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Molecules in confined spaces exhibit unusual behaviors that are not typically observed in bulk systems. Such behavior can provide alternative strategies for exploring new reaction pathways. Cleavage of the C=N bond of Nile red (NR) in solution is an irreversible reaction. Here, we used spatial confinement within a cationic micelle‐confined system to convert this reaction to a reversible process. The fluorescence of NR shifted between red and green for nine cycles. The new chemical pathway based on spatial confinement can be attributed to two factors: increasing the local concentration of reactants and reducing the reaction energy barrier. This effect is supported by both experimental evidence and theoretical calculations. The cross‐linked silica shell comprising the confinement chamber stabilizes the enclosed molecules. This reduces fluorophore leakage and maintains fluorescence intensity in most environments, including in solution, on paper, and in hydrogel films, and expands practical applications in encrypted information and multi‐informational displays. [ABSTRACT FROM AUTHOR]

The direct C−H functionalization of 1,2‐benzazaborines, especially asymmetric version, remains a great challenge. Here we report a palladium‐catalyzed enantioselective C−H olefination and allylation reactions of 1,2‐benzazaborines. This asymmetric approach is a kinetic resolution (KR), providing various C−B axially chiral 2‐aryl‐1,2‐benzazaborines and 3‐substituted 2‐aryl‐1,2‐benzazaborines in generally high yields with excellent enantioselectivities (selectivity (S) factor up to 354). The synthetic potential of this reaction is showcased by late‐stage modification of complex molecules, scale‐up reaction, and applications. [ABSTRACT FROM AUTHOR]

Many microRNAs (miRNAs) are characteristically found in cancer cells, making miRNAs promising marker biomolecules for cancer diagnosis and therapeutics. However, it is challenging to use miRNA as a cancer signature because it is difficult to convert the nucleic acid sequence information into molecular functionality. To address this challenge, we realize nucleic acid‐to‐small molecule converters using hairpin DNA circuits. Harnessing a Staudinger reduction as a trigger for the conversion, we constructed hybridization chain reaction (HCR) and catalytic hairpin assembly (CHA) circuits that respond to oncogenic miR‐21. Fluorophore and dye molecules were released in response to miR‐21 through the HCR, providing fluorogenic and chromogenic readouts. Selective cytotoxicity in miR‐21‐abundant cells was realized by the CHA to release the anticancer drug SN‐38. This would be the first example of selective activation of a small‐molecule prodrug triggered by oncogenic miRNA in human living cells. [ABSTRACT FROM AUTHOR]

Delving into the influence of strain on organic reactions in small molecules at the molecular level can unveil valuable insight into developing innovative synthetic strategies and structuring molecules with superior properties. Herein, we present a molecular‐strain engineering approach to facilitate the consecutive [1,2]‐aryl shift (formal [1,3]‐aryl shift) in molecular bows (MBs) that integrate 1,4‐dimethoxy‐2,5‐cyclohexadiene moieties. By introducing ring strain into MBs through tethering the bow limb, we can harness the intrinsic mechanical forces to drive multistep aryl shifts from the para‐ to the meta‐ to the ortho‐position. Through the use of precise intramolecular strain, the seemingly impractical [1,3]‐aryl shift was realized, resulting in the formation of ortho‐disubstituted products. The solvent and temperature play a crucial role in the occurrence of the [1,3]‐aryl shift. The free energy calculations with inclusion of solvation support a feasible mechanism, which entails multistep carbocation rearrangements, for the formal [1,3]‐aryl shift. By exploring the application of molecular strain in synthetic chemistry, this research offers a promising direction for developing new tools and strategies towards precision organic synthesis. [ABSTRACT FROM AUTHOR]

For the fabrication of next‐generation MOF‐based devices the availability of highly adaptable materials in suitable shapes is crucial. Here, we present thin films of a metal–organic framework (MOF) containing photoreactive benzophenone units. Crystalline, oriented and porous films of the zirconium‐based bzpdc‐MOF (bzpdc=benzophenone‐4‐4′‐dicarboxylate) are prepared by direct growth on silicon or glass substrates. Via a subsequent photochemical modification of the Zr‐bzpdc‐MOF films, various properties can be tuned postsynthetically by covalent attachment of modifying agents. Apart from the modification with small molecules, also grafting‐from polymerization reactions are possible. In a further extension, 2D structuring and photo‐writing of defined structures is also possible, for example by using a photolithographic approach, paving the way towards micro‐patterned MOF surfaces. [ABSTRACT FROM AUTHOR]

We describe the use of the cyaphide‐azide 1,3‐dipolar cycloaddition reaction for the synthesis of a new class of inorganic rotaxanes containing gold(I) triazaphosphole stoppers. Electron‐deficient bis‐azides, which thread perethylated pillar[5]arene in aromatic solvents, readily react with two equivalents of Au(IDipp)(CP) (IDipp=1,3‐bis‐(2,6‐diisopropylphenyl)‐imidazol‐2‐ylidene) to afford interlocked molecules via an inorganic click reaction. These transformations proceed in good yields (ca. 65 %) and in the absence of a catalyst. The resulting organometallic rotaxanes are air‐ and moisture‐stable and can be purified by column chromatography under aerobic conditions. The targeted rotaxanes were characterized by multi‐element nuclear magnetic resonance (NMR) spectroscopy, mass‐spectrometry, and single‐crystal X‐ray diffraction. [ABSTRACT FROM AUTHOR]

