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Plastic pollution is worsening the living conditions on Earth, primarily due to the toxicity and stability of non‐biodegradable plastics (NBPs). Photocatalytic cracking of NBPs is emerging as a promising way to cleave inert C−C bonds and abstract the carbon atoms from these wastes into valuable chemicals and fuels. However, controlling these processes is a huge challenge, ascribed to the complicated reactions of various NBPs. Herein, we summarize recent advances in the CO2 and carbon‐radical‐mediated photocatalytic cracking of NBPs, with an emphasis on the pivotal intermediates. The CO2‐mediated cracking proceeded with indiscriminate C−H/C−C bond cleavage of NBPs and tandem photoreduction of CO2, while carbon‐radical‐mediated cracking was realized by the prior activation of C−H bonds for selective C−C bond cleavage of NBPs. Catalytic generation and conversion of different intermediates greatly depend on the kinds of active species and the structure of photocatalysts under irradiation. Meanwhile, the fate of a specific intermediate is compared with small molecule activation to reveal the key problems in the cracking of NBPs. Finally, the challenges and potential directions are discussed to improve the overall efficiency in the photocatalytic cracking of NBPs. [ABSTRACT FROM AUTHOR]

Expanding the diversity of multi‐macrocyclic nanocarbons, particularly those with all‐benzene scaffolds, represents intriguing yet challenging synthetic tasks. Complementary to the existing synthetic approaches, here we report an efficient and modular post‐functionalization strategy that employs iridium‐catalyzed C−H borylation of the highly strained meta‐cycloparaphenylenes (mCPPs) and an mCPP‐derived catenane. Based on the functionalized macrocyclic synthons, a number of novel all‐benzene topological structures including linear and cyclic chains, polycatenane, and pretzelane have been successfully prepared and characterized, thereby showcasing the synthetic utility and potential of the post‐functionalization strategy. [ABSTRACT FROM AUTHOR]

Sb2S3 has been extensively used as light absorber for photoelectrochemical cell. However, its p‐type nature may result in the formation of Schottky junction with substrates, thus hindering the collection of photogenerated holes. Herein, an ultrathin CuxS layer is successfully engineered as the bottom junction for Sb2S3 for the first time. Capitalizing on its impressive electrical properties and superior optical properties, the CuxS layer exhibits a high work function of 4.90 eV, which causes the upward band bending of p‐type Sb2S3, forming a hole‐transparent structure with ohmic contact. The transparency of the ultrathin CuxS layer enables back‐illumination of the Sb2S3/CuxS platform, facilitating the integration of intricate catalyst layers for photoelectrochemical transformation. When modified with Pt nanoparticles, the photocurrent density reaches −5.38 mA cm−2 at 0 V vs. RHE, marking a fourfold increase compared to the photocathode without CuxS layer. When introducing a molecular hybrid TC‐CoPc@carbon black, a remarkable average photocurrent density of −0.44 mA cm−2 at the overpotential of 0 V is obtained for CO2 reduction reaction, while the photocurrent density is less than −0.03 mA cm−2 without CuxS. [ABSTRACT FROM AUTHOR]

The replacement of a CC unit with an isoelectronic BN unit in aromatic systems can give rise to molecules and materials with fascinating properties. We report here the synthesis, characterization, and reactivity of a 1,4,2,3‐diazadiborole species, 2, featuring an unprecedented 6π‐aromatic BN‐heterocyclic moiety that is isoelectronic to cyclopentadienide (Cp−). Bearing an unsymmetrical B=B entity, 2 exhibits reactivity toward oxidants, protic reagents, electrophiles, and unsaturated substrates. This reactivity facilitates the synthesis of a variety of novel mono‐ and bicyclic organoboron derivatives through mechanisms including ring retention, cleavage/recombination, annulation, and expansion. These findings reveal innovative synthetic routes to BN‐embedded aromatic compounds via desymmetrization, affording unique building blocks for synthetic chemistry. [ABSTRACT FROM AUTHOR]

