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Dihydroxy-based polar organic cages (DIHO-cages) are reported to selectively separate toluene with 99.5% purity from an equimolar toluene/pyridine mixture, resulting in subsequent superior purification of pyridine. The efficient separation and purification, enhanced by strong and multiple host/guest C–H⋯O interactions between the cage and toluene, showcases DIHO-cages as a suitable candidate for the remarkable separation of such azeotropes on an industrial scale. [ABSTRACT FROM AUTHOR]

The discovery of safe platforms that can circumvent the endocytic pathway is of great significance for biological therapeutics that are usually degraded during endocytosis. Here we show that a self‐assembled and dynamic macrocycle can passively diffuse through the cell membrane and deliver a broad range of biologics, including proteins, CRISPR Cas9, and ssDNA, directly to the cytosol while retaining their bioactivity. Cell‐penetrating macrocycle CPM can be easily prepared from the room temperature condensation of diketopyrrolopyrrole lactams with diamines. We attribute the high cellular permeability of CPM to its amphiphilic nature and chameleonic properties. It adopts conformations that partially bury polar groups and expose hydrophobic side chains, thus self‐assembling into micellar‐like structures. Its superior fluorescence makes CPM trackable inside cells where it follows the endomembrane system. CPM outperformed commercial reagents for biologics delivery and showed high RNA knockdown efficiency of CRISPR Cas9. We envisage that this macrocycle will be an ideal starting point to design and synthesize biomimetic macrocyclic tags that can readily facilitate the interaction and uptake of biomolecules and overcome endosomal digestion. [ABSTRACT FROM AUTHOR]

Trianglimine (TI) and trianglamine (TA) macrocycles offer an efficient adsorptive molecular sieving strategy to separate toluene (Tol) from an equimolar mixture of Tol and methylcyclohexane (MCH) with 98.3% and 96.4% selectivity, respectively. Selective separation is achieved through the intrinsic cavity or extrinsic channel within the crystalline molecular absorbents, driven by C–H⋯π and π⋯π interactions. Moreover, TI and TA exhibit exceptional recyclability, highlighting their potential for sustainable chemical separation processes. [ABSTRACT FROM AUTHOR]

Porous molecular sorbents have excellent selectivity towards hydrocarbon separation with energy saving techniques. However, to realize commercialization, molecular sieving processes should be faster and more efficient compared to extended frameworks. In this work, we show that utilizing fluorine to improve the hydrophobic profile of leaning pillararenes affords a substantial kinetic selective adsorption of benzene over cyclohexane (20 : 1 for benzene). The crystal structure shows a porous macrocycle that acts as a perfect match for benzene in both the intrinsic and extrinsic cavities with strong interactions in the solid state. The fluorinated leaning pillararene surpasses all reported organic molecular sieves and is comparable to the extended metal–organic frameworks that were previously employed for this separation such as UIO‐66. Most importantly, this sieving system outperformed the well‐known zeolitic imidazolate frameworks under low pressure, which opens the door to new generations of molecular sieves that can compete with extended frameworks for more sustainable hydrocarbon separation. [ABSTRACT FROM AUTHOR]

"Frontiers in Chemistry: Rising Stars 2022" is a collection of research articles and reviews that highlights the work of emerging researchers in the field of chemistry. The publication features a diverse range of topics, including analytical chemistry, medicinal chemistry, and organic chemistry. The articles cover various innovative research findings and insights, contributing to the current knowledge in chemistry and paving the way for future discoveries. This compilation provides a platform for these promising scientists to share their work and acknowledges their potential to become future leaders in the field. [Extracted from the article]

The fabrication of smart materials, which can efficiently mimic biological systems through the introduction of soft components, is of great importance in the emerging fields of sensors and actuators. Herein, a smart composite film that can mechanically respond to vapors trigger then readily restores its original shape upon the removal of the stimuli is reported. This actuating composite film was prepared by mixing the highly elastic poly (vinylidene fluoride) (PVDF) polymer with the flexible and crystalline organic cages (Oba‐cage) at variable concentrations. The mechanism of the mechanical response could be accurately recorded due to the ordered cage crystals. This work highlights the importance of designing smart materials at the molecular level to precisely control the response or reaction upon the introduction of different triggers, which can ultimately lead to a monumental leap in the field of soft robotics. [ABSTRACT FROM AUTHOR]

