(Mo6O19)] (4) have successfully been synthesized. The self-assemblies of hybrids involve sandwich and tubular structures that depend on the size, charge of POMs, anions and coordination solvent. Interactions of the silver-bisphosphine macrocycle and POMs in solution were further examined by 31P nuclear magnetic resonance (NMR) and cyclic voltammetry (CV). Dye adsorption behavior has been investigated for the structure–activity relationship of surface structures of the hybrids. [ABSTRACT FROM AUTHOR]

The document is the contents list for the journal "Chemical Communications" published in 2024. It includes a variety of articles on topics such as high-throughput continuous flow, continuous flow reactions in pharmaceuticals and fine chemicals, AI in computational chemistry, and various other topics in chemistry research. The journal is published by The Royal Society of Chemistry, a leading chemistry community. [Extracted from the article]

Herein, we report the thermal transitions and structural properties of poly(3,4-ethylenedioxythiophene/cucurbit[7]uril) pseudopolyrotaxane (PEDOT∙CB7-PS) and polyrotaxane (PEDOT∙CB7-PR) thin films compared with those of pristine PEDOT. The structural characteristics were investigated by using variable-temperature spectroscopic ellipsometry (VTSE), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and atomic force microscopy (AFM). VTSE and DSC results indicated the presence of an endothermic process and glass transition in the PEDOT∙CB7-PS and PEDOT∙CB7-PR thin films. X-ray diffraction of PEDOT∙CB7-PS and PEDOT∙CB7-PR powders displayed the presence of interchain π-π stacking revealing a characteristic arrangement of aromatic rings in the internal structure of the crystallites. AFM imaging of PEDOT∙CB7-PS and PEDOT∙CB7-PR thin films exhibited significant differences in the surface topographies compared with those of PEDOT. A high degree of crystallization was clearly visible on the surface of the PEDOT layer, whereas the PEDOT∙CB7-PS and PEDOT∙CB7-PR thin films exhibited more favorable surface parameters. Such significant differences identified in the surface morphology of the investigated layers can, therefore, be clearly associated with the presence of surrounding CB7 on PEDOT skeletons. [ABSTRACT FROM AUTHOR]

Coordination cages sustained by metal–ligand interactions feature polyhedral architectures and well-defined hollow structures, which have attracted significant attention in recent years due to a variety of structure-guided promising applications. Sulfonylcalix[4]arenes-based coordination cages, termed metal–organic supercontainers (MOSCs), that possess unique multi-pore architectures containing an endo cavity and multiple exo cavities, are emerging as a new family of coordination cages. The well-defined built-in multiple binding domains of MOSCs allow the efficient encapsulation of guest molecules, especially for drug delivery. Here, we critically discuss the design strategy, and, most importantly, the recent advances in research surrounding cavity-specified host–guest chemistry and biomedical applications of MOSCs. [ABSTRACT FROM AUTHOR]

A novel triphenylamine-based SOF was constructed, which can serve as superoxide radical generator to promote the oxidative hydroxylation of arylboronic acids under green light in water. [Display omitted] • A novel triphenylamine-based SOF was constructed based on the host–guest interaction. • The control of singlet oxygen and superoxide radical can be realized by using SOF as photosensitizers. • The monomer TP-3Py can effectively produce singlet oxygen (1O 2) and realize the photocatalytic oxidation of thioanisole in water. • The TP-SOF has the ability to generate superoxide anion radicals (O 2 •−) efficiently. • TP-SOF can be used for the promotion of the oxidative hydroxylation of arylboronic acids under green light in water. Supramolecular organic frameworks (SOFs) mostly require high-energy purple or blue light for photocatalytic reactions, while highly abundant and low-energy light systems have rarely been explored. Therefore, it is necessary to construct 2D SOFs for low-energy light-induced photocatalysis. This study describes the design and synthesis of a water-soluble two-dimensional (2D) supramolecular organic framework (TP-SOF) using the host–guest interaction between a triphenylamine derivative (TP-3Py) and cucurbit[8]uril (CB[8]). The formation of the 2D SOF can be attributed to the synergistic impact resulting from the orientated head-to-tail superposition mode between the vinylpyridine arms of TP-3Py and CB[8], which results in a significant redshift in the UV–vis absorption spectrum, especially displaying a strong absorption band in the green light region. The monomeric TP-3Py can effectively produce singlet oxygen (1O 2) and realize the photocatalytic oxidation of thioanisole in the aqueous solution. In comparison to monomeric TP-3Py, the confinement effect of CB[8] results in a notable enhancement in the production efficiency of superoxide anion radicals (O 2 •−), exhibiting promising prospects in the field of photocatalytic oxidation reaction, which facilitates the application of TP-SOF as a very efficient photosensitizer for the promotion of the oxidative hydroxylation of arylboronic acids under green light in the aqueous solution, giving a high yield of 91%. The present study not only presents a compelling illustration of photocatalysis utilizing a 2D SOF derived from triphenylamine, but also unveils promising avenues for the photocatalytic oxidation of SOF employing low-energy light systems. [ABSTRACT FROM AUTHOR]