Relaying conformational change over several nanometers is central to the function of allosterically regulated proteins. Replicating this mechanism artificially would provide important communication tools, but requires nanometer‐sized molecules that reversibly switch between defined shapes in response to signaling molecules. In this work, 1.8 nm long rigid rod oligo(phenylene‐ethynylene)s are scaffolds for switchable multi‐squaramide hydrogen‐bond relays. Each relay can adopt either a parallel or an antiparallel orientation relative to the scaffold; the preferred orientation is dictated by a director group at one end. An amine director responded to proton signals, with acid‐base cycles producing multiple reversible changes in relay orientation that were reported by a terminal NH, which is 1.8 nm distant. Moreover, a chemical fuel acted as a dissipative signal. As the fuel was consumed, the relay reverted to its original orientation, illustrating how information from out‐of‐equilibrium molecular signals can be communicated to a distant site. [ABSTRACT FROM AUTHOR]

A ferrocene‐based capsule is spontaneously and quantitatively formed in water by the assembly of bent amphiphiles carrying two ferrocene units. The disassembly and assembly of the new organometallic capsule, with a well‐defined and highly condensed ferrocene core, are demonstrated by chemical redox stimuli in a fully reversible fashion under ambient conditions. In contrast to previously reported multiferrocene assemblies, only the present capsule efficiently encapsulates typical organic/inorganic dyes as well as electron‐accepting molecules in water. As a result, unusual host‐guest charge‐transfer (CT) interactions, displaying relatively wide absorption bands in the visible to near‐infrared region (λ=650–1350 nm), are observed upon the encapsulation of acceptors (i.e. chloranil and TCNQ). The resultant encapsulation‐induced CT interactions can be released by a redox stimulus through the disassembly of the capsule. [ABSTRACT FROM AUTHOR]

Enantioselective synthesis of N−N biaryl atropisomers is an emerging area but remains underexplored. The development of efficient synthesis of N−N biaryl atropisomers is in great demand. Herein, the construction of N−N biaryl atropisomers through iridium‐catalyzed asymmetric C−H alkylation is reported for the first time. In the presence of readily available Ir precursor and Xyl‐BINAP, a variety of axially chiral molecules based on indole‐pyrrole skeleton were obtained in good yields (up to 98 %) with excellent enantioselectivity (up to 99 % ee). In addition, N−N bispyrrole atropisomers could also be synthesized in excellent yields and enantioselectivity. This method features perfect atom economy, wide substrate scope, and multifunctionalized products allowing diverse transformations. [ABSTRACT FROM AUTHOR]

A unique benzannulation strategy for regioselective de novo synthesis of densely functionalized phenols is described. Through metal‐mediated formal [2+2+1+1] cycloaddition of two different alkynes and two molecules of CO, a series of densely functionalized phenols were obtained. The benzannulation strategy allows efficient regioselective installation up to five different substituents on a phenol ring. The resulting phenols have a substitution pattern different from those obtained from Dötz and Danheiser benzannulations. [ABSTRACT FROM AUTHOR]

G protein‐coupled receptors initiate signal transduction in response to ligand binding. Growth hormone secretagogue receptor (GHSR), the focus of this study, binds the 28 residue peptide ghrelin. While structures of GHSR in different states of activation are available, dynamics within each state have not been investigated in depth. We analyze long molecular dynamics simulation trajectories using "detectors" to compare dynamics of the apo and ghrelin‐bound states yielding timescale‐specific amplitudes of motion. We identify differences in dynamics between apo and ghrelin‐bound GHSR in the extracellular loop 2 and transmembrane helices 5–7. NMR of the GHSR histidine residues reveals chemical shift differences in these regions. We evaluate timescale specific correlation of motions between residues of ghrelin and GHSR, where binding yields a high degree of correlation for the first 8 ghrelin residues, but less correlation for the helical end. Finally, we investigate the traverse of GHSR over a rugged energy landscape via principal component analysis. [ABSTRACT FROM AUTHOR]

Synthetic methodology is considered a holy grail in both organic chemistry and materials science. Over the past few decades, researchers have explored graphene‐type molecules (or nanographenes) through classic Scholl oxidative cyclodehydrogenation. Despite the successes achieved with various nanographenes, the development of new methods to synthesize these highly desired molecules lags behind. Herein, we developed a facile and effective method to produce a series of nanographenes bearing nitrogen (N)‐doped pentagon‐heptagon pairs in acceptable yields. Modification of the heptagonal ring endowed the resultant nanographenes with tunable physicochemical properties; for instance, M9 exhibited both aggregation‐caused quenching and aggregation‐induced emission behavior. Most strikingly, novel nanographenes containing N‐doped pentagon‐octagon pairs were also obtained using the same synthetic strategy, demonstrating the superior versatility and efficiency of the proposed ring expansion method. [ABSTRACT FROM AUTHOR]

The solid‐state structure of decamethylsilicocene Cp*2Si with a bent and a linear molecule in the same unit cell was so far considered an exception in relation to the structures of its all‐bent heavier analogues Cp*2E with E=Ge, Sn, Pb. Here, we present the solution to this conundrum by reporting a low‐temperature phase, where all three symmetrically independent molecules are present in a bent formation. This reversible enantiotropic phase transition occurs in the temperature range between 80 K and 130 K and provides a rationale for the unexpected linear molecule based in entropy beyond hand‐waving explanations such as electronic reasons or packing effects. [ABSTRACT FROM AUTHOR]

