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Dual‐atom catalysts (DACs) have been a new frontier in heterogeneous catalysis due to their unique intrinsic properties. The synergy between dual atoms provides flexible active sites, promising to enhance performance and even catalyze more complex reactions. However, precisely regulating active site structure and uncovering dual‐atom metal interaction remain grand challenges. In this review, we clarify the significance of the inter‐metal interaction of DACs based on the understanding of active center structures. Three diatomic configurations are elaborated, including isolated dual single‐atom, N/O‐bridged dual‐atom, and direct dual‐metal bonding interaction. Subsequently, the up‐to‐date progress in heterogeneous oxidation reactions, hydrogenation/dehydrogenation reactions, electrocatalytic reactions, and photocatalytic reactions are summarized. The structure‐activity relationship between DACs and catalytic performance is then discussed at an atomic level. Finally, the challenges and future directions to engineer the structure of DACs are discussed. This review will offer new prospects for the rational design of efficient DACs toward heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

Aryne insertions into the carbon‐iodine bond of heteroaryl iodides has been achieved for the first time. This novel reaction provides an efficient pathway for the synthesis of valuable building blocks 2‐iodoheterobiaryls from heteroaryl iodides and o‐silylaryl triflates in excellent regioselectivity. The copper(I) catalyst, which bears a N‐heterocyclic carbene (NHC) ligand, is essential to accomplish the reaction. Control reactions and DFT calculations indicate that the coordination of copper, as a Lewis acid, with nitrogen atoms of heteroaryl iodides mediates the insertion of arynes into heteroaryl carbon‐iodine bonds. [ABSTRACT FROM AUTHOR]

Metal single atoms (SAs) anchored in carbon support via coordinating with N atoms are efficient active sites to oxygen reduction reaction (ORR). However, rational design of single atom catalysts with highly exposed active sites is challenging and urgently desirable. Herein, an anion exchange strategy is presented to fabricate Fe‐N4 moieties anchored in hierarchical carbon nanoplates composed of hollow carbon spheres (Fe‐SA/N‐HCS). With the coordinating O atoms are substituted by N atoms, Fe SAs with Fe‐O4 configuration are transformed into the ones with Fe‐N4 configuration during the thermal activation process. Insights into the evolution of central atoms demonstrate that the SAs with specific coordination environment can be obtained by modulating in situ anion exchange process. The strategy produces a large quantity of electrochemical accessible site and high utilization rate of Fe‐N4. Fe‐SA/N‐HCS shows excellent ORR electrocatalytic performance with half‐wave potential of 0.91 V (vs. RHE) in 0.1 M KOH, and outstanding performance when used in rechargeable aqueous and flexible Zn‐air batteries. The evolution pathway for SAs demonstrated in this work offers a novel strategy to design SACs with various coordination environment and enhanced electrocatalytic activity. [ABSTRACT FROM AUTHOR]

Elucidating single‐atom effects on the fundamental properties of nanoparticles is challenging because single‐atom modifications are typically accompanied by appreciable changes to the overall particle's structure. Herein, we report the synthesis of a [Cu58H20PET36(PPh3)4]2+ (Cu58; PET: phenylethanethiolate; PPh3: triphenylphosphine) nanocluster—an atomically precise nanoparticle—that can be transformed into the surface‐defective analog [Cu57H20PET36(PPh3)4]+ (Cu57). Both nanoclusters are virtually identical, with five concentric metal shells, save for one missing surface copper atom in Cu57. Remarkably, the loss of this single surface atom drastically alters the reactivity of the nanocluster. In contrast to Cu58, Cu57 shows promising activity for click chemistry, particularly photoinduced [3+2] azide‐alkyne cycloaddition (AAC), which is attributed to the active catalytic site in Cu57 after the removal of one surface copper atom. Our study not only presents a unique system for uncovering the effect of a single‐surface atom modification on nanoparticle properties but also showcases single‐atom surface modification as a powerful means for designing nanoparticle catalysts. [ABSTRACT FROM AUTHOR]