Photoswitchable supramolecular self‐assemblies are promising candidates for intelligent recognition because of their noninvasive and spatial precision. However, the manipulation of the self‐assembly and disintegration of multicomponent mixtures with light of different wavelengths remain difficult. Here, an orthogonal three‐wavelength‐controlled two‐stage supramolecular self‐assembly consisting of two photoswitches, diarylethene, and protonated merocyanine is designed, mediated by supramolecular macrocyclic host. Owing to the reversible photo‐transformation of the switches, an optimized approach including three wavelengths irradiation and a thermal relaxation process is developed without mutual interference, realizing interconversion among four self‐assembled states. These self‐assemblies are photodeformable with reversibility, which can be operated in a cellular environment. Taking advantage of the photochromism in both absorption and fluorescence of these self‐assemblies in different behaviors, a visual pattern that can simultaneously display multiple hidden information under dual‐signal emission is created. This work signifies a promising strategy in improving the ability of information encryption and anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

Red phosphorus (RP) is an emerging visible‐light‐responsive photocatalyst, yet the rapid charge recombination has limited photocatalytic hydrogen production activity. In this work, a Z‐scheme heterostructure with RP nanolayer coated on high‐index (116) faceted anatase TiO2 nanoparticles (TiO2@RP) is designed and fabricated via chemical vapor deposition. Compared with pristine TiO2 and RP, the optimized TiO2@RP Z‐scheme heterostructure exhibits a significantly boosted photocatalytic activity for pure water splitting, with hydrogen evolution rate reaching 12.9 µmol·h−1, under simulated solar light irradiation. The strong interfacial interaction and staggered band alignment between (116) faceted TiO2 and RP result in the formation of built‐in electric field, which can drive the directional charge migration from the conduction band (CB) of TiO2 to the valance band (VB) of RP under light irradiation, with photoelectrons and holes of high redox ability maintained at the CB of RP and the VB of TiO2, respectively. This well‐designed heterostructure greatly promotes photogenerated charge separation and migration via a direct Z‐scheme charge transfer pathway. [ABSTRACT FROM AUTHOR]

Inspired by the drawstring structure in daily life, here we report the development of a drawstring‐mimetic supramolecular complex at the molecular scale. This complex consists of a rigid figure‐of‐eight macrocyclic host molecule and a flexible linear guest molecule which could interact through three‐point non‐covalent binding to form a highly selective and efficient host‐guest assembly. The complex not only resembles the drawstring structure, but also mimics the properties of a drawstring with regard to deformations under external forces. The supramolecular drawstring can be utilized as an interlocked crosslinker for poly(methyl acrylate), and the corresponding polymer samples exhibit comprehensive enhancement of macroscopic mechanical performance including stiffness, strength, and toughness. [ABSTRACT FROM AUTHOR]

Inspired by the drawstring structure in daily life, here we report the development of a drawstring‐mimetic supramolecular complex at the molecular scale. This complex consists of a rigid figure‐of‐eight macrocyclic host molecule and a flexible linear guest molecule which could interact through three‐point non‐covalent binding to form a highly selective and efficient host‐guest assembly. The complex not only resembles the drawstring structure, but also mimics the properties of a drawstring with regard to deformations under external forces. The supramolecular drawstring can be utilized as an interlocked crosslinker for poly(methyl acrylate), and the corresponding polymer samples exhibit comprehensive enhancement of macroscopic mechanical performance including stiffness, strength, and toughness. [ABSTRACT FROM AUTHOR]

Cigarette butts (CBs) are the most common type of beach litter worldwide and contain a complex mixture of chemicals. Given the recent interest in this emerging problem, it is important to assess the toxicity of CB leachates to a range of species from different regions, sensitivities, and ecological traits. We evaluated the waterborne toxicity of smoked CB to tropical invertebrates. Leachates were prepared in the laboratory and characterized for trace elements (Mn, Fe, Co, Ni, Cu, Zn, As, Cd, and Pb), ammonia nitrogen, and polycyclic aromatic hydrocarbons. Then a set of toxicity tests with marine invertebrates was performed as follows: the brine shrimp Artemia sp. (nontoxic); the amphipod Tiburonella viscana (median lethal concentration [LC50] of 0.038 CB/L); the tanaid Monokalliapseudes schubarti (LC50 of 0.126 CB/L); the copepods Tisbe biminiensis (median effect concentration [EC50] of 0.038 CB/L) and Nitokra sp. (EC50 of 0.009 CB/L); pluteus stage larvae of the sea urchin Echinometra lucunter (EC50 of 0.152 CB/L); the sand dollar Mellita quinquiesperforata (EC50 of 0.054 CB/L); and D‐stage larvae of the mussel Perna perna (EC50 of 0.005 CB/L). The predicted no‐effect concentration was estimated using species sensitivity distribution, producing a 5th percentile hazard concentration of 0.015 CB/L. This preliminary threshold allowed us to estimate the potential impact of a single CB to 67 L of seawater via leaching, contributing to the advancement of knowledge regarding the contamination, toxicity, and ecological risks of cigarette waste. Environ Toxicol Chem 2024;43:374–384. © 2023 SETAC [ABSTRACT FROM AUTHOR]