Near infrared (NIR) emitter with circularly polarized phosphorescence (CPP), known as NIR CPP, has emerged as a key part in the research of cutting‐edge luminescent materials. However, it remains a challenge to obtain nanoclusters with NIR CPP activity. Here, we propose an asymmetric transformation approach to efficiently synthesize two pairs of chiral silver nanoclusters (R/S‐Ag29 and R/S‐Ag16) using an achiral Ag10 nanocluster as starting material in the presence of different concentration chiral inducer (R/S)‐1,1′‐binaphthyl‐2,2′‐diyl hydrogenphosphate (R/S‐BNP). R/S‐Ag29, formed in the low‐concentration R/S‐BNP, exhibits a unique kernel‐shell structure consisting of a distorted Ag13 icosahedron and an integrated cage‐like organometallic shell with a C3 symmetry, and possesses a superatomic 6‐electron configuration (1S2|1P4). By contrast, R/S‐Ag16, formed in the high‐concentration R/S‐BNP, features a sandwich‐like pentagram with AgI‐pure kernel. Profiting from the hierarchically chiral structures and superatomic kernel‐dominated phosphorescence, R/S‐Ag29 exhibits infrequent CPP activity in the second near‐infrared (975 nm) region, being the first instance of NIR‐II CPP observed among CPL‐active metal nanoclusters. This study presents a new approach to reduce the difficulty of de novo synthesis for chiral silver nanomaterials, and facilitates the design of CPP‐active superatomic nanoclusters in NIR region. [ABSTRACT FROM AUTHOR]

Herein, two atomically precise silver nanoclusters, Ag54 and Ag33, directed by inner anion templates (CrO42− and/or Cl−), are initially isolated as a mixed phase from identical reactants across a wide temperature range (20–80 °C). Interestingly, fine‐tuning the reaction temperature can realize pure phase synthesis of the two nanoclusters; that is, a metastable Ag54 is kinetically formed at a low temperature (20 °C), whereas such a system is steered towards a thermodynamically stable Ag33 at a relatively high temperature (80 °C). Electrospray ionization mass spectrometry illustrates that the stability of Ag33 is superior to that of Ag54, which is further supported by density functional theory calculations. Importantly, the difference in structural stability can influence the pathway of 1,4‐bis(pyrid‐4‐yl)benzene induced transformation reaction starting from Ag54 and Ag33. The former undergoes a dramatic breakage‐reorganization process to form an Ag31 dimer (Ag31), while the same product can be also achieved from the latter following a noninvasive ligand exchange process. Both the Ag54 and Ag33 have the potential for further remote laser ignition applications. This work not only demonstrates how temperature controls the isolation of a specific phase, but also sheds light on the structural transformation pathway of nanoclusters with different stability. [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]

"Improbable" rotaxanes consisting of interlocked conjugated components represent non‐trivial synthetic targets, not to mention those with all‐benzene scaffolds. Herein, a modular synthetic strategy has been established using an isolable azo‐linked pre‐rotaxane as the core module, in which the azo group functions as a tracelessly removable template to direct mechanical bond formations. Through versatile connections of the pre‐rotaxane and other customizable modules, [2]‐ and [3]rotaxanes derived from all‐benzene scaffolds have been accomplished, demonstrating the utility and potential of the synthetic design for all‐benzene interlocked supramolecules. [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]

Polyoxometalates (POMs) represent crucial intermediates in the formation of insoluble metal oxides from soluble metal ions, however, the rapid hydrolysis‐condensation kinetics of MoVI or WVI makes the direct characterization of coexisted molecular species in a given medium extremely difficult. Silver nanoclusters have shown versatile capacity to encapsulate diverse POMs, which provides an alternative scene to appreciate landscape of POMs in atomic precision. Here, we report a thiacalix[4]arene protected silver nanocluster (Ag72b) that simultaneously encapsulates three kinds of molybdates (MoO42−, Mo6O228− and Mo7O258−) in situ transformed from classic Lindqvist Mo6O192−, providing more deep understanding on the structural diversity and condensation growth route of POMs in solution. Ag72b is the first silver nanocluster trapping so many kinds of molybdates, which in turn exert collective template effect to aggregate silver atoms into a nanocluster. The post‐reaction of Ag72b with AgOAc or PhCOOAg produces a discrete Ag24 nanocluster (Ag24a) or an Ag28 nanocluster based 1D chain structure (Ag28a), respectively. Moreover, the post‐synthesized Ag28a can be utilized as potential ignition material for further application. This work not only provides an important model for unlocking dynamic features of POMs at atom‐precise level but also pioneers a promising approach to synthesize silver nanoclusters from known to unknown. [ABSTRACT FROM AUTHOR]

This report unveils an advancement in the formation of a Lewis superacid (LSA) and an organic superbase by the geometrical deformation of an organoboron species towards a T‐shaped geometry. The boron dication [2]2+ supported by an amido diphosphine pincer ligand features both a large fluoride ion affinity (FIA>SbF5) and hydride ion affinity (HIA>B(C6F5)3), which qualifies it as both a hard and soft LSA. The unusual Lewis acidic properties of [2]2+ are further showcased by its ability to abstract hydride and fluoride from Et3SiH and AgSbF6 respectively, and effectively catalyze the hydrodefluorination, defluorination/arylation, as well as reduction of carbonyl compounds. One and two‐electron reduction of [2]2+ affords stable boron radical cation [2]⋅+ and borylene 2, respectively. The former species has an extremely high spin density of 0.798e at the boron atom, whereas the latter compound has been demonstrated to be a strong organic base (calcd. pKBH+ (MeCN)=47.4) by both theoretical and experimental assessment. Overall, these results demonstrate the strong ability of geometric constraining to empower the central boron atom. [ABSTRACT FROM AUTHOR]