An atroposelective Ir‐catalyzed dynamic kinetic resolution (DKR) of 2‐(quinolin‐8‐yl)benzaldehydes/1‐naphthaldehydes by transfer hydrogenative coupling of allyl acetate is disclosed. The allylation reaction takes place with simultaneous installation of central and axial chirality, reaching high diastereoselectivities and excellent enantiomeric excesses when ortho‐cyclometalated iridium‐DM‐BINAP is used as the catalyst. The racemization of the substrates occurs through a designed transient Lewis acid‐base interaction between the quinoline nitrogen atom and the aldehyde carbonyl group. [ABSTRACT FROM AUTHOR]

The asymmetric hydrophosphination of cyclopropenes with phosphines is of much interest and importance, but has remained hardly explored to date probably because of the lack of suitable catalysts. We report here the diastereo‐ and enantioselective hydrophosphination of 3,3‐disubstituted cyclopropenes with phosphines by a chiral lanthanocene catalyst bearing the C2‐symmetric 5,6‐dioxy‐4,7‐trans‐dialkyl‐substituted tetrahydroindenyl ligands. This protocol offers a selective and efficient route for the synthesis of a new family of chiral phosphinocyclopropane derivatives, featuring 100 % atom efficiency, good diastereo‐ and enantioselectivity, broad substrate scope, and no need for a directing group. [ABSTRACT FROM AUTHOR]

Triboraazabutenyne 3 is synthesized by the reaction of diboraazabutenyne 1 with aryl boron dibromide followed by the reduction. The ligand exchange to replace phosphine on the terminal sp2 B atom with carbene furnishes 4. 11B NMR, solid‐state structures, and computational studies disclose that 3 and 4 feature the extremely polarized B=B bond. 4 readily splits the N=N bond of both diazo compound and diazirine under ambient conditions, whereby one nitrogen atom is incorporated into the B=B moiety leading to a neutral diboraazaallene 6. The mechanism of the reaction between 4 and diazo compound is extensively investigated by density functional theory (DFT) calculations, as well as the isolation of an intermediate. [ABSTRACT FROM AUTHOR]

Allenes (>C=C=C<) are classified as cumulated dienes with a linear structure and an sp‐hybridized central carbon atom. We have synthesized and isolated a stable 2‐germapropadiene with bulky silyl substituents. The 2‐germapropadiene allene moiety adopts a linear structure both in the solid state and in solution. An X‐ray diffraction electron‐density‐distribution (EDD) analysis of this 2‐germapropadiene confirmed the linear C=Ge=C geometry with a formally sp‐hybridized germanium atom that bears two orthogonal C=Ge π‐bonds. Based on detailed structural and computational studies, we concluded that the linear geometry of the isolated 2‐germapropadiene most likely arises from the negative hyperconjugation of the silyl substituents at the terminal carbon atoms. The 2‐germapropadiene reacts rapidly with nucleophiles, indicating that the linearly oriented germanium atom is highly electrophilic. [ABSTRACT FROM AUTHOR]

Despite extensive efforts to develop high‐performance H2 evolution catalysts, this remains a major challenge. Here, we demonstrate the use of Cd/Pt precursor solutions for significant photocatalytic H2 production (154.7 mmol g−1 h−1), removing the need for a pre‐synthesized photocatalyst. In addition, we also report simultaneous in situ synthesis of Pt single‐atoms anchored CdS nanoparticles (PtSA‐CdSIS) during photoirradiation. The highly dispersed in situ incorporation of extensive Pt single atoms on CdSIS enables the enhancement of active sites and suppresses charge recombination, which results in exceptionally high solar‐to‐hydrogen conversion efficiency of ≈1 % and an apparent quantum yield of over 91 % (365 nm) for H2 production. Our work not only provides a promising strategy for maximising H2 production efficiency but also provides a green process for H2 production and the synthesis of highly photoactive PtSA‐CdSIS nanoparticles. [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]