The effect of carbon-based additives on adhesives and potting compounds with regard to electrical conductivity and electromagnetic interference (EMI) shielding properties is of great interest. The increasing power of wireless systems and the ever-higher frequency bands place new demands on shielding technology. This publication gives an overview of the effect of carbon-based fillers on electrical conductivity, electromagnetic shielding properties, and the influence of different fillers and filler amounts on rheological behavior. This work focuses on carbon black (CB), recycled carbon fibers (rCF), carbon nanotubes (CNTs), and complex nanomaterials. Therefore, silicon samples with different fillers and filler amounts were prepared using a dual asymmetric centrifuge and a three-roll mill. It has been found that even with small filler amounts, the electromagnetic shielding properties were drastically raised. The filler content as well as the dispersion technique have a significant influence on most of the fillers. It has also been found that the complex viscosity is strongly influenced by the dispersion technique as well as by the choice and amount of filler. In the experiments carried out, shielding values of over 20 dB were achieved with several fillers, whereby even 43 dB were reached with complex, pre-crosslinked fillers. This signal reduction of up to 99.99% enables almost complete shielding of the related frequency. [ABSTRACT FROM AUTHOR]

Now that the chemistry of 1 : 1 host:guest complexes is well‐established, it is surprising to note that higher stoichiometry (oligomeric) complexes, especially those with excess host, remain largely unexplored. Yet, proteins tend to oligomerize, affording new functions for cell machinery. Here, we show that cucurbit[n]uril (CB[n]) macrocycles combined with symmetric, linear di‐viologens form unusual 3 : 2 host:guest complexes exhibiting remarkable dynamic properties, host self‐sorting, and external ring‐translocation. These results highlight the structural tunability of cucurbit[8]uril (CB[8]) based 3 : 2 host:guest complexes in water and their responsiveness toward several stimuli (chemicals, pH, redox). [ABSTRACT FROM AUTHOR]

Now that the chemistry of 1 : 1 host:guest complexes is well‐established, it is surprising to note that higher stoichiometry (oligomeric) complexes, especially those with excess host, remain largely unexplored. Yet, proteins tend to oligomerize, affording new functions for cell machinery. Here, we show that cucurbit[n]uril (CB[n]) macrocycles combined with symmetric, linear di‐viologens form unusual 3 : 2 host:guest complexes exhibiting remarkable dynamic properties, host self‐sorting, and external ring‐translocation. These results highlight the structural tunability of cucurbit[8]uril (CB[8]) based 3 : 2 host:guest complexes in water and their responsiveness toward several stimuli (chemicals, pH, redox). [ABSTRACT FROM AUTHOR]

Supramolecular systems may be used to stabilize otherwise unstable isomers to find alternative synthetic pathways. It has been reported that cucurbit[8]uril can stabilize trans-I and trans-II Cu II cyclam, whereas trans-III is the only non-substituted trans Cu II cyclam diastereoisomer found outside of the host molecule experimentally. Quantum chemistry methods can provide valuable insight into the intermolecular interactions involved in these inclusion complexes. All five possible trans diastereoisomers of Cu II cyclam were studied within the host molecule to calculate the interaction energy and free energy of association for each complex. The relative free energies of the five free cyclams confirm that trans-I and trans-II are the most energetically accessible diastereoisomers from the initial trans-III starting point. Energy decomposition analysis was used to identify the attractive and repulsive interactions between cyclam and cucurbit[8]uril and showed that trans-II encounters repulsive forces almost three times greater than trans-I, which may explain the 7:3 ratio of trans-I to trans-II within cucurbit[8]uril that occurs experimentally. Optimized complex geometries with trans-III, IV, and V show that the cyclams protrude out of cucurbit[8]uril, whereas trans-I and trans-II become more encapsulated and elongate the host, suggesting that the position of the cyclam is extremely important when forming non-covalent interactions. Our results agree with the experimental findings and provide greater insight into why the most stable isolated cyclam diastereoisomer, trans-III, does not form a complex. [ABSTRACT FROM AUTHOR]