Mechanically interlocked molecules (MIMs) have gained increasing interest during the last decades, not only because of their aesthetic appeal, but also because their unique properties have allowed them to find applications in nanotechnology, catalysis, chemosensing and biomedicine. Herein we describe how a pyrene molecule with four octynyl substituents can be easily encapsulated within the cavity of a tetragold(I) rectangle‐like metallobox, by template formation of the metallo‐assembly in the presence of the guest. The resulting assembly behaves as a mechanically interlocked molecule (MIM), in which the four long limbs of the guest protrude from the entrances of the metallobox, thus locking the guest inside the cavity of the metallobox. The new assembly resembles a metallo‐suit[4]ane, given the number of protruding long limbs and the presence of the metal atoms in the host molecule. However, unlike normal MIMs, this molecule can release the tetra‐substituted pyrene guest by the addition of coronene, which can smoothly replace the guest in the cavity of the metallobox. Combined experimental and computational studies allowed the role of the coronene molecule in facilitating the release of the tetrasubstituted pyrene guest to be explained, through a process that we named "shoehorning", as the coronene compresses the flexible limbs of the guest so that it can reduce its size to slide in and out the metallobox. [ABSTRACT FROM AUTHOR]

Synthetic methods for unsymmetrical disulfides are greatly needed owing to their applications in drug discovery, linker chemistry, and materials sciences. In this study, a new shelf‐stable and easy‐to‐prepare bilateral disulfurating platform molecule, N‐(morpholine‐4‐dithio)phthalimide, has been developed for the divergent synthesis of unsymmetrical disulfides. The amino and imide leaving groups of this reagent can be orthogonally transformed. Under acidic conditions, the amino moiety undergoes selective protonation and thus can be displaced by various carbon nucleophiles, such as allyl trimethylsilanes, alkynyl silanes, and electron‐rich arenes, leaving the phthalimide moiety untouched. Meanwhile, the phthalimide leaving group is amenable to substitution under basic or neutral conditions. The combination of these transformations provides rapid access to diverse unsymmetrical disulfides through two C−S bond‐forming reactions. [ABSTRACT FROM AUTHOR]

Li−O2 batteries with bis(trifluoromethanesulfonyl)imide‐based ionic liquid (TFSI‐IL) electrolyte are promising because TFSI‐IL can stabilize O2− to lower charge overpotential. However, slow Li+ transport in TFSI‐IL electrolyte causes inferior Li deposition. Here we optimize weak solvating molecule (anisole) to generate anisole‐doped ionic aggregate in TFSI‐IL electrolyte. Such unique solvation environment can realize not only high Li+ transport parameters but also anion‐derived solid electrolyte interface (SEI). Thus, fast Li+ transport is achieved in electrolyte bulk and SEI simultaneously, leading to robust Li deposition with high rate capability (3 mA cm−2) and long cycle life (2000 h at 0.2 mA cm−2). Moreover, Li−O2 batteries show good cycling stability (a small overpotential increase of 0.16 V after 120 cycles) and high rate capability (1 A g−1). This work provides an effective electrolyte design principle to realize stable Li deposition and high‐performance Li−O2 batteries. [ABSTRACT FROM AUTHOR]

Prenylation is a ubiquitous late‐stage modification in nature that often confers significantly improved bioactivity for secondary metabolites. While this lipophilic modification renders enhanced potency, the lipophilic tag(s) can diminish bioavailability and adversely alter drug transportation and metabolism. Thus, a functional‐group‐tolerant, mild, and selective late‐stage C−H functionalization of prenyl tags would present a great potential in drug discovery programs but could also impact other fields, such as agrochemistry and chemical biology. Herein we report an exocyclic‐strain‐driven cross‐metathesis reaction of prenyl tags, a formal double C−H oxidation protocol, that can be used for the selective late‐stage derivatization of prenylated compounds and natural products. This methodology avoids the need for prefunctionalization of target molecules and affords ready access to an unprecedented library of oxo‐ and aza‐prenylated complex molecules. Thus, in a broader context, this methodology extends late‐stage functionalization beyond that available to nature. [ABSTRACT FROM AUTHOR]

Transition metal‐catalyzed enantioselective C−H activation of prochiral sulfoximines for non‐annulated products remains a formidable challenge. We herein report iridium‐catalyzed enantioselective C−H borylation of N‐silyl diaryl sulfoximines using a well‐designed chiral bidentate boryl ligand with a bulky side arm. This method is capable of accommodating a broad range of substrates under mild reaction conditions, affording a vast array of chiral sulfoximines with high enantioselectivities. We also demonstrated the synthetic utility on a preparative‐scale C−H borylation for diverse downstream transformations, including the synthesis of chiral version of bioactive molecules. Computational studies showed that the bulky side arm of the ligand confers high regio‐ and enantioselectivity through steric effect. [ABSTRACT FROM AUTHOR]