Thermolysis of a 1 : 1 mixture of tris(di‐tert‐butylmethylsilyl)germane 9 and bis(di‐tert‐butylmethylsilyl)germane 17 at 100 °C produces unexpectedly octagermacubane 18, having two 3‐coordinate Ge0 atoms (40 % yield). 18 was characterized by X‐ray crystallography and it is a singlet biradical (according to DFT quantum mechanical calculations and the absence of an EPR signal). Reactions of 18 with CH2Cl2 and H2O yield the novel dichloro‐octagermacubane 24 and hydroxy‐octagermacubane 25, respectively. Reduction of 18 with tBuMe2SiNa in THF produces an isolable octagermacubane radical anion 26‐Na. Based on X‐ray crystallography, EPR spectroscopy and DFT quantum mechanical calculations, 26‐Na is classified as a Ge‐centered radical anion. [ABSTRACT FROM AUTHOR]

NiII 3,7,13,17‐tetrapyridyl‐5,15‐diazaporphyrin serves as a double tridentate ligand to PdII ions to provide a pincer‐type bispalladium complex. Electrochemical analysis revealed that the bispalladium complex shows excellent ability to accept electrons and reversible redox properties due to the coordination of the two cationic PdII centers to the meso‐nitrogen atoms. We isolated and characterized one‐ and two‐electron reduction species of the bispalladium complex. The 20π antiaromatic nature of the two‐electron reduction species was confirmed by 1H NMR spectroscopy, UV/Vis‐near‐IR (NIR) absorption spectra, and density functional theory (DFT) calculations. X‐ray diffraction revealed highly twisted structures for the bispalladium complexes regardless of the oxidation state. [ABSTRACT FROM AUTHOR]

Schnöckel's [(AlCp*)4] and Jutzi's [SiCp*][B(C6F5)4] (Cp*=C5Me5) are landmarks in modern main‐group chemistry with diverse applications in synthesis and catalysis. Despite the isoelectronic relationship between the AlCp* and the [SiCp*]+ fragments, their mutual reactivity is hitherto unknown. Here, we report on their reaction giving the complex salts [Cp*Si(AlCp*)3][WCA] ([WCA]−=[Al(ORF)4]− and [F{Al(ORF)3}2]−; RF=C(CF3)3). The tetrahedral [SiAl3]+ core not only represents a rare example of a low‐valent silicon‐doped aluminium‐cluster, but also—due to its facile accessibility and high stability—provides a convenient preparative entry towards low‐valent Si−Al clusters in general. For example, an elusive binuclear [Si2(AlCp*)5]2+ with extremely short Al−Si bonds and a high negative partial charge at the Si atoms was structurally characterised and its bonding situation analysed by DFT. Crystals of the isostructural [Ge2(AlCp*)5]2+ dication were also obtained and represent the first mixed Al−Ge cluster. [ABSTRACT FROM AUTHOR]

Cyclobutenones provide a straightforward four‐carbon ring platform for further structural elaborations in that every carbon atom of the ring could be potentially functionalized. We report here a nickel catalyzed enantioconvergent Negishi coupling of 4‐iodocyclobutenones with an array of aryl or alkenyl zinc reagents to access enantioenriched 4‐substituted cyclobutenones, from which a modular approach to the synthesis of 1,2,3,4‐tetrasubstituted cyclobutanes was demonstrated. [ABSTRACT FROM AUTHOR]

We report the enantioselective total syntheses of preussomerins EG1, EG2, and EG3. The key transformation is a stereospecific photochemical reaction involving 1,6‐hydrogen atom transfer to achieve retentive replacement of a C−H with a C−O bond, enabling otherwise‐difficult control of the spiroacetal stereogenic center. [ABSTRACT FROM AUTHOR]