The preparation of gold nanoparticles (AuNPs) from tetrachloroauric acid in the presence of tetrahydrothiophenocucurbit[n]uril (THTmQ[n]) has been effectively achieved in a microwave reactor. The reaction was performed in the presence of an excess of the tetrahydrothiopheno function in a partial reductant role, while the remainder formed AuNP-THTmQ[n] conjugates after the reduction was completed with formic acid. An affinity for the AuNPs by the THTmQ[n] was observed in the purification of the NPs via centrifugation, removal of the supernatant and resuspension of the conjugate. [ABSTRACT FROM AUTHOR]

Blue phosphorescent organic light-emitting diodes (B-PHOLEDs) using host–guest emissive layers have been studied, where the host and guest are 2,6-bis(3-(9H-carbazol-9-yl)phenyl)pyridine (26DCzPPy) and bis[2-(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium(III) (FIrPic), respectively. For the emissive layer with dye (guest) concentration of either 3 mol% or 10 mol%, there exist both the major and minor effective bandgaps. The major effective bandgap is governed by the lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) levels of 26DCzPPy, because the host molecules form a major dynamic-favorable channel to transport charge carriers. The minor effective bandgap is governed by the LUMO and HOMO levels of FIrPic, since the guest molecules form a minor thermodynamic-favorable channel to transport charge carriers. For the emissive layer with dye concentration of 22 mol%, the effective bandgap is determined by the LUMO and HOMO levels of FIrPic, because the guest molecules form a both dynamic- and thermodynamic-favorable channel to conduct charge carriers. Although the B-PHOLED with emissive layer of 26DCzPPy:FIrPic (3 mol%) shows wider exciton formation zone than the one with emissive layer of 26DCzPPy:FIrPic (10 mol%), the latter gives higher stability than the former, mostly attributed to the shorter triplet lifetime of 26DCzPPy:FIrPic (10 mol%) than that of 26DCzPPy:FIrPic (3 mol%). Due to both the larger effective bandgap and more charge carrier traps, the emissive layer of 26DCzPPy:FIrPic (10 mol%) enlarges the exciton formation zone and thereby increases device stability than that of 26DCzPPy:FIrPic (22 mol%), despite that the former has the longer triplet lifetime than the latter. The current research provides some novel insights into the correlation of dye-based nanoarchitectonics (dye concentration) with the device performance, helpful for the commercial development of B-PHOLEDs using host–guest emissive layers. [ABSTRACT FROM AUTHOR]

This review article focuses on the supramolecular assemblies fabricated through host-guest interaction using macrocycles such as cyclodextrins, calixarenes and cucurbiturils as hosts. Though several review articles have appeared on such host-guest assemblies having importance in controlled drug-delivery, fluorescence on-off sensors, catalysis etc., not much attention has been given to collect their potential applications in antibacterial activity. In this article we have mainly discussed the concepts, strategies and applications to enhance the antibacterial activity of different assemblies with some of the well-established antibacterial drugs/agents. The enhanced antibacterial activity of hydrogel, gelatin composite film, bismuth oxide nanoparticles and sanguinarine drug in the presence of cyclodextrins have been described in detail. The mechanism for the improved antibacterial activity of calixarene-capped nanoparticles, calixarene-complexed antibiotics and stimuli-responsive calixarene-based nanoassemblies for NO release was discussed. The enhanced photosensitizing effect of cucurbituril (CB) complexed porphyrins and their stimuli-responsive control over its antibacterial activity and the photothermal therapy has been elaborated. The effect of augmented antibacterial activity of CB-encapsulated drugs have also been given emphasis as they are promising for long-acting antibiotics. [ABSTRACT FROM AUTHOR]

Nowadays the use of hydrogels for biomedical purposes is increasing because of their interesting features that allow the development of targeted drug delivery systems. Herein, hydrogel based on Laponite® (Lap) clay mineral as gelator and cucurbit[6]uril (CB[6]) molecules were synthetized for the delivery of flufenamic acid (FFA) for potential topical application. Firstly, the interaction between CB[6] and FFA was assessed by UV‐vis spectroscopic measurements and molecular modeling calculations. Then, the obtained complex was used as filler for Lap hydrogel (Lap/CB[6]/FFA). The properties of the hydrogel in terms of viscosity and, self‐repair abilities were investigated; its morphology was imaged by scanning electron and polarized optical microscopies. Furthermore, the changes in the hydrodynamic radii and in the colloidal stability of CB[6]/Lap mixture were investigated in terms of translational diffusion from dynamic light scattering and ζ‐potential measurements. Finally, the kinetic in vitro release of FFA, from Lap/CB[6]/FFA hydrogel, was studied in a medium mimicking the pH of skin and the obtained results were discussed both by an experimental point of view and by molecular modeling calculations. [ABSTRACT FROM AUTHOR]