Adenylyl cyclases (ACs) and their catalytic product cAMP are regulatory components of many plant responses. Here, we show that an amino acid search motif based on annotated adenylate cyclases (ACs) identifies 12 unique Arabidopsis thaliana candidate ACs, four of which have a role in the biosynthesis of the stress hormone abscisic acid (ABA). One of these, the 9-cis-epoxycarotenoid dioxygenase (NCED3 and At3g14440), was identified by sequence and structural analysis as a putative AC and then tested experimentally with two different methods. Given that the in vitro activity is low (fmoles cAMP pmol−1 protein min−1), but highly reproducible, we term the enzyme a crypto-AC. Our results are consistent with a role for ACs with low activities in multi-domain moonlighting proteins that have at least one other distinct molecular function, such as catalysis or ion channel activation. We propose that crypto-ACs be examined from the perspective that considers their low activities as an innate feature of regulatory ACs embedded within multi-domain moonlighting proteins. It is therefore conceivable that crypto-ACs form integral components of complex plant proteins participating in intra-molecular regulatory mechanisms, and in this case, potentially linking cAMP to ABA synthesis. [ABSTRACT FROM AUTHOR]

Developing the competence of molecular sorbents for energy‐saving applications, such as C8 separations, requires efficient, stable, scalable, and easily recyclable materials that can readily transition to commercial implementation. Herein, we report an azobenzene‐based cage for the selective separation of p‐xylene isomer across a range of C8 isomers in both vapor and liquid states with selectivity that is higher than the reported all‐organic sorbents. The crystal structure shows non‐porous cages that are separated by p‐xylene molecules through selective CH–π interactions between the azo bonds and the methyl hydrogen atoms of the xylene molecules. This cage is stable in solution and can be regenerated directly under vacuum to be used in multiple cycles. We envisage that this work will promote the investigation of the azo bond as well as guest‐induced crystal‐to‐crystal phase transition in non‐porous organic solids for energy‐intensive separations. [ABSTRACT FROM AUTHOR]

Efficient and energy‐saving separation of benzene isomers bearing a diverse range of functional groups is a great challenge due to their overlapping physicochemical properties. Here, we report the successfully use of a water‐soluble pillar[5]arene (WP5) as a multifunctional material for the separation and detection of meta/ortho‐substituted benzene isomers in water. A liquid‐liquid extraction strategy was used for the separation of these benzene isomers based on their different affinity for WP5 in water. The selectivities for the meta over the ortho isomer for xylenes, chlorotoluene, and bromotoluene was 88.6 %, 88.3 %, and 95.0 % respectively, in one extraction cycle. Furthermore, a fluorescence indicator system based on WP5 and a fluorescent dye molecule (10‐methylacridinium, D) was adopted and exhibited significant fluorescence and optical discrimination upon the addition of meta‐ compared to ortho‐xylene, which implies that a simple "turn‐on" detection can be performed prior to engaging in the separation process. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis of a new class of functional silver nanoclusters (AgNCs) capped with pillar[5]arene (P5)‐based host ligands. These NCs are readily prepared through direct synthesis or ligand exchange synthesis and are stable at room temperature for over 4 months. The pillar[5]arene‐stabilized NCs (Ag29(LA‐P5)12(TPP)2) endorse reversible host–guest interactions with neutral alkylamines and cationic quaternary ammonium guests. This results in the formation of spherical assemblies with unparalleled changes in their optical properties including an astonishing circa 2000‐fold luminescence enhancement. This is the highest luminescence enhancement ratio reported so far for such atomically precise NCs. Our synthetic protocol paves the way for the preparation of a new generation of metal nanoclusters protected by macrocyclic ligands with molecular recognition and selectivity toward specific guests. [ABSTRACT FROM AUTHOR]

Histidine-dialkoxyanthracene (HDA) was synthesised as a turn off type fluorescent sensor for fast and sensitive detection of mercury ions (Hg2+) in aqueous media. The two histidine moieties act as ‘claws’ to selectively complex Hg2+. The binding ratio of HDA to Hg2+was 1:1 (metal-to-ligand ratio). The association constant for Hg2+towards the receptor HDA obtained from Benesi–Hildebrand plot was found to be 3.22 × 104 M−1with detection limit as low as 4.7 nM (0.94 μg/L). [ABSTRACT FROM AUTHOR]

Optimized and sensitive biomarker detection has recently been shown to have a critical impact on quality of diagnosis and medical care options. In this research study, polyoxometalate-γ-cyclodextrin metal−organic framework (POM–γCD MOF) was utilized as an electrocatalyst to fabricate highly selective sensors to detect in-situ released dopamine. The POM–γCD MOF produced multiple modes of signals for dopamine including electrochemical, colorimetric, and smartphone read-outs. Real-time quantitative monitoring of SH-SY5Y neuroblastoma cellular dopamine production was successfully demonstrated under various stimuli at different time intervals. The POM-CD MOF sensor and linear regression model were used to develop a smartphone read-out platform, which converts dopamine visual signals to digital signals within a few seconds. Ultimately, POM–γCD MOFs can play a significant role in the diagnosis and treatment of various diseases that involve dopamine as a significant biomarker. [ABSTRACT FROM AUTHOR]