Precise design and tuning of the micro‐atomic structure of single atom catalysts (SACs) can help efficiently adapt complex catalytic systems. Herein, we inventively found that when the active center of the main group element gallium (Ga) is downsized to the atomic level, whose characteristic has significant differences from conventional bulk and rigid Ga catalysts. The Ga SACs with a P, S atomic coordination environment display specific flow properties, showing CO products with FE of ≈92 % at −0.3 V vs. RHE in electrochemical CO2 reduction (CO2RR). Theoretical simulations demonstrate that the adaptive dynamic transition of Ga optimizes the adsorption energy of the *COOH intermediate and renews the active sites in time, leading to excellent CO2RR selectivity and stability. This liquid single atom catalysts system with dynamic interfaces lays the foundation for future exploration of synthesis and catalysis. [ABSTRACT FROM AUTHOR]

Transition‐metal mediated white phosphorus activation is of high interest as an ecological alternative to P4 chlorination pathway to the practically useful phosphorus products. Herein, we report a facile approach for P4 activation, transformation and subsequent functionalization using cobalt complexes bearing PNP ligands. The use of N,N‐bis(diphenylphosphino)amine as a ligand allows one to transform P4 tetrahedron into a zig‐zag chain with the formation of complex [Co(Ph2PNHP(Ph2)PPPPP(Ph2)NHPPh2)]BF4 (4). The presence of organic substituent at nitrogen atom in PNP ligand enables one to obtain complexes with η1‐coordinated P4 molecule, which indicates a crucial role of N−H bond in transformation of white phosphorus tetrahedron. Additionally, complex 4 can readily be functionalized by means of the reaction with Ph2PCl leading to the formation of a new complex bearing unique P9‐ligand. The obtained results provide opportunities for facile construction of new polyphosphorus ligands in the coordination sphere of transition metal complexes. [ABSTRACT FROM AUTHOR]

Fabricating single‐atom electrodes via atomic dispersion of active metal atoms into monolithic metal supports is of great significance to advancing the lab‐to‐fab translation of the electrochemical technologies. Here, we report an inherent oxide anchoring strategy to fasten ligand‐free isolated Ru atoms on the amorphous layer of monolithic Ti support by regulating the electronic metal‐support interactions. The prepared Ru single atom electrode exhibited exceptional electrochemical chlorine evolution activity, three orders of magnitude higher mass activity than that of commercial dimensionally stable anode, and also selectively reduced nitrate to ammonia with an unprecedented ammonia yield rate of 22.2 mol g−1 h−1 at −0.3 V. Furthermore, the Ru single atom monolithic electrode can be scaled up from 2×2 cm to 25×15 cm at least, thus demonstrating great potential for industrial electrocatalytic applications. [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]

Herein, we report a method that provides an array of benzocyclobutanol and benzocyclobutylamine derivatives with broad substrate scope and good functional group tolerance under mild reaction conditions. The reaction proceeds by engaging triplet biradical atom transfer of olefinic compounds in the activation of remote C(sp3)−H bonds upon visible‐light irradiation. The reaction mechanism involves the generation of triplet excited state of diarylethylene derivative and subsequent HAT process, and then the further ring‐closing reaction affording the product via an electrocyclization process. The plausible mechanism is supported by control and deuterium labeling experiments, kinetic analysis, and DFT calculations. [ABSTRACT FROM AUTHOR]

The development of a mild and general method for C(sp3)−H functionalization of cyclic amines has been an ongoing challenge. In this work, we describe the copper‐catalyzed enantioselective C(sp3)−H alkynylation of unactivated cyclic 2‐iodo‐benzamide under photo‐irradiation by intramolecular 1,5‐hydrogen atom transfer (HAT). The employment of a new bisoxazoline diphenylamine ligand, in conjunction with 1,1′‐bi‐2‐naphthol, which significantly improved the reduction potential of the copper complex, was the key to success of this chemistry. Mechanistic and computational studies supported that the new copper complex served the dual role as a photoredox and coupling catalyst, the reaction went through a radical process, and the intramolecular 1,5‐HAT process was involved in the rate‐limiting step. Apart from the broad substrate scope including unprecedented benzocyclic amines, this method also showed excellent diastereoselectivity in 2‐monosubstituted cyclic amines via substrate control. [ABSTRACT FROM AUTHOR]