Resazurin (Alamar Blue, RZ) is a widely utilized fluorescent probe for biological sensing, whose fluorescent intensity can be modulated by changing its redox states; thereby, electrochemical reactivity of RZ is of significance when designing a sensing assay. Herein, we report novel two-way electrochemical reactivity modulation of RZ using host-guest complexation with rigid molecular containers cucurbit[n]uril (CBn, n = 7, 8). The complexation between CBn and RZ is confirmed by 1H NMR measurements and supported by computational simulation, and the binding constants are determined via UV-vis titration. Notably, the voltametric data highlights that the redox reactivity of RZ can be activated or deactivated upon encapsulation by CB8 or CB7, respectively. This two-way reactivity modulation is hypothesized to be mediated by the difference in cavity volume that favors or hinders the approach of water molecules to the encapsulated reaction center during the reduction process. Despite the similar cavity size to CB, molecular containers such as cyclodextrins (CDs) exhibit considerably weaker modulation effects. Our approach can potentially be applied to other redox processes that involve proton transfer, and open new possibilities in supramolecular electrochemistry. [ABSTRACT FROM AUTHOR]

Light‐driven multicolor supramolecular systems mainly rely on the doping of dyes or a photo‐reaction to produce unidirectional luminescence. Herein, we use visible light to drive the bidirectional reversible multicolor supramolecular shuttle from blue to green, white, yellow, up to orange by simple encapsulation of spiropyran‐modified cyanostilbene (BCNMC) by the macrocyclic cucurbit[8]uril (CB[8]) monomer. The resultant host–guest complex displayed enhanced fluorescence properties, i.e. the multicolor fluorescence shuttle changed from blue to orange in the dark within 2 hours and reverted to the original state upon visible light irradiation for 30 s. Benefiting from the sensitivity of the spiropyran moiety to light, it can spontaneously isomerize from the ring‐opened state to a ring‐closed isomer in aqueous solution, and this photo‐isomerization reaction is a reversible process under visible light irradiation, leading to the multicolor luminescence supramolecular shuttle as a result of intramolecular energy transfer. In addition, the light also drove the reversible conversion of the topological morphology of the host–guest complex from two‐dimensional nanoplatelets to nanospheres. Different from the widely reported molecular rotaxane "shuttle", the spiropyran supramolecular shuttle confined in the macrocyclic host CB[8] not only modulated a reversible topological morphology by light but also exhibited multicolor luminescence, which was successfully applied in programmed and rewritable information encryption. [ABSTRACT FROM AUTHOR]

Light‐driven multicolor supramolecular systems mainly rely on the doping of dyes or a photo‐reaction to produce unidirectional luminescence. Herein, we use visible light to drive the bidirectional reversible multicolor supramolecular shuttle from blue to green, white, yellow, up to orange by simple encapsulation of spiropyran‐modified cyanostilbene (BCNMC) by the macrocyclic cucurbit[8]uril (CB[8]) monomer. The resultant host–guest complex displayed enhanced fluorescence properties, i.e. the multicolor fluorescence shuttle changed from blue to orange in the dark within 2 hours and reverted to the original state upon visible light irradiation for 30 s. Benefiting from the sensitivity of the spiropyran moiety to light, it can spontaneously isomerize from the ring‐opened state to a ring‐closed isomer in aqueous solution, and this photo‐isomerization reaction is a reversible process under visible light irradiation, leading to the multicolor luminescence supramolecular shuttle as a result of intramolecular energy transfer. In addition, the light also drove the reversible conversion of the topological morphology of the host–guest complex from two‐dimensional nanoplatelets to nanospheres. Different from the widely reported molecular rotaxane "shuttle", the spiropyran supramolecular shuttle confined in the macrocyclic host CB[8] not only modulated a reversible topological morphology by light but also exhibited multicolor luminescence, which was successfully applied in programmed and rewritable information encryption. [ABSTRACT FROM AUTHOR]

The family of cucurbiturils (CBs), the unique pumpkin-shaped macrocycles, has received great attention over the past four decades owing to their remarkable recognition properties. They have found diverse applications including biosensing and drug delivery technologies. The cucurbituril complexation of guest molecules can modulate their pKas, improve their solubility in aqueous solution, and reduce the adverse effects of the drugs, as well as enhance the stability and/or enable targeted delivery of the drug molecule. Employing twelve cationic styryl dyes with N-methyl- and N-phenylpiperazine functionality as probes, we attempted to understand the factors that govern the host–guest complexation of such molecules within CB[7] and CB[8] host systems. Various key factors determining the process were recognized, such as the pH and dielectric constant of the medium, the cavity size of the host, the chemical characteristics of the substituents in the guest entity, and the presence/absence of metal cations. The presented results add to our understanding (at the molecular level) of the mechanism of encapsulation of styryl dyes by cucurbiturils, thus shedding new light on various aspects of the intriguing complexation chemistry and the underlying recognition processes. [ABSTRACT FROM AUTHOR]