Supramolecular self-assembly of histidine-capped-dialkoxy-anthracene (HDA) results in the formation of light-responsive nanostructures. Single-crystal X-ray diffraction analysis of HDA shows two types of hydrogen bonding. The first hydrogen bond is established between the imidazole moieties while the second involves the oxygen atom of one amide group and the hydrogen atom of a second amide group. When protonated in acidic aqueous media, HDA successfully complexes siRNA yielding spherical nanostructures. This biocompatible platform controllably delivers siRNA with high efficacy upon visible-light irradiation leading up to 90% of gene silencing in live cells. [ABSTRACT FROM AUTHOR]

Colloidosome capsules possess the potential for the encapsulation and release of molecular and macromolecular cargos. However, the stabilization of the colloidosome shell usually requires an additional covalent crosslinking which irreversibly seals the capsules, and greatly limits their applications in large-cargos release. Herein we report nanoscaled colloidosomes designed by the electrostatic assembly of organosilica nanoparticles (NPs) with oppositely charged surfaces (rather than covalent bonds), arising from different contents of a bridged nitrophenylene-alkoxysilane [NB; 3-nitro- N-(3-(triethoxysilyl)propyl)-4-(((3-(triethoxysilyl)propyl)-amino)methyl)benzamid] derivative in the silica. The surface charge of the positively charged NPs was reversed by light irradiation because of a photoreaction in the NB moieties, which impacted the electrostatic interactions between NPs and disassembled the colloidosome nanosystems. This design was successfully applied for the encapsulation and light-triggered release of cargos. [ABSTRACT FROM AUTHOR]

Functional polymeric membranes are widely used to adjust and control the diffusion of molecules. Herein, photosensitive poly(hydroxycinnamic acid) (PHCA) microspheres, which were fabricated by an emulsification solvent-evaporation method, were embedded into an ethyl cellulose matrix to fabricate composite membranes with a photo-tunable property. The photoreaction of PHCA is based on the [2 + 2] cycloaddition of cinnamic moieties upon irradiation with 365 nm light. Intra-particle crosslinking in PHCA microspheres was confirmed in the solution phase, while inter-particle crosslinking between adjacent PHCA microspheres dominated the solid membrane phase. The inter-particle crosslinking turned down the permeability of the composite membranes by 74%. To prove the applicability of the designed system, the composite membrane was coated on a model drug reservoir tablet. Upon irradiating the tablet with UV light, the original permeability decreased by 57%, and consequently the diffusion rate of the cargo (Rhodamine B) from the tablet slowed down. Most importantly, the tablet showed sustained release for over 10 days. This controllability can be further tuned by adjusting the membrane thickness. Composite membranes showed excellent processing reproducibility together with consistent mechanical properties. These results demonstrate that the incorporation of photosensitive PHCA microspheres in polymeric membranes provides a promising photo-tunable material for different applications including coating and separation. [ABSTRACT FROM AUTHOR]

Polystyrene-block-polyvinylpyridine (PS-b-P4VP) polypseudorotaxanes with cucurbit[7]urils (CB[7]) were prepared from water soluble PS-b-P4VPH+ polymer and CB[7] in aqueous solution at room temperature. At acidic and neutral pH, the pyridinium block of PS-b-P4VP is protonated (PS-b-P4VPH+) pushing CB[7] to preferably host the P4VP block. At basic pH (pH 8), P4VP is not charged and thus is not able to strongly complex CB[7]. This phenomenon was verified further by monitoring the release of pyrene, a hydrophobic cargo model, from a PS-b-P4VPH+/CB[7] micellar membrane. Release study of UV active pyrene from the membrane at different pH values revealed that the system is only operational under basic conditions and that the host-guest interaction of CB[7] with P4VPH+ significantly slows down cargo release. [ABSTRACT FROM AUTHOR]

Metal-free fullerene (C60) was found to be an effective catalyst for the reduction of azo groups in basic aqueous solution under UV irradiation in the presence of NaBH4. Use of NaBH4 by itself is not sufficient to reduce the azo dyes without the assistance of a metal catalyst such as Pd and Ag. Experimental and theoretical results suggest that C60 catalyzes this reaction by using its vacant orbital to accept the electron in the bonding orbital of azo dyes, which leads to the activation of the NN bond. UV irradiation increases the ability of C60 to interact with electron-donor moieties in azo dyes. [ABSTRACT FROM AUTHOR]