Carbene‐stabilized diborynes of the form LBBL (L=N‐heterocyclic carbene (NHC) or cyclic alkyl(amino)carbene (CAAC)) induce rapid, high yielding, intermolecular ortho‐C−H borylation at N‐heterocycles at room temperature. A simple pyridyldiborene is formed when an NHC‐stabilized diboryne is combined with pyridine, while a CAAC‐stabilized diboryne leads to activation of two pyridine molecules to give a tricyclic alkylideneborane, which can be forced to undergo a further H‐shift resulting in a zwitterionic, doubly benzo‐fused 1,3,2,5‐diazadiborinine by heating. Use of the extended N‐heteroaromatic quinoline leads to a borylmethyleneborane under mild conditions via an unprecedented boron‐carbon exchange process. [ABSTRACT FROM AUTHOR]

We report a new synthetic strategy for the flexible preparation of forskolin‐like molecules. The approach is different from the previously published works and employs a convergent assembly of the tricyclic labdane‐type core from pre‐functionalized cyclic building blocks. Stereoselective Michael addition enabled the fragment coupling with excellent control over three newly created contiguous stereocenters, all‐carbon quaternary centers included. Silyl enol ether‐promoted ring‐opening metathesis paired with ring closure were the other key steps enabling concise assembly of the tricyclic core. Late‐stage functionalization sequences transformed the tricyclic intermediates into a set of different forskolin‐like molecules. The modular nature of the synthetic scheme described herein has the potential to become a general platform for the preparation of analogs of forskolin and other complex tricyclic labdanes. [ABSTRACT FROM AUTHOR]

Under cold pressure sp1/sp2‐to‐sp3 hybridization transformation has been exclusively observed in covalent or molecular crystals overwhelmingly above ≈10 GPa, and the approaches to lower the transition pressure are limited on external heat‐treatment and/or catalyzers. Herein we demonstrate that, by internal‐lattice stress‐transfer from ionic to covalent groups, the transformation can be significantly prompted, as shown in a crystal of LiBO2 under 2.85 GPa for the first case in ionic crystals. This unprecedentedly low transformation pressure is ascribed to the enhanced localized stress on covalent B−O frames transferred from ionic Li−O bonds in LiBO2, and accordingly the corresponding structural feature is summarized. This work provides an internal structural regulation strategy for pressure‐reduction of the s‐p orbital hybridization transformation and extends the sp1/sp2‐to‐sp3 transformation landscape from molecular and covalent compounds to ionic systems. [ABSTRACT FROM AUTHOR]

Reported herein is the efficient synthesis of tetra‐ and tri‐substituted (Z)‐fluoro‐ and (Z)‐chloro‐borylalkenes by the Boron–Wittig reaction of ketones and aldehydes with bench‐top stable halo‐diborylmethanes. The substrate scope is broad and the Boron–Wittig reaction proceeds from a diverse range of ketones and aldehydes including biologically relevant molecules with fluoro‐ or chloro‐diborylmethanes, providing tetra‐ and tri‐substituted (Z)‐fluoro‐ and (Z)‐chloro‐borylalkenes in good yields with high stereoselectivity. The utilities of the obtained (Z)‐fluoro‐ and (Z)‐chloro‐borylalkenes are highlighted by further modifications to afford fluoroalkene derivatives or all‐carbon substituted alkene. [ABSTRACT FROM AUTHOR]

Mechanically interlocked molecules based on oligoparaphenylene‐derived nanohoops, particularly those without heteroatoms, are synthetically challenging and topologically intriguing targets. Herein, a π‐conjugated covalent template strategy based on azo group has been developed, which features dual intramolecular macrocyclizations directed by a tetra‐substituted azobenzene core, followed by traceless removal of the azo linker. Employing this strategy, the efficient synthesis of a novel all‐benzene [2]catenane consisting of meta‐cycloparaphenylenes has been accomplished. [ABSTRACT FROM AUTHOR]

The development of new approaches to installing diverse carbon fragments to a nitrogen atom has attracted considerable attention in chemical science. While numerous strategies have been devised to forge C(sp3)−N bonds, one conceptually powerful and straightforward approach is to insert a transformable sp3‐carbon unit onto a nitrogen atom for modular diversification. Here we describe the successful synthesis of halo‐diborylmethanes and their applications to the preparation of nitrogen‐substituted diborylmethanes through their homologative coupling with a variety of nitrogen nucleophiles including biologically relevant molecules. This process exhibits a remarkably broad substrate scope, and the usefulness of the obtained compounds is demonstrated by the modular diversification of the diborylmethyl group to access various nitrogen‐containing molecules. [ABSTRACT FROM AUTHOR]

Most of the bowl‐shaped molecules are synthesized via a core‐periphery strategy with the bowl rim closed at the final stage. However, the construction of heteroatom‐doped buckybowls by the periphery‐core method with the bowl bottom sealed by inserting new atoms in the last step is quite limited. Herein we report the synthesis of a bowl‐shaped compound containing four sulfur atoms and two embedded N−B bonds with the ratio of carbon atom and heteroatom as low as four through a periphery‐core strategy. Crystallographic analysis confirms the formation of a bowl‐shaped structure. The multiple heteroatoms alter the molecular electronic structure, thus resulting in the distinct aromaticity when compared with its all‐carbon congener. The electron‐rich buckybowl shows a strong interaction with the electron‐deficient fullerene C60 by forming a 1 : 1 complex in toluene. [ABSTRACT FROM AUTHOR]