Ring translocation switches and shuttles featuring a macrocycle (or a ring molecule) navigating between two or more stations continue to attract attention. While the vast majority of these systems are developed in organic solvents, the cucurbituril (CB) macrocycles are ideally suited to prepare such systems in water. Indeed, their stability and their relatively high affinity for relevant guest molecules are key attributes toward translating the progresses made in organic solvents, into water. This concept article summarizes the findings, key advances and multiple possibilities offered by CBs toward advanced molecular switches and shuttles in water. [ABSTRACT FROM AUTHOR]

Calixarenes are "chalice like" phenol-based macrocycles that are one of the most fascinating studied scaffolds in supramolecular chemistry. Their preorganized nonpolar cavities and ion binding sites, and their well-defined conformations all lay important foundations for forming host–guest complexes. Conjugation of calixarene scaffolds with various fluorophores at either upper or lower rims has led to the development of smart fluorescent probes for inorganic molecules or ions, aliphatic or aromatic compounds, biomolecules, temperature and hypoxia, even multi-component traditional Chinese medicine (TCM). Moreover, significant advancements have been made for biological applications. This review critically summarizes the recent advances made in these areas. [ABSTRACT FROM AUTHOR]

The complexation of the styryl dyes 1-ethyl-4-{(E)-2-[4-(methylthio)phenyl]vinyl}pyridinium perchlorate (1) and 1-ethyl-4-[(E)-2-(4-methoxyphenyl)vinyl]pyridinium perchlorate (2) with cucurbit[6]uril (CB[6]) in aqueous solutions has been studied using steady-state and time-resolved fluorescence spectroscopy. The binding constant of the 1 : 1 inclusion complex of 1 and CB[6] is logK = 6.28, with fluorescence increasing threefold, and the 1 : 1 complex of 2 and CB[6] has logK = 5.99, with fluorescence increasing by four times. The fluorescence decay of the dyes and their complexes has two characteristic times, the short one of ~2–3 ps and the long one on the order of ten picoseconds. In inclusion complexes, the latter is greater than in the free dyes. The mechanism of photobleaching of the studied dyes and their complexes with cucurbit[6]uril is considered. [ABSTRACT FROM AUTHOR]

In this present investigation, a novel series of composite materials based on porous inorganic compounds—hydroxyapatite and diatomite—have been innovatively formulated for the first time through surface modification employing the promising macromolecular compound, bambus[6]uril. The process entailed the application of a bambus[6]uril dispersion in water onto the surfaces of hydroxyapatite and diatomite. Extensive characterization was carried out, involving IR spectroscopy and SEM. The materials underwent assessment for hemolytic effects and plasma protein adsorption. The results revealed that materials containing surface-bound bambus[6]uril did not demonstrate inherent hemolytic effects, laying a robust groundwork for their use as biocompatible materials. These findings hold significant promise as an alternative pathway for the development of durable and efficient bio-composites, potentially unveiling supramolecular strategies incorporating encapsulated bambus[6]urils in analogous processes. [ABSTRACT FROM AUTHOR]

Nowadays, functionalized cucurbit[n]urils are considered one of the most important examples of macromolecules and have attracted a lot of attention due to their potential applications in several sectors. In the present work monomethyl‐cucurbit[7]uril (3) was synthesized for the first time through facile synthetic route with high purity form by the reaction of monomethylglycoluril (3a‐methyltetrahydroimidazo[4,5‐d]imidazole‐2,5(1H,3H)‐dione) with glycoluril (tetrahydroimidazo[4,5‐d]imidazole‐2,5(1H,3H)‐dione) in the ratio of 1:6, respectively, and formaldehyde in the presence of hydrochloric acid as a catalyst for 24 h at 95°C through Mannich reaction. Moreover, dimethyl‐cucurbit[7]uril (5) was successfully synthesized through the reaction of dimethylglycoluril (3a,6a‐dimethyltetrahydroimidazo[4,5‐d]imidazole‐2,5(1H,3H)‐dione) with glycoluril (tetrahydroimidazo[4,5‐d]imidazole‐2,5(1H,3H)‐dione), following the same procedure as for the monomethyl‐cucurbit[7]uril. The chemical structures of the obtained compounds were established by mass spectrometry, NMR spectroscopy, and quantum‐chemical calculations. [ABSTRACT FROM AUTHOR]