High‐valent iron‐oxo species are appealing for conducting O−O bond formation for water oxidation reactions. However, their high reactivity poses a great challenge to the dissection of their chemical transformations. Herein, we introduce an electron‐rich and oxidation‐resistant ligand, 2‐[(2,2′‐bipyridin)‐6‐yl]propan‐2‐ol to stabilize such fleeting intermediates. Advanced spectroscopies and electrochemical studies demonstrate a high‐valent FeV(O) species formation in water. Combining kinetic and oxygen isotope labelling experiments and organic reactions indicates that the FeV(O) species is responsible for O−O bond formation via water nucleophilic attack under the real catalytic water oxidation conditions. [ABSTRACT FROM AUTHOR]

The activation of the α‐C−H bond of ketones typically requires an amine and a directing group to guide the reaction selectivity in amine‐catalysis carbonyl chemistry. For an α‐C−H bond activation of ketone, directing groups are also required to control the reaction selectivity. Reported herein is the first α‐alkylation of cyclic ketones in the absence of an amine catalyst and directing group. 1H NMR, XPS, EPR studies and DFT calculations indicate that an α‐carbon radical intermediate is formed through direct and selective activation of the inert α‐C−H bond of ketones chelating on the surface of colloidal quantum dots (QDs). Such an interaction is essential for weakening the C−H bond, as exemplified, using CdSe QDs as the sole photocatalyst to execute α‐C−H alkylation of cyclic ketones under visible‐light irradiation. Without an amine catalyst and directing group, the high step‐ and atom‐economy transformation under redox‐neutral condition opens a new way for α‐C−H functionalization of ketones in carbonyl chemistry. [ABSTRACT FROM AUTHOR]

Graphdiyne (GDY) with a direct band gap, excellent carrier mobility and uniform pores, is regarded as a promising photocatalytic material for solar energy conversion, while the research on GDY in photocatalysis is a less developed field. Herein, the distinctive structure, adjustable band gap, and electronic properties of GDY for photocatalysis is firstly summarized. The construction and progress of GDY‐based photocatalysts for solar energy conversion, including H2 evolution reaction (HER), CO2 reduction reaction (CO2RR) and N2 reduction reaction (NRR) are then elaborated. At last, the challenges and perspectives in developing GDY‐based photocatalysts for solar fuel production are discussed. It is anticipated that a timely Minireview will be helpful for rapid progress of GDY in solar energy conversion. [ABSTRACT FROM AUTHOR]

We describe an aromatic amide skeleton for manipulation of triplet excited states toward bright long‐lived blue phosphorescence. Spectroscopic studies and theoretical calculations demonstrated that the aromatic amides can promote strong spin‐orbit coupling between (π,π*) and the bridged (n,π*) states, and enable multiple channels to populate the emissive 3(π,π*), as well as facilitate robust hydrogen bonding with polyvinyl alcohol to suppress non‐radiative relaxations. Isolated inherent deep‐blue (0.155, 0.056) to sky‐blue (0.175, 0.232) phosphorescence with high quantum yields (up to 34.7 %) in confined films are achieved. The blue afterglow of the films can last for several seconds and are showcased in information display, anti‐counterfeiting, and white light afterglow. Owing to the high population of 3(π,π*) states, the smart aromatic amide skeleton provides an important molecular design prototype to manipulate triplet excited states for ultralong phosphorescence with various colors. [ABSTRACT FROM AUTHOR]

Represented herein is the first example of N‐radical generation direct from N−H bond activation under mild and redox‐neutral conditions. The in situ generated N‐radical intercepts a reduced heteroarylnitrile/aryl halide for C−N bond formation under visible‐light irradiation of quantum dots (QDs). A series of aryl and alkylamines with heteroarylnitriles/aryl halides exhibit high efficiency, site‐selectivity and good functional‐group tolerance. Moreover, consecutive C−C and C−N bond formation using benzylamines as substrates is also achieved, producing N‐aryl‐1,2‐diamines with H2 evolution. The redox‐neutral conditions, broad substrate scope, and efficiency of N‐radical formation are advantageous for organic synthesis. [ABSTRACT FROM AUTHOR]