Nanodiamond (ND) and its derivatives have been widely used for drug, protein and gene delivery. Herein, experimental and theoretical methods have been combined to investigate the effect of pH on the delivery of doxorubicin (DOX) from fluorescein labeled NDs (Fc-NDs). In the endosomal recycling process, the nanoparticle will pass from mildly acidic vesicle to pH ≈ 4.8; thus, it is important to investigate DOX release from NDs at different pH values. Fc-NDs released DOX dramatically under acidic conditions, while an increase in the DOX loading efficiency (up to 6.4 wt%) was observed under basic conditions. Further theoretical calculations suggest that H+ weakens the electrostatistic interaction between ND surface carboxyl groups and DOX amino groups, and the interaction energies at pH ＜ 7, pH 7 and pH ＞ 7 are 10.4 kcal mol−1, 25.0 kcal mol−1 and 27.0 kcal mol−1 respectively. Cellular imaging experiments show that Fc-NDs are readily ingested by breast adenocarcinoma (BA) cells and cell viability tests prove that they can be utilized as a safe drug delivery vehicle. Furthermore, pH triggered DOX release has been tested in vitro (pH 7.4 and pH 4.83) in breast adenocarcinoma (BA) cells. [ABSTRACT FROM AUTHOR]

The cycloaddition reactions of 4-(2-hydroxy-2-propyl)-3,4,5,6-tetrahydropyridine 1-oxide with mono- and di-substituted alkenes have been found to be highly stereo- as well as face-selective. In solution, the 6/5 fused bicyclic cycloadducts remain solely as the cis-fused invertomers in order to accommodate the bulky tertiary substituent 2-hydroxy-2-propyl in the equatorial orientation. The cycloadducts, upon peracid oxidation, leads to the exclusive formation of synthetically important second-generation cyclic aldonitrones. The stereo- and face-selectivity of the cycloaddition reactions of these second-generation nitrones bearing substituents at C(4) and C(6) have been briefly examined. One interesting finding was that treatment of the first generation nitrone i.e., 4-(2-hydroxy-2-propyl)-3,4,5,6-tetrahydropyridine 1-oxide, with mercury(II) oxide afforded a novel bicyclic nitrone, 1-oxa-5,6-dehydro-6-aza-bicyclo[3,2,1]heptane 6-oxide. [ABSTRACT FROM AUTHOR]

Abstract: A study of the stereo- and face selectivity of the cycloaddition reactions of several mono- and disubstituted alkenes with 4-hydroxymethyl-3,4,5,6-tetrahydropyridine 1-oxide has been carried out. The addition reactions have displayed a very high degree of face selectivity in the range 13-48:1. Use of dimethyl methylenemalonate as a protective group in nitrone cycloaddition reactions has been demonstrated. The invertomeric analysis revealed that the bicyclic cycloadducts remain predominantly as the cis-fused isomer, which leads to the formation of synthetically important second-generation cyclic aldonitrones via peracid oxidation. One interesting finding was that treatment of the cycloadducts with two equivalents of peracid afforded the cyclic N-hydroxy lactams, presumably via further oxidation of the aldonitrones. The piperidine ring has been elaborated by cycloaddition reaction of the second-generation nitrones with several alkenes, which in most cases gave the cycloadducts in a stereoselective manner. [Copyright &y& Elsevier]

The diastereoselectivity in the cycloaddition reactions of several mono- and disubstituted alkenes with a (-)norephedrine-derived methylenenitrone has been investigated. The stereochemical analysis of the addition products (i.e., isoxazolidines) has been carried out by X-ray, NMR, and chemical conversions. The NMR spectra of the isoxazolidines at low temperatures indicated the presence of either a single or a predominant invertomer. The stereochemistry of the invertomers and nitrogen inversion barriers are determined using complete line-shape analysis and their dependence on solvent is discussed. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Keywords: azobenzene; C8 separations; host-guest interactions; intrinsically porous materials; organic cages EN azobenzene C8 separations host-guest interactions intrinsically porous materials organic cages 21433 21433 1 11/18/20 20201123 NES 201123 B Ein stabiler und rezyklierbarer b nichtporöser Azobenzol-basierter organischer Käfig (AZO-Cage), der selektiv für I p i -Xylol (pX) gegenüber allen C SB 8 sb -Isomeren ist, wird von N. M. Khashab und Mitarbeitern in der Zuschrift auf S. 21551 vorgestellt. AZO-Cage geht einen Kristall-zu-Kristall-Phasenübergang selektiv in Gegenwart von pX in der Flüssig- und Dampfphase ein, was es zu einer idealen Plattform für die Stofftrennung von Benzolderivaten macht. AZO-Cage geht einen Kristall-zu-Kristall-Phasenübergang selektiv in Gegenwart von pX in der Flüssig- und Dampfphase ein, was es zu einer idealen Plattform für die Stofftrennung von Benzolderivaten macht. [Extracted from the article]

The cover page of the journal "Angewandte Chemie" is presented.