The two major barriers of practical lithium–sulfur batteries are the poor reversibility of lithium‐metal anode and sluggish kinetics of sulfur cathode. Here, we report a simple yet cogent, molecular tailoring approach for lithium polysulfides, enabling a synergistic enhancement of anode reversibility and cathode kinetics. We show that SnI4 coordinates with lithium polysulfides to form soluble complexes, resulting in a Li2SnS3‐rich anode interphase layer. As Li2SnS3 is stable against parasitic reactions and has a lower ionic resistance over cycling, the Li plating/stripping efficiency is greatly improved. In addition, the formation of soluble complexes between SnI4 and lithium polysulfides play a non‐negligible role in suppressing the clustering behavior of lithium polysulfide molecules, resulting in a significant enhancement in sulfur conversion kinetics under lean electrolyte conditions. The synergistic improvement is validated in anode‐free, lean‐electrolyte pouch cells with a Li2S cathode that displays capacity retention of 78 % after 100 cycles. [ABSTRACT FROM AUTHOR]

Synthetic messenger RNA (mRNA) switches are powerful synthetic biological tools that can sense cellular molecules to manipulate cell fate. However, their performances are limited by high output signal noise due to leaky output protein expression. Here, we designed a readout control module that disables protein leakage from generating signal. Aptamer array on the switch guides the inactive output protein to self‐assemble into functional assemblies that generate output signal. Leaky protein expression fails to saturate the array, thus produces marginal signal. In this study, we demonstrated that switches with this module exhibit substantially lower signal noise and, consequently, higher input sensitivity and wider output range. Such switches are applicable for different types of input molecules and output proteins. The work here demonstrates a new type of spatially guided protein self‐assembly, affording novel synthetic mRNA switches that promise accurate cell manipulation for biomedical applications. [ABSTRACT FROM AUTHOR]

Ammonia oxidation catalyzed by molecular compounds is of current interest as a carbon‐free source of dihydrogen. Activation of N−H bonds through coordination to transition metal centers is a key reaction in this process. We report the substantial activation of ammonia via reaction with low‐valent molybdenum complexes of a diborate pentadentate ligand system. Spontaneous loss of dihydrogen from (B2Pz4Py)MoII−NH3 at room temperature to produce the dinuclear μ‐nitrido compound (B2Pz4Py)Mo‐N‐Mo(B2Pz4Py) is observed due to substantial N−H bond weakening upon coordination to Mo. Mechanistic details are supported through the experimental observation/characterization of terminal amido, imido and nitrido complexes and density functional theory computations. The generally under‐appreciated role of bridging nitrido intermediates is revealed and discussed, providing guidance for further catalyst development for this process. [ABSTRACT FROM AUTHOR]

We herein demonstrated an efficient method for the atroposelective construction of nine‐membered carbonate‐bridged biaryls through vinylidene ortho‐quinone methide (VQM) intermediates. Diverse products with desirable pharmacological features were synthesized in satisfying yields and good to excellent enantioselectivities. In subsequent bioassays, several agents showed considerable antiproliferative activity via the mitochondrial‐related apoptosis mechanism. Further transformations produced more structural diversity and may inspire new ideas for developing functional molecules. [ABSTRACT FROM AUTHOR]

We report a state‐of‐the‐art spectroscopic study of an archetypical barbaralone, conclusively revealing the valence tautomerism phenomena for this bistable molecular system. The two distinct 1‐ and 5‐substituted valence tautomers have been isolated in a supersonic expansion for the first time and successfully characterized by high‐resolution rotational spectroscopy. This work provides irrefutable experimental evidence of the [3,3]‐rearrangement in barbaralones and highlights the use of rotational spectroscopy to analyze shape‐shifting mixtures. Moreover, this observation opens the window toward the characterization of new fluxional systems in the isolation conditions of the gas phase and should serve as a reference point in the general understanding of valence tautomerism. [ABSTRACT FROM AUTHOR]

Although doping can induce room‐temperature phosphorescence (RTP) in heavy‐atom free organic systems, it is often challenging to match the host and guest components to achieve efficient intersystem crossing for activating RTP. In this work, we developed a simple descriptor ΔE to predict host molecules for matching the guest RTP emitters, based on the intersystem crossing via higher excited states (ISCHES) mechanism. This descriptor successfully predicted five commercially available host components to pair with naphthalimide (NA) and naphtho[2,3‐c]furan‐1,3‐dione (2,3‐NA) emitters with a high accuracy of 83 %. The yielded pairs exhibited bright yellow and green RTP with the quantum efficiency up to 0.4 and lifetime up to 1.67 s, respectively. Using these RTP pairs, we successfully achieved multi‐layer message encryption. The ΔE descriptor could provide an efficient way for developing doping‐induced RTP materials. [ABSTRACT FROM AUTHOR]

Pyracylene is a unique cyclopenta‐fused polycyclic aromatic hydrocarbon (CP‐PAH) that exhibits dual aromatic characteristics. Herein we report the synthesis of doubly N‐doped benzannulated pyracylenes, namely dibenzodiazapyracylenes, by oxidative N−N linking reaction of [2.2](2,5)pyrrolophane‐type precursors. Dibenzodiazapyracylenes displayed well‐ordered π‐stacked molecular packing in the solid state, which were feasible for effective hole‐transporting along the stacking direction. High carrier mobility was estimated by microwave conductivity measurements as compared to dibenzoullazine. The high HOMO level of dibenzodiazapyracylene was verified by electrochemistry and its persistent radical cation species has been detected. [ABSTRACT FROM AUTHOR]