A new way to form fluorenones via the direct excitation of substrates instead of photocatalyst to activate the C(sp2)−H bond under redox‐neutral condition is reported. Our design relies on the photoexcited aromatic aldehyde intermediates that can be intercepted by cobaloxime catalyst through single electron transfer for following β‐H elimination. The generation of acyl radical and successful interception by a metal catalyst cobaloxime avoid the use of a photocatalyst and stoichiometric external oxidants, affording a series of highly substituted fluorenones, including six‐membered ketones, such as xanthone and thioxanthone derivatives in good to excellent yields, and with hydrogen as the only byproduct. This catalytic system features a readily available metal catalyst, mild reaction conditions and broad substrate scope, in which sunlight reaction and scale‐up experiments by continuous‐flow approach make the new methodology sustainable and amenable for potentially operational procedures. [ABSTRACT FROM AUTHOR]

A direct strategy for the difunctionalization of alkenes, with acylation occurring at the more substituted alkene position, would be attractive for complex ketone synthesis. We report herein a reaction driven by a single photocatalyst that enables α‐acylation in this way with the introduction of a fluoromethyl, alkyl, sulfonyl or thioether group at the β‐position of the alkene with high chemo‐ and regioselectivity under extremely mild conditions. Crucial to the success of this method are rate differences in the kinetics of radical generation through single‐electron transfer (SET) between different radical precursors and the excited photocatalyst (PC*). Thus, the β‐position of the alkene is first occupied by the group derived from the radical precursor that can be generated most readily, and α‐keto acids could be used as an electrophilic reagent for the α‐acylation of alkenes. [ABSTRACT FROM AUTHOR]

The synthesis of benzofurans from readily accessible sulfur ylides and ortho‐hydroxy aryl alkynes is reported. The transformation proceeds through an isomerization/nucleophilic addition/cyclization/aromatization cascade. The substrate scope is very general with respect to both reactants and the products are afforded in 43–94% yield under conditions which are catalyst‐free and additive‐free. [ABSTRACT FROM AUTHOR]

The composition of protection monolayer exerts great influence on the molecular and electronic structures of atomically precise monolayer protected metal nanoclusters. Four isostructural Ag/cyanurate/phosphine metallamacrocyclic monolayer protected Ag22 nanoclusters are synthesized by kinetically controlled in‐situ ligand formation‐driven strategy. These eight‐electron superatomic silver nanoclusters feature an unprecedented interfacial bonding structure with diverse E‐Ag (E=O/N/P/Ag) interactions between the Ag13 core and metallamacrocyclic monolayer, and displays thermally activated delayed fluorescence (TADF), benefiting from their distinct donor‐acceptor type electronic structures. This work not only unmasks a new core‐shell interface involving cyanurate ligand but also underlines the significance of high‐electron‐affinity N‐heterocyclic ligand in synthesizing TADF metal nanoclusters. This is the first mixed valence Ag0/I nanocluster with TADF characteristic. [ABSTRACT FROM AUTHOR]

The complexation of dibromo‐fluorenylborane (FluH‐BBr2) with bulky bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene (IPr) afforded N‐heterocyclic carbene (NHC) borane adduct 1, which could be subsequently dehydrobrominated by smaller 1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene (IPr2Me2) to give the alkylideneborane‐NHC complex 2. Species 2 readily binds with potassium ion to form a potassium alkylideneborane complex 3 through exclusive cation‐π interactions. [ABSTRACT FROM AUTHOR]

Herein, cobaloxime is used for the first time as a catalyst for the synthesis of phosphorylated heteroaromatics, which is an intriguing and versatile functional motif. With visible‐light irradiation, cobaloxime not only oxidizes phosphine oxides to form phosphorus radicals (P‐radicals) for a subsequent reaction with radical acceptor isocyanides or heteroaromatics, but also combines the radical intermediate with β‐H elimination, thereby producing phosphorylated heteroaromatics with only H2 or CH4 as byproduct. Phosphine oxides with dialkyl, alkylaryl, and diaryl substituents could be directly transformed into phosphorylated phenanthridines, benzothiazoles, isoquinolines, and common heteroaromatics. This catalytic system features extremely mild conditions, broad substrate scope and good to excellent yields. Scale‐up reaction and sunlight reaction show the great application potential in the green synthesis of important organophosphorus chemicals. [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]