It is an obstacle to precisely manipulate a doped heteroatom into a desired position in a metal nanocluster. Herein, we overcome this difficulty to obtain Pt1Au37(SCH2PhtBu)24 and Pt2Au36(SCH2PhtBu)24 nanoclusters via controllably doping Pt atoms into the kernels of Au38(SCH2PhtBu)24. We reveal that asymmetrical doping of one Pt atom into either of the cores of Au38(SCH2PhtBu)24 elevates the relative energy of the HOMO (highest occupied molecular orbital) accompanied by one valence electron loss of Pt1Au37(SCH2PhtBu)24, compared to Au38(SCH2PhtBu)24 with 14 electrons, while symmetrical doping of two Pt atoms into the cores of Au38(SCH2PhtBu)24 narrows the HOMO–LUMO gap (LUMO: lowest unoccupied molecular orbital) of Pt2Au36(SCH2PhtBu)24 with two valence electrons less. Consequently, Pt1Au37(SCH2PhtBu)24 shows an electron‐spin‐induced high activity for CO2 electroreduction, whereas Pt2Au36(SCH2PhtBu)24 is least efficient and Au38(SCH2PhtBu)24 has a decent performance. [ABSTRACT FROM AUTHOR]

Herein, we report a polar‐radical relay strategy for α‐C−H amination of cyclic amines with N‐chloro‐N‐sodio‐carbamates. The relay is initiated by in situ generation of cyclic iminium intermediate using N‐iodosuccinimide (NIS) oxidant as an initiator, which then operates through a series of polar (addition and elimination) and radical (homolysis, hydrogen‐ and halogen atom transfer) reactions to enable the challenging C−N bond formation in a controlled manner. A broad range of α‐amino cyclic amines were readily accessed with excellent regioselectivity, and the superb applicability was further demonstrated by functionalization of biologically relevant compounds. [ABSTRACT FROM AUTHOR]

Buckybowls have unique properties that can be tailored by embedding main‐group elements into their π‐scaffolds. Herein, a synthetic approach is developed for producing monoazadichalcogenasumanenes (4 a/4 b, 6 a/6 b, 7 a/7 b) derived from sumanene by replacing its three benzylic carbons with one nitrogen and two chalcogen atoms (S for 4 a/4 b, Se for 6 a/6 b, Te for 7 a/7 b). Monoazadichalcogenasumanenes are deeper π‐bowls than trichalcogensumanenes as the C−N bond is much shorter than C−X (X=S, Se, Te). The bowl‐depth of 4 b (0.95 Å) is greater than that of corannulene (0.85 Å). The nitrogen atom donates electron density to the entire π‐system that makes monoazadichalcogenasumanenes electron‐rich. They undergo ring reconstruction of chalcogenophene ring via transferring a chalcogen atom from one molecule to another under acidic conditions. The nitrogen and chalcogen atoms play crucial role on this reaction. [ABSTRACT FROM AUTHOR]

Herein, we report a novel method for the synthesis of metallabenzenes by swapping the phosphorus atom in an aromatic phosphinine ring with transition metal fragments. The oxidation of a phosphine‐phosphinine‐phosphine pincer iridium complex by O2 triggered the replacement of the phosphorus atom of the phosphinine ring by an iridium fragment to afford iridabenzene. Dianionic rhodabenzene was also synthesized from a phosphinine rhodium complex by oxidation of the phosphorus atom, followed by subsequent reduction using metallic potassium. The aromaticity of the newly synthesized irida‐ and rhoda‐benzenes was evaluated both experimentally and theoretically. [ABSTRACT FROM AUTHOR]