• Synthesis and coating of trianglamine hydrochloride on IDE substrates. • Morphological characterization of trianglamine hydrochloride crystals. • Sensing of humidity. • Analysis of the sensitivity, selectivity, hysteresis, stability, and temperature coefficient of the humidity sensor. In this work, we present a highly sensitive and selective capacitive humidity sensor. Trianglamine hydrochloride is used as the sensing material, which is synthesized by a [3+3] cyclocondensation reaction between terpthaldehyde and 1R,2R-cyclohexanediamine followed by addition of hydrochloric acid and vapor diffusion of acetone. The crystalline trianglamine hydrochloride salts are dispersed in acetonitrile and then coated on interdigitated electrode substrates by drop casting. The sensor response is characterized for relative humidity (RH) ranging from 5% to 95%. The sensor has a nonlinear response, where the sensitivity increases with an increase in RH. The sensor demonstrates, on average, normalized sensitivities of 0.015 and 6.9 per percent of RH below and above 65% RH, respectively. In addition, the sensor is characterized for hysteresis, long-term stability, effect of temperature, and selectivity. The hysteresis of the sensor is a maximum of about 20% RH and is stable for over 25 days. Temperature analysis of the sensors shows that the sensitivity decreases with increase in temperature. The material is shown to be highly selective with respect to volatile organic compounds (VOCs) and toxic/corrosive gasses. Overall, trianglamine hydrochloride is a promising material for developing a highly sensitive and selective capacitive transduction-based humidity sensor. [ABSTRACT FROM AUTHOR]

Efficient incorporation of supramolecular hosts in polymeric membranes can impart the overall matrix with new properties for a range of cutting-edge applications. Here, we introduce a Supramolecular Interfacial Assembly (SIA) method for the fabrication of polymeric membranes featuring embedded macrocycles. Through harnessing the quasi-liquid nature of the concentrated polymer solution, SIA orchestrates the homogenous spreading of macrocycles in an aqueous layer on its surface, leading to the creation of an interface between "water/water" phases, subsequently forming a cross-linked membrane driven by supramolecular electrostatic interactions. Remarkably, compared to the traditional interfacial polymerization, SIA adheres to a "green" paradigm without the need for organic solvents. The resultant composite membrane exhibits superior performance in organic solvent nanofiltration (OSN), owing to the precise molecular sieving property provided by the macrocycles with well-defined permanent cavities. This fabrication method holds great promise for the innovative design of composite membranes, which can greatly impact the production of smart membrane materials for advanced technology applications in the future., (© 2024 Wiley‐VCH GmbH.)

Realizing quantitative surface-enhanced Raman scattering (SERS) analysis is extremely helpful and challenging. Here, we utilize a facile method to synthesize spiked plasmonic nanorods with an interior gap. The Raman signal from the molecules embedded in the gap can be dramatically enhanced, leading to strong, stable, and reproducible SERS signals that can be used as an internal reference for quantitative SERS analysis. We demonstrate that the rough exterior surface has a good performance in enhancing the Raman signal of polycyclic aromatic hydrocarbon molecules adsorbed on the surface. The result shows that this method is applicable for a large range of analyte concentrations and there is an excellent linear relationship between the SERS intensity ratio and the analyte concentration (0.5-100 μM)., Competing Interests: The authors declare no competing financial interest.

Porous materials with molecular-scale ordering have attracted major attention mainly because of the possibility to engineer their pores for selective applications. Periodic mesoporous organosilica is a class of hybrid materials where self-assembly of the organic linkers provides a crystal-like pore wall. However, unlike metal coordination, specific geometries cannot be predicted because of the competitive and dynamic nature of noncovalent interactions. Herein, we study the influence of competing noncovalent interactions in the pore walls on the biodegradation of organosilica frameworks for drug delivery application. These results support the importance of studying self-assembly patterns in hybrid frameworks to better engineer the next generation of dynamic or "soft" porous materials., Competing Interests: The authors declare no competing financial interest.