Being isoelectronic with alkynes, iminoboranes with a polar B≡N triple bond have been exclusively investigated as a potent 1,2‐dipole in synthetic chemistry. Herein, we disclose the unprecedented reactivity of aryliminoboranes via the BNCC π conjugation, namely hetero‐enyne behavior. This allows for facile dearomative Diels–Alder‐like reactions of aryliminoboranes with aldehydes. This cycloaddition features mild conditions, is catalyst‐free, and has a broad substrate scope and good functional group tolerance. Kinetic and computational studies reveal its second‐order reaction and concerted cyclization mechanism. This report unveils new synthetic application of iminoboranes beyond their classical reaction patterns. [ABSTRACT FROM AUTHOR]

Colloidal quantum dots (QDs) consisting of precious‐metal‐free elements show attractive potentials towards solar‐driven CO2 reduction. However, the inhibition of hydrogen (H2) production in aqueous solution remains a challenge. Here, we describe the first example of a carbon–carbon (C−C) coupling reaction to block the competing H2 evolution in photocatalytic CO2 reduction in water. In a specific system taking ZnSe QDs as photocatalysts, the introduction of furfural can significantly suppress H2 evolution leading to CO evolution with a rate of ≈5.3 mmol g−1 h−1 and a turnover number (TON) of >7500 under 24 h visible light. Meanwhile, furfural is upgraded to the self‐coupling product with a yield of 99.8 % based on the consumption of furfural. Mechanistic insights show that the reductive furfural coupling reaction occurs on surface Zn‐sites to consume electrons and protons originally used for H2 production, while the CO formation pathway at surface anion vacancies from CO2 remains. [ABSTRACT FROM AUTHOR]

Thiacalix[4]arenes have emerged as a family of macrocyclic ligands to protect metal nanoparticles, but it remains a great challenge to solve the mystery of their structures at the atomic level, especially for those larger than 2 nm. Here, we report the largest known mixed‐valence silver nanocluster [Ag155(CyS)40(TC4A)5Cl2] (Ag155) protected by deprotonated cyclohexanethiol (CySH) and macrocyclic ligand p‐tert‐butylthiacalix[4]arene (H4TC4A). Its single‐crystal structure consists of a metallic core of four concentric shells, Ag13@Ag42@Ag30@Ag70, lined with a organic skin of 40CyS− and 5TC4A4− and 2Cl−. Ag155 manifests an unusual pseudo‐5‐fold symmetry dictated by the intrinsic metal atom packing and the regioselective distribution of mixed protective ligands. This work not only reveals a macrocyclic ligand effect on the formation of a large silver nanocluster, but also provides a new structural archetype for comprehensively perceiving their interface and metal kernel structures. [ABSTRACT FROM AUTHOR]

Stepwise assembly starting from a preassembled metalloligand is a promising approach to obtain otherwise unattainable silver nanoclusters, but hard to be intrinsically identified due to the lack of convincing evidence to justify such a process. Herein, hexagonal and rectangular Ag18 nanoclusters are constructed from the [Mo2O5(PTC4A)2]6− (H4PTC4A=p‐phenyl‐thiacalix[4]arene) metalloligand through stepwise assembly. The formation of the metalloligand is confirmed by electrospray ionization mass spectrometry, then assembled with silver ions to form two geometrically different Ag18 nanoclusters in different solvents. The cyclization from the metalloligand to [(Mo2O5PTC4A)6]12− can be realized without alcohols and otherwise blocked by them. The installation of this metalloligand not only provides comprehensive understanding of how the solvents regulate the silver nanocluster structures, but also brings new insights for the controllable ligand metallization and subsequent condensation. [ABSTRACT FROM AUTHOR]

Although Schleyer's computations in 1979 predicted that the ground state of the parent diborirane features a planar‐tetracoordinate carbon atom (anti van't Hoff–Le Bel geometry), this work demonstrates that substitution of C coupled with N‐heterocyclic carbene (NHC) coordination provides access to isolable diborirane derivatives 3 and 4 with van't Hoff–Le Bel geometry. Species 3 and 4 are isoelectronic with cyclopropane and the highly strained B2C rings feature 2c–2e bent σ bonds. Consequently, the B−B and B−C bonds in 3 are cleaved in the presence of hydride, proton, and chalcogens. The former two reactions gave NHC‐coordinated fluorenyldihydridoborane 5 and dichlorofluorenylborane 6, respectively, whereas the latter transformations afforded novel thiaborirane 8 and selenaborirane 9. In addition, transfer hydrogenation of 3 with ammonia borane (H3N⋅BH3) led to the formation of (μ‐hydrido)diborane 7 via selective cleavage of the B−B bond. These reactivities show potential for their future application in organic synthesis. [ABSTRACT FROM AUTHOR]