LiCH3 and LiCH2CH3 react with the complex [Mo2(H)2(μ‐AdDipp2)2(thf)2] (1⋅thf) with coordination of two molecules of LiCH2R (R=H, CH3) and formation of complexes [Mo2{μ‐HLi(thf)CH2R}2(AdDipp2)2], 5⋅LiCH3 and 5⋅LiCH2CH3, respectively (AdDipp2=HC(NDipp)2; Dipp=2,6‐iPr2C6H3; thf=C4H8O). Due to steric hindrance, only one molecule of LiC6H5 adds to 1⋅thf generating the complex [Mo2(H){μ‐HLi(thf)C6H5}(μ‐AdDipp2)2], (4⋅LiC6H5). Computational studies disclose the existence of five‐center six‐electron bonding within the H−Mo≣Mo−C−Li metallacycles, with a mostly covalent H−Mo≣Mo−C group and predominantly ionic Li−C and Li−H interactions. However, the latter bonds exhibit non‐negligible covalency, as indicated by X‐ray, computational data and the large one‐bond 6,7Li,1H and 6,7Li,13C NMR coupling constants found for the three‐atom H−Li−C chains. By contrast, the phenyl group in 4⋅LiC6H5 coordinates in an η2 fashion to the lithium atom through the ipso and one of the ortho carbon atoms. [ABSTRACT FROM AUTHOR]

We report a simple and effective approach to organic molecules exhibiting bright circularly polarized luminescence (CPL) by combining a chiral cyclic molecular scaffold and multiple excimer‐enabling moieties. An α‐cyclodextrin (CyD) scaffold was modified with six pyrenyl groups to obtain pyrene–cyclodextrins (PCDs) in a one‐step synthesis from commercially available compounds. The PCDs exhibited high molar extinction coefficients (ϵ≈105 M−1 cm−1), polarized emission with a good dissymmetry factor (|glum|≈10−2), and quantum yield (Φf≈0.5). Owing to the excellent photophysical properties of the PCDs, the circularly polarized luminescence brightness (BCPL) reached 340 M−1 cm−1. Photophysical and chiroptical studies of the PCDs with only five pyrene units and with linkers of various lengths connecting the CyD with the pyrene units revealed that the formation of a pyrene excimer in a spatially crowded environment is crucial for CPL anisotropy. This study paves the way for the development of bright CPL organic molecules. [ABSTRACT FROM AUTHOR]

Purification of C2H4 from an C2H4 /C2H6 mixture is one of the most challenging separation processes, which is achieved mainly through energy‐intensive, cryogenic distillation in industry. Sustainable, non‐distillation methods are highly desired as alternatives. We discovered that the fluorinated bis(pyrazolyl)borate ligand supported copper(I) complex {[(CF3)2Bp]Cu}3 has features very desirable in an olefin–paraffin separation material. It binds ethylene exclusively over ethane generating [(CF3)2Bp]Cu(C2H4). This molecular compound exhibits extremely high and record ideal adsorbed solution theory (IAST) C2H4 /C2H6 gas separation selectivity, affording high purity (>99.5 %) ethylene that can be readily desorbed from separation columns. In‐situ PXRD provides a "live" picture of the reversible conversion between [(CF3)2Bp]Cu(C2H4) and the ethylene‐free sorbent in the solid‐state, driven by the presence or removal of C2H4. Molecular structures of trinuclear {[(CF3)2Bp]Cu}3 and mononuclear [(CF3)2Bp]Cu(C2H4) are also presented. [ABSTRACT FROM AUTHOR]

Disclosed herein is the first carbene‐organocatalyzed asymmetric addition of phosphine nucleophiles to the in situ generated α,β‐unsaturated acyl azolium intermediates. Our reaction enantioselectively constructs carbon–phosphine bonds and prepares chiral phosphines with high optical purities. The phosphine products are suitable for transforming to chiral ligands or catalysts with applications in asymmetric catalysis. The diarylalkyl or trialkyl phosphine products from our catalytic reactions, air‐sensitive and reactive in nature, can be trapped (and stored) in their sulfur‐oxidized form for operational simplicities. [ABSTRACT FROM AUTHOR]

In the realm of solids, metal–organic frameworks (MOFs) offer unique possibilities for the rational engineering of tailored physical properties. These derive from the modular, molecular make‐up of MOFs, which allows for the selection and modification of the organic and inorganic building units that construct them. The adaptable properties make MOFs interesting materials for photocatalysis, an area of increasing significance. But the molecular and porous nature of MOFs leaves the field, in some areas, juxtapositioned between semiconductor physics and homogeneous photocatalysis. While descriptors from both fields are applied in tandem, the gap between theory and experiment has widened in some areas, and arguably needs fixing. Here we review where MOFs have been shown to be similar to conventional semiconductors in photocatalysis, and where they have been shown to be more like infinite molecules in solution. We do this from the perspective of band theory, which in the context of photocatalysis, covers both the molecular and nonmolecular principles of relevance. [ABSTRACT FROM AUTHOR]