[Display omitted] In the present work, we have designed and synthesized a triphenylamine modified cyanophenylenevinylene derivative (TPCI), which can self-assembly with cucurbit[6]uril (CB[6]) and cucurbit[8]uril (CB[8]) through host-guest interactions to form supramolecular complexes (TPCI-CB[6]) and supramolecular polymers (TPCI-CB[8]) in the aqueous solution. The supramolecular assemblies of TPCI-CB[6] and TPCI-CB[8] not only exhibited high singlet oxygen (1O 2) production efficiency as photosensitizers, but also realized the application in the construction of artificial light-harvesting systems due to the excellent fluorescence properties in the aqueous solution. The production efficiency of 1O 2 has been effectively improved after the addition of CB[6] and CB[8] for TPCI, which were applied as efficient photosensitizers in the photooxidation reactions of thioanisole and its derivatives with the highest yield of 98% in the aqueous solution. The excellent fluorescence properties of TPCI-CB[6] and TPCI-CB[8] can be used as energy donors in artificial light-harvesting systems with energy acceptors sulforhodamine 101 (SR101) and cyanine dye 5 (Cy5), in which one-step energy transfer processes of TPCI-CB[6]+SR101 and TPCI-CB[8]+Cy5, and a two-step sequential energy transfer process of TPCI-CB[6]+SR101+Cy5 were constructed to simulate the natural photosynthesis system. [ABSTRACT FROM AUTHOR]

Brain-Derived Neurotrophic Factor (BDNF) is a neurotrophin gene family gene that encodes proteins vital for the growth, maintenance, and survival of neurons in the nervous system. The study aimed to screen natural compounds against BDNF variant (V66M), which affects memory, cognition, and mood regulation. BDNF variant (V66M) as a target structure was selected, and Vitamin D, Curcumin, Vitamin C, and Quercetin as ligands structures were taken from PubChem database. Multiple tools like AUTODOCK VINA, BIOVIA discovery studio, PyMOL, CB-dock, IMOD server, Swiss ADEMT, and Swiss predict ligands target were used to analyze binding energy, interaction, stability, toxicity, and visualize BDNF-ligand complexes. Compounds Vitamin D3, Curcumin, Vitamin C, and Quercetin with binding energies values of − 5.5, − 6.1, − 4.5, and − 6.7 kj/mol, respectively, were selected. The ligands bind to the active sites of the BDNF variant (V66M) via hydrophobic bonds, hydrogen bonds, and electrostatic interactions. Furthermore, ADMET analysis of the ligands revealed they exhibited sound pharmacokinetic and toxicity profiles. In addition, an MD simulation study showed that the most active ligand bound favorably and dynamically to the target protein, and protein–ligand complex stability was determined. The finding of this research could provide an excellent platform for discovering and rationalizing novel drugs against stress related to BDNF (V66M). Docking, preclinical drug testing and MD simulation results suggest Quercetin as a more potent BDNF variant (V66M) inhibitor and forming a more structurally stable complex. [ABSTRACT FROM AUTHOR]

Pillar[n]arenes are symmetrical macrocyclic compounds composed of benzene panels with para‐methylene linkages. Each panel usually exhibits planar chirality and prefers chirality‐aligned states. Because of this feature, pillar[n]arenes are attractive scaffolds for chiroptical materials that are easy to prepare and optically resolve and show intense circular dichroism (CD) signals. In addition, rotation of the panels endows the chirality of pillar[n]arenes with a dynamic nature. The chirality in tubular oligomers and supramolecular assemblies sometimes show time‐ and procedure‐dependent alignment phenomena. Furthermore, the CD signals of some pillar[n]arenes respond to the addition of chiral guests when their dynamic chirality is coupled with host–guest properties. By using diastereomeric pillar[n]arenes with additional chiral structures, the response can also be caused by achiral guests and changes of the environment, providing molecular sensors. [ABSTRACT FROM AUTHOR]

Pillar[n]arenes are symmetrical macrocyclic compounds composed of benzene panels with para‐methylene linkages. Each panel usually exhibits planar chirality and prefers chirality‐aligned states. Because of this feature, pillar[n]arenes are attractive scaffolds for chiroptical materials that are easy to prepare and optically resolve and show intense circular dichroism (CD) signals. In addition, rotation of the panels endows the chirality of pillar[n]arenes with a dynamic nature. The chirality in tubular oligomers and supramolecular assemblies sometimes show time‐ and procedure‐dependent alignment phenomena. Furthermore, the CD signals of some pillar[n]arenes respond to the addition of chiral guests when their dynamic chirality is coupled with host–guest properties. By using diastereomeric pillar[n]arenes with additional chiral structures, the response can also be caused by achiral guests and changes of the environment, providing molecular sensors. [ABSTRACT FROM AUTHOR]