Site‐selective N‐1 and C‐3 arylation of indole has been sought after because of the prevalent application of arylindoles and the intricate reactivities associated with the multiple sites of the N‐unsubstituted indole. Represented herein is the first regioselective heteroarylation of indole via a radical–radical cross‐coupling by visible‐light irradiation. Steady and time‐resolved spectroscopic and computational studies revealed that the hydrogen‐bonding interaction of organic base and its conjugated acid, namely with indole and heteroarylnitrile, determined the reaction pathway, which underwent either proton‐coupled electron‐transfer or energy‐transfer for the subsequent radical–radical cross‐coupling, leading to the regioselective formation of C‐3 and N‐1 heteroarylation of indoles, respectively. The parallel methodologies for regioisomeric N‐1 and C‐3 heteroaryl indoles with good functional group compatibility could be applied to large‐scale synthesis and late‐stage derivatization of bioactive compounds under extremely mild reaction conditions. [ABSTRACT FROM AUTHOR]

A fully conjugated figure‐of‐eight nanohoop is presented with facile synthesis. The molecule's lemniscular skeleton features the combination of two strained oligoparaphenylene loops and a flexible cyclooctatetrathiophene core. Its rigid yet guest‐adaptive cavities enable the formation of the peanut‐like 1:2 host–guest complexes with C60 or C70, which have been confirmed by X‐ray crystallography and characterized in solution. Further computational studies suggest notable geometric variations and non‐covalent interactions of the cavities upon binding with different fullerenes, as well as overall conjugation comparable to cycloparaphenylenes. [ABSTRACT FROM AUTHOR]

As one of the most ubiquitous bulk reagents available, the intrinsic chemical inertness of tetrahydrofuran (THF) makes direct and site‐selective C(sp3)−H bond activation difficult, especially under redox neutral condition. Here, we demonstrate that semiconductor quantum dots (QDs) can activate α‐C−H bond of THF via forming QDs/THF conjugates. Under visible light irradiation, the resultant alkoxyalkyl radical directly engages in radical cross‐coupling with α‐amino radical from amino C−H bonds or radical addition with alkene or phenylacetylene, respectively. In contrast to stoichiometric oxidant or hydrogen atom transfer reagents required in previous studies, the scalable benchtop approach can execute α‐C−H bond activation of THF only by a QD photocatalyst under redox‐neutral condition, thus providing a broad of value added chemicals starting from bulk THFs reagent. [ABSTRACT FROM AUTHOR]

1,4‐Dicarbonyl compounds are intriguing motifs and versatile precursors in numerous pharmaceutical molecules and bioactive natural compounds. Direct incorporation of two carbonyl groups into a double bond at both ends is straightforward, but also challenging. Represented herein is the first example of 1,2‐dicarbonylation of alkenes by photocatalysis. Key to success is that N(n‐Bu)4+ not only associates with the alkyl anion to avoid protonation, but also activates the α‐keto acid to undergo electrophilic addition. The α‐keto acid is employed both for acyl generation and electrophilic addition. By tuning the reductive and electrophilic ability of the acyl precursor, unsymmetric 1,4‐dicarbonylation is achieved for the first time. This metal‐free, redox‐neutral and regioselective 1,2‐dicarbonylation of alkenes is executed by a photocatalyst for versatile substrates under extremely mild conditions and shows great potential in biomolecular and drug molecular derivatization. [ABSTRACT FROM AUTHOR]

A bis(pyridyl)amine‐bipyridine‐iron(II) framework (Fe(BPAbipy)) of complexes 1–3 is reported to shed light on the multistep nature of CO2 reduction. Herein, photocatalytic conversion of CO2 to CO even at low CO2 concentration (1 %), together with detailed mechanistic study and DFT calculations, reveal that 1 first undergoes two sequential one‐electron transfer affording an intermediate with electron density on both Fe and ligand for CO2 binding over proton. The following 2 H+‐assisted Fe‐CO formation is rate‐determining for selective CO2‐to‐CO reduction. A pendant, proton‐shuttling α‐OH group (2) initiates PCET for predominant H2 evolution, while an α‐OMe group (3) cancels the selectivity control for either CO or H2. The near‐unity selectivity of 1 and 2 enables self‐sorting syngas production at flexible CO/H2 ratios. The unprecedented results from one kind of molecular catalyst skeleton encourage insight into the beauty of advanced multi‐electron and multi‐proton transfer processes for robust CO2RR by photocatalysis. [ABSTRACT FROM AUTHOR]

Axially chiral indoline‐based scaffolds are virtually universal in biological and pharmaceutical compounds. In this study, we demonstrate the Rh‐catalyzed asymmetric [2 + 2 + 2] cycloaddition of 1,6‐enynes with steric hindered N‐alkynyl indoles, which enables simultaneous construction of both axial and central chirality, containing a quaternary carbon center, in one step. Notable features of these reactions include excellent chemo‐, regio‐, diastereo‐ and enantioselectivity, 100% atom‐economy, easily available SEGPHOS ligand, and mild conditions. [ABSTRACT FROM AUTHOR]