The cyano(triphenylsilyl)phosphanide anion was prepared as a sodium salt from 2‐phosphaethynolate. The electronic structure of this new cyano(silyl)phosphanide was studied via computational methods and its reactivity investigated using various electrophiles and Lewis acids, demonstrating its P‐ and N‐nucleophilicity. The ambident reactivity is in agreement with computations. The silyl group also shows lability and therefore the cyano(silyl)phosphanide can be considered as a phosphacyanamide synthon, [PCN]2−, and serves as building block for the transfer of a PCN moiety. [ABSTRACT FROM AUTHOR]

The synthesis, structures, and properties of [4]cyclonaphthodithiophene diimides ([4]C‐NDTIs) are described. NDTIs as important n‐type building blocks were catenated in the α‐positions of thiophene rings via an unusual electrochemical‐oxidation‐promoted macrocyclization route. The thiophene–thiophene junction in [4]C‐NDTIs results in an ideal pillar shape. This interesting topology, along with appealing electronic and optical properties inherited from the NDTI units, endows the [4]C‐NDTIs with both near‐infrared (NIR) light absorptions, strong excitonic coupling, and tight encapsulation of C60. Stable orientations of the NDTI units in the nanopillars lead to stable inherent chirality, which enables detailed circular dichroism studies on the impact of isomeric structures on π‐conjugation. Remarkably, the [4]C‐NDTIs maintain the strong π–π stacking abilities of NDTI units and thus adopt two‐dimensional (2D) lattice arrays at the molecular level. These nanopillar molecules have great potential to mimic natural photosynthetic systems for the development of multifunctional organic materials. [ABSTRACT FROM AUTHOR]

A geometrically constrained phosphine bearing a tridentate NNS pincer ligand is reported. The effect of the geometric constraint on the electronic structure was probed by theoretical calculations and derivatization reactions. Reactions with N−H bonds result in formation of cooperative addition products. The thermochemistry of these transformations is strongly dependent on the substrate, with ammonia activation being thermoneutral. This represents the first example of a molecular compound that reversibly activates ammonia via N−H bond scission in solution upon mild heating. [ABSTRACT FROM AUTHOR]

N−C Biaryl atropisomers are prevalent in natural products and bioactive drug molecules. However, the enantioselective synthesis of such molecules has not developed significantly. Particularly, the enantioselective synthesis of N−C biaryl atropisomers by stereoselective metal‐catalyzed aryl amination remains unprecedented. Herein, a Pd‐catalyzed cross‐coupling strategy is presented for the synthesis of N−C axially chiral biaryl molecules. A broad spectrum of N−C axially chiral compounds was obtained with excellent enantioselectivities (up to 99 % ee) and good yields (up to 98 %). The practicality of this reaction was validated in the synthesis of useful biological molecules. [ABSTRACT FROM AUTHOR]

Although numerous adsorbent materials have been reported for the capture of radioactive iodine, there is still demand for new absorbents that are economically viable and can be prepared by reliable synthetic protocols. Herein, we report a coordination‐driven self‐assembly strategy towards adsorbents for the sequential confinement of iodine molecules. These adsorbents are versatile heterometallic frameworks constructed from aluminum molecular rings of varying size, flexible copper ions, and conjugated carboxylate ligands. Additionally, these materials can quickly remove iodine from cyclohexane solutions with a high removal rate (98.8 %) and considerable loading capacity (555.06 mg g−1). These heterometallic frameworks provided distinct pore sizes and binding sites for iodine molecules, and the sequential confinement of iodine molecules was supported by crystallographic data. This work not only sets up a bridge between molecular rings and infinite porous networks but also reveals molecular details for the underlying host–guest binding interactions at crystallographic resolution. [ABSTRACT FROM AUTHOR]

We orderly assembled zero‐dimensional 2‐methylimidazole (mim) molecules into unprecedented supramolecule array membranes (SAMs) through solvent‐free vapor processing, realizing the intermolecular spacing of mim at ca. 0.30 nm available as size‐sieving channels for distinguishing the tiny difference between H2 (kinetic diameter: 0.289 nm) and CO2 (kinetic diameter: 0.33 nm). The highly oriented and dense membranes yield a separation factor above 3600 for equimolar H2/CO2 mixtures, which is one order of magnitude higher than those of the state‐of‐the‐art membranes defining 2017's upper bound for H2/CO2 separation. These SAMs define a new benchmark for molecular sieve membranes and are of paramount importance to precombustion carbon capture. Given the range of supramolecules, we anticipate SAMs with variable intermolecular channels could be applied in diversified separations that are prevalent in chemical processes. [ABSTRACT FROM AUTHOR]

A dynamic nucleophilic aromatic substitution of tetrazines (SNTz) is presented herein. It combines all the advantages of dynamic covalent chemistry with the versatility of the tetrazine moiety. Indeed, libraries of compounds or sophisticated molecular structures can be easily obtained, which are susceptible to post‐functionalization by inverse electron demand Diels–Alder (IEDDA) reaction, which also locks the exchange. Additionally, the structures obtained can be disassembled upon the application of the right stimulus, either UV irradiation or a suitable chemical reagent. Moreover, SNTz is compatible with the imine chemistry of anilines. The high potential of this methodology has been proved by building two responsive supramolecular systems: A macrocycle that displays a light‐induced release of acetylcholine; and a truncated [4+6] tetrahedral shape‐persistent fluorescent cage, which is disassembled by thiols unless it is post‐stabilized by IEDDA. [ABSTRACT FROM AUTHOR]