Due to intrinsic fluorescence behavior, and the environment‐dependent excited‐state intramolecular proton transfer (ESIPT) process, makes special attention towards flavonoids for conducting photophysical study. The binding of fisetin, morin hydrate, and quercetin with macrocyclic molecule Cucurbit[7]urils (CB[7]) has been studied using different spectroscopic methods. The changes in the thermodynamic parameters during complex formation between the flavonoids with CB[7] are estimated by an isothermal titration calorimetry study. From the spectroscopic measurement, we have seen that in the presence of CB[7], flavonoids show the ESIPT process and the prototropic equilibrium is present between different forms of flavonoids. The isothermal titration calorimetry study shows that the complex formation between these flavonoids with CB[7] spontaneously takes place at room temperature, which is an endothermic process. [ABSTRACT FROM AUTHOR]

A triazine pyridinium derivative (TAZpy) was encapsulated into the cavity of a cucurbit[7]uril and further assembled with sulfonatocalix[4]-arene, hyaluronic acid and commercial dyes, which not only achieved fluorescence cascade enhancement and an effective FRET process based on macrocyclic confinement, but was also applied in two-photon NIR targeted cell imaging. [ABSTRACT FROM AUTHOR]

3D hydrogel structures fabricated by two‐photon polymerization (TPP) have become attractive in biomedical fields. Generally, conventional organic solvents are toxic and the residues left in the fabricated 3D structures are harmful to cells. Hence, anion ionic carbazole‐based water‐soluble two‐photon initiator (TPI) 3,6‐bis[2‐(1‐methylpyridinium)vinyl]‐9‐methylcarbazole ditosylate (BT) is proposed to construct arbitrary 3D hydrogel structures. Cucurbit[7]uril (CB7) and BT form a host‐guest complex (CB7/BT) with a binding ratio of 1:1, which further improves the water solubility, biocompatibility and nonlinear absorption property of TPI. A water‐soluble photoresist consisting of photoinitiator CB7/BT and monomer poly(ethylene glycol) diacrylate is prepared to explore the TPP fabrication capacity. The electron paramagnetic resonance measurement shows that CB7/BT initiates photopolymerization by alkyl radicals. The laser threshold power of the photoresist is 6.3 mW and the feature size is 127 nm in TPP at 780 nm. The initiator with p‐toluenesulfonate anion exhibits higher binding energy, larger two‐photon absorption cross‐section and two‐photon fabrication resolution compared with the previous work using iodide as an anion, indicating a promising way to improve the fabrication capacity of water‐soluble TPI through changing the anion ionic group. The proposed strategy will provide high potential for the further application in the biomedical field. [ABSTRACT FROM AUTHOR]

Chiral induction by natural biomolecules can reveal the indispensable role of chiral structures in life and can be used to develop the chirality‐sensing biomolecular recognition. Here, we present the synthesis and characterization of an achiral supramolecular organic framework (SOF‐1) constructed from cucurbit[8]uril (CB[8]) and hexaphenylbenzene (HPB) derivative (1) in water. Due to the propeller‐like rotational chiral conformation of HPB units and the specific recognition properties of CB[8], SOF‐1 demonstrates chiral adaptive induction in water when interacting with the N‐terminal Trp‐/Phe‐containing dipeptides including L‐TrpX and L‐PheX (X is an amino acid residue), respectively, exhibiting contrasting circular dichroism (CD) and circularly polarized luminescence (CPL) spectra. Consequently, SOF‐1 has been developed as a supramolecular host and chiroptical sensor capable of recognizing and distinguishing the sequence‐opposite Trp‐/Phe‐containing dipeptide pairs including L‐TrpX/L‐XTrp and L‐PheX/L‐XPhe based on the sequence‐selective CD responses. [ABSTRACT FROM AUTHOR]

Chiral induction by natural biomolecules can reveal the indispensable role of chiral structures in life and can be used to develop the chirality‐sensing biomolecular recognition. Here, we present the synthesis and characterization of an achiral supramolecular organic framework (SOF‐1) constructed from cucurbit[8]uril (CB[8]) and hexaphenylbenzene (HPB) derivative (1) in water. Due to the propeller‐like rotational chiral conformation of HPB units and the specific recognition properties of CB[8], SOF‐1 demonstrates chiral adaptive induction in water when interacting with the N‐terminal Trp‐/Phe‐containing dipeptides including L‐TrpX and L‐PheX (X is an amino acid residue), respectively, exhibiting contrasting circular dichroism (CD) and circularly polarized luminescence (CPL) spectra. Consequently, SOF‐1 has been developed as a supramolecular host and chiroptical sensor capable of recognizing and distinguishing the sequence‐opposite Trp‐/Phe‐containing dipeptide pairs including L‐TrpX/L‐XTrp and L‐PheX/L‐XPhe based on the sequence‐selective CD responses. [ABSTRACT FROM AUTHOR]