An asymmetric multicomponent, interrupted Kinugasa allylic alkylation (IKAA) reaction has been developed with a synergistic Cu‐catalyzed Kinugasa system and a Pd‐catalyzed allylic alkylation reaction. This unprecedented reaction provides in high yields and with high stereoselectivity a synthesis of α‐quaternary chiral β‐lactams, which cannot be produced with existing synthetic methods. Stereoselective coupling of two catalytic amounts of transient organometallic intermediates formed in situ is an important feature of this reaction. [ABSTRACT FROM AUTHOR]

Direct allylic C−H thiolation is straightforward for allylic C(sp3)−S bond formation. However, strong interactions between thiol and transition metal catalysts lead to deactivation of the catalytic cycle or oxidation of sulfur atom under oxidative condition. Thus, direct allylic C(sp3)−H thiolation has proved difficult. Represented herein is an exceptional for direct, efficient, atom‐ and step‐economic thiolation of allylic C(sp3)−H and thiol S−H under visible light irradiation. Radical trapping experiments and electron paramagnetic resonance (EPR) spectroscopy identified the allylic radical and thiyl radical generated on the surface of photocatalyst quantum dots (QDs). The C−S bond formation does not require external oxidants and radical initiators, and hydrogen (H2) is produced as byproduct. When vinylic C(sp2)−H was used instead of allylic C(sp3)−H bond, the radical‐radical cross‐coupling of C(sp2)−H and S−H was achieved with liberation of H2. Such a unique transformation opens up a door toward direct C−H and S−H coupling for valuable organosulfur chemistry. [ABSTRACT FROM AUTHOR]

A copper(I)‐catalyzed asymmetric, three‐component interrupted Kinugasa reaction has been developed. Diverse chiral sulfur‐containing chiral β‐lactams with two consecutive stereogenic centers were synthesized in one step from readily available starting materials in good yields and with excellent diastereo‐ and enantioselectivity. The key is the interception of in situ formed chiral four membered copper(I) enolate intermediate with sulfur electrophiles. [ABSTRACT FROM AUTHOR]

Herein, we report a 78‐nuclei silver nanocluster (NC) [Ag78(iPrPhS)30(dppm)10Cl10]4+ (SD/Ag78a; dppm=bis‐(diphenylphosphino)methane) that was synthesized through a one‐pot reaction using [Ag(pz)]n as precursor (Hpz=pyrazole) and further characterized by X‐ray crystallography. SD/Ag78a shows a core–shell structure comprised of an all‐metallic Ag53 kernel surrounded by an Ag25 discontinuous metal–organic shell. The Ag53 kernel is an Ag13 Ino decahedron encaged by an Ag40 drum‐like shell, while the Ag25 shell consists of two Ag10S10P10Cl5 rings and five S‐Ag‐S staples. Three types of ligands regioselectively cap on the surface of the Ag78 NC, forming diverse metal–ligand interfacial structures. The NC is a closed‐shell 34‐electron superatom with +4 charge state and shows highly featured molecule‐like absorption spectra in the UV/Vis region with a maximum around 493 nm. The rhombic superlattice assembled from SD/Ag78a through intercluster C−H⋅⋅⋅π interactions can be formed by a simple drop‐casting treatment. [ABSTRACT FROM AUTHOR]

[FeFe]‐hydrogenase ([FeFe]‐H2ase) mimics, inspired by hydrogenases in nature, have emerged as an important class of molecular catalysts toward hydrogen (H2) evolution. Herein, a per‐6‐thiol‐cyclodextrin (CDSH) engineered [FeFe]‐H2ase mimic/CdSe quantum dot (QD) assembly is established for effective photocatalytic H2 evolution. In the assembly, CDSH is first anchored on CdSe QDs via the strong multidentate Cd‐thiol coordination. Then, [FeFe]‐H2ase mimic is assembled on the QD surface via the host–guest supramolecular interaction between the hydrophobic cavity of cyclodextrin (CD) and the adamantyl (AD) group of [FeFe]‐H2ase mimic. In neutral aqueous solution of isopropanol, the Fe2S2‐AD/CDSH/CdSe assembly exhibits a turnover number (TON) of 1.12 × 105 (based on Fe2S2‐AD) under visible light, which is about 12‐fold to the corresponding system without CDSH. Mechanistic insights indicate that the CDSH can not only prevent the aggregation of QDs in acidic conditions, but also balance the interfacial charge (electron and hole) transfer to avoid the photocorrosion of QDs, thereby giving the highest TON of H2 photogeneration based on [FeFe]‐H2ase mimics up to date. [ABSTRACT FROM AUTHOR]