On‐surface synthesis (OSS) involving relatively high energy barriers remains challenging due to a typical dilemma: firm molecular anchor is required to prevent molecular desorption upon the reaction, whereas sufficient lateral mobility is crucial for subsequent coupling and assembly. By locking the molecular precursors on the substrate then unlocking them during the reaction, we present a strategy to address this challenge. High‐yield synthesis based on well‐defined decarboxylation, intermediate transition, and hexamerization is demonstrated, resulting in an extended and ordered network exclusively composed of the newly synthesized macrocyclic compound. Thanks to the steric hindrance of its maleimide group, we attain a preferential selection of the coupling. This work unlocks a promising path to enrich the reaction types and improve the coupling selectivity hence the structual homogeneity of the final product for OSS. [ABSTRACT FROM AUTHOR]

Aptamers are short oligonucleotides isolated in vitro from randomized libraries that can bind to specific molecules with high affinity, and offer a number of advantages relative to antibodies as biorecognition elements in biosensors. However, it remains difficult and labor‐intensive to develop aptamer‐based sensors for small‐molecule detection. Here, we review the challenges and advances in the isolation and characterization of small‐molecule‐binding DNA aptamers and their use in sensors. First, we discuss in vitro methodologies for the isolation of aptamers, and provide guidance on selecting the appropriate strategy for generating aptamers with optimal binding properties for a given application. We next examine techniques for characterizing aptamer–target binding and structure. Afterwards, we discuss various small‐molecule sensing platforms based on original or engineered aptamers, and their detection applications. Finally, we conclude with a general workflow to develop aptamer‐based small‐molecule sensors for real‐world applications. [ABSTRACT FROM AUTHOR]

This Minireview presents recent important homogenous aerobic oxidative reactions which are assisted by electron transfer mediators (ETMs). Compared with direct oxidation by molecular oxygen (O2), the use of a coupled catalyst system with ETMs leads to a lower overall energy barrier via stepwise electron transfer. This cooperative catalytic process significantly facilitates the transport of electrons from the reduced form of the substrate‐selective redox catalyst (SSRCred) to O2, thereby increasing the efficiency of the aerobic oxidation. In this Minireview, we have summarized the advances accomplished in recent years in transition‐metal‐catalyzed as well as metal‐free aerobic oxidations of organic molecules in the presence of ETMs. In addition, the recent progress of photochemical and electrochemical oxidative functionalization using ETMs and O2 as the terminal oxidant is also highlighted. Furthermore, the mechanisms of these transformations are showcased. [ABSTRACT FROM AUTHOR]

Azolium cumulenolates are a special type of intermediates in N‐heterocyclic carbene catalysis. They contain elongated linear structures with three contiguous C=C bonds and sterically unhindered α‐carbon atoms. These structural features make it difficult to develop enantioselective reactions for these intermediates. Here we disclose the first carbene‐catalyzed highly enantioselective addition reactions of azolium cumulenolates. The reaction starts with alkynals as the precursors for azolium cumulenolate intermediates that undergo enantioselective addition to activated ketones. From the same set of substrates, both allene and spirooxindole products can be obtained with high yields and excellent enantioselectivities. The allene moieties in our optically enriched products carry rich reactivities and can be transformed to diverse molecules. The spirooxindole scaffolds in our products are important structural motifs in natural products and medicines. [ABSTRACT FROM AUTHOR]

Here, we report a facile method to synthesize a series of macrocycles with different conformations. The planar macrocycle dimer (1), twisted macrocycle trimer (2) and "figure‐eight" tetramer (3) are clearly elucidated by X‐ray single‐crystal analysis, in which the electron‐rich phenanthrene units offer the possibility of supramolecular assembly. As expected, in the solid state, 1 and 3 assemble into a columnar stack and an interlocking dimer, respectively, via π–π interactions between the phenanthrene units. Compared to the rigid conformation of dimer 1, the structure of tetramer 3 is more flexible due to its enlarged ring size. 3 can deform from a figure‐eight into a boat‐shaped geometry to host a planar electron‐deficient guest using its electron‐rich phenanthrene units. When assembled with spherical electron‐deficient C60, interestingly, 3 further undergoes a conformational transformation from a figure‐eight to a belt shape in order to host C60. These supramolecular assembly behaviors of 3 demonstrate that it is an adaptable macrocyclic host for both planar molecules and fullerenes. [ABSTRACT FROM AUTHOR]

Cyclodextrin poly‐functionalization has fueled progress in their use in multiple applications such as enzyme mimicry, but also in the polymer sciences, luminescence, as sensors or for biomedical applications. However, regioselective access to a given pattern of functions on β‐cyclodextrin is still very limited. We uncover a new orienting group, the thioacetate, that expands the toolbox available for cyclodextrin poly‐hetero‐functionalization using diisobutylaluminum hydride (DIBAL‐H) promoted debenzylation. The usefulness of this group is illustrated in the first synthesis of a precisely hepta‐hetero‐functionalized β‐cyclodextrin. By way of comparison, a random hepta‐functionalization would give 117655 different molecules. This synthesis is not simply the vain quest for the Holy Grail of CD hetero‐functionalization, but it illustrates the versatility of the DIBAL‐H oriented hetero‐functionalization strategy, opening the way to a multitude of useful functionalization patterns for new practical applications. [ABSTRACT FROM AUTHOR]