Hypoxia is a parameter related to many diseases. Ratiometric hypoxia probes often rely on a combination of an O2‐insensitive fluorophore and an O2‐sensitive phosphor in a polymer matrix, which require high cost and multi‐step synthesis of transition metal complexes. The two‐chromophore hypoxia probes encounter unfavorable energy transfer processes and different stabilities of the chromophores. Reported herein is a pure organic ratiometric hypoxia nanoprobe, assembled by a monochromophore, naphthalimide ureidopyrimidinone (BrNpA‐UPy), bridged by a bis‐UPy‐functionalized benzyl skeleton. The joint factors of quadruple hydrogen bonding, the rigid backbone of UPy, and bromine substitution of the naphthalimide derivative facilitate bright phosphorescence (ΦP=7.7 %, τP=3.2 ms) and fluorescence of the resultant nanoparticles (SNPs) at room temperature, which enable accurate, ratiometric, sensitive oxygen detection (Ksv=189.6 kPa−1) in aqueous solution as well as in living HeLa cells. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion: We report herein a practical approach for synthesis of an electrophilic trifluoroethylthiolation reagent PhSO2SCH2CF3 (1) from easily available materials. The reaction proceeded through a protonation and nucleophilic substitution cascade of the in situ formed trifluorodiazoethane. This bench‐stable reagent could easily be applied to introduce trifluoroethylthio group into small organic molecules. [ABSTRACT FROM AUTHOR]

Unprecedented double S2− templated Ag27 clusters have been stabilized by 5,10,15,20‐tetra(4‐pyridyl)porphyrin (TPyP‐H2) ligands to afford a robust 2D metal–organic framework (Ag27‐MOF). This silver cluster‐assembled material serves as a highly efficient heterogeneous catalyst for the cyclization of both terminal and internal propargylamines with CO2 under atmospheric pressure. Density functional theory (DFT) calculations illustrate that the high catalytic activity and broad substrate scope are attributable to the saddle‐shaped metallic node in Ag27‐MOF, which features an accessible platform with high‐density silver atoms as π‐Lewis acid sites for activating C≡C triple bonds. As a result, different sterically hindered alkyne substrates can be effectively activated through π‐interactions with these cationic silver centers. [ABSTRACT FROM AUTHOR]

Inspired by the natural [NiFe]‐H2ase, we designed mimic 1, (dppe)Ni(μ‐pdt)(μ‐Cl)Ru(CO)2Cl to realize effective H2 evolution under photocatalytic conditions. However, a new species 2 was captured in the course of photo‐, electro‐, and chemo‐ one‐electron reduction. Experimental studies of in situ IR spectroscopy, EPR, NMR, X‐ray absorption spectroscopy, and DFT calculations corroborated a dimeric structure of 2 as a closed‐shell, symmetric structure with a RuI center. The isolated dimer 2 showed the real catalytic role in photocatalysis with a benchmark turnover frequency (TOF) of 1936 h−1 for H2 evolution, while mimic 1 worked as a pre‐catalyst and evolved H2 only after being reduced to 2. The remarkably catalytic activity and unique dimer structure of 2 operated in photocatalysis unveiled a broad research prospect in hydrogenases mimics for advanced H2 evolution. [ABSTRACT FROM AUTHOR]

Three rigid and structurally simple heterocyclic stilbene derivatives, (E)‐3H,3′H‐[1,1′‐biisobenzofuranylidene]‐3,3′‐dione, (E)‐3‐(3‐oxobenzo[c] thiophen‐1(3H)‐ylidene)isobenzofuran‐1(3H)‐one, and (E)‐3H,3′H‐[1,1′‐bibenzo[c] thiophenylidene]‐3,3′‐dione, are found to fluoresce in their neat solid phases, from upper (S2) and lowest (S1) singlet excited states, even at room temperature in air. Photophysical studies, single‐crystal structures, and theoretical calculations indicate that large energy gaps between S2 and S1 states (T2 and T1 states) as well as an abundance of intra and intermolecular hydrogen bonds suppress internal conversions of the upper excited states in the solids and make possible the fluorescence from S2 excited states (phosphorescence from T2 excited states). These results, including unprecedented fluorescence quantum yields (2.3–9.6 %) from the S2 states in the neat solids, establish a unique molecular skeleton for achieving multi‐colored emissions from upper excited states by "suppressing" Kasha's rule. [ABSTRACT FROM AUTHOR]