The rational design of single‐atom catalysts featuring excellent conductivity, highly accessible discrete active sites and favorable mass transfer is crucial for electrocatalysis but remains challenging. In this study, a reliable Ni‐catalyzed and Ni‐templated strategy is developed to synthesize a single‐atom catalyst by transforming metallic Ni into single‐Ni atoms anchored on hollow porous urchin‐like (HPU) N‐doped carbon (NC) (designated as Ni‐NC(HPU)), which possesses high crystallinity and sufficient Ni‐N4 moiety (2.4 wt %). The unique hollow thorns on the surface, good conductivity and large external surface area facilitate electron/mass transfer and exposure of single‐Ni sites. As a result, the Ni‐NC(HPU) catalyst exhibits remarkable activity and high stability for CO2 electroreduction. Moreover, this synthetic strategy can also be facilely extended to prepare distinct hollow porous architectures with similar components, such as the wire‐ and sphere‐like ones. [ABSTRACT FROM AUTHOR]

Controlling the location of aluminum atoms in a zeolite framework is critical for understanding structure–performance relationships of catalytic reaction systems and tailoring catalyst design. Herein, we report a strategy to preferentially relocate mordenite (MOR) framework Al atoms into the desired T3 sites by low‐pressure SiCl4 treatment (LPST). High‐field 27Al NMR was used to identify the exact location of framework Al for the MOR samples. The results indicate that 73 % of the framework Al atoms were at the T3 sites after LPST under optimal conditions, which leads to controllably generating and intensifying active sites in MOR zeolite for the dimethyl ether (DME) carbonylation reaction with higher methyl acetate (MA) selectivity and much longer lifetime (25 times). Further research reveals that the Al relocation mechanism involves simultaneous extraction, migration, and reinsertion of Al atoms from and into the parent MOR framework. This unique method is potentially applicable to other zeolites to control Al location. [ABSTRACT FROM AUTHOR]

We report the structures, stability and catalysis properties of two Ag21 nanoclusters, namely [Ag21(H2BTCA)3(O2PPh2)6]SbF6 (1) and [Ag21(C≡CC6H3‐3,5‐R2)6(O2PPh2)10]SbF6 (2) (H4BTCA=p‐tert‐butylthiacalix[4]arene, R=OMe). Both Ag21 structures possess an identical icosahedral kernel that is surrounded by eight peripheral Ag atoms. Single‐crystal structural analysis and ESI‐MS revealed that 1 is an 8‐electron cluster and 2 has four free electrons. Theoretical results show that the P‐symmetry orbitals are found as HOMO‐1 and HOMO states in 1, and the frontier unoccupied molecular orbitals (LUMO, LUMO+1 and LUMO+2) show D‐character, indicating 1 is a superatomic cluster with an electronically closed shell 1S21P6, while 2 has an incomplete shell configuration 1S21P2. These two Ag21 clusters show superior stability under ambient conditions, and 1 is robust even at 90 °C in toluene and under oxidative conditions (30 % H2O2). Significantly, 2 exhibits much higher activity than 1 as catalyst in the reduction of 4‐nitrophenol. This work demonstrates that ligands can influence the electronic structures of silver clusters, and further affect their stability and catalytic performance. [ABSTRACT FROM AUTHOR]

The development of highly active and stable bifunctional noble‐metal‐based electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) is a crucial goal for clean and renewable energy, which still remains challenging. Herein, we report an efficient and stable catalyst comprising a Co single atom incorporated in an RuO2 sphere for HER and OER, in which the Co single atom in the RuO2 sphere was confirmed by XAS, AC‐STEM, and DFT. This tailoring strategy uses a Co single atom to modify the electronic structures of the surrounding Ru atoms and thereby remarkably elevates the electrocatalytic activities. The catalyst requires ultralow overpotentials, 45 mV for HER and 200 mV for OER, to deliver a current density of 10 mA cm−2. The theoretical calculations reveal that the energy barriers for HER and OER are lowered after incorporation of a cobalt single atom. [ABSTRACT FROM AUTHOR]

Cyclopentenes and indenes are important structural scaffolds in synthetic, medical, and material chemistry. Cyclization of alkynes via remote C−H functionalization is an appealing approach to construct these motifs due to its high efficiency and step‐economy. Herein, a traceless directing group strategy was designed to reverse the regioselectivity of radical addition which enabled an unprecedented photocatalytic sulfonylcarbocyclization of terminal alkynes by forming C−C bond on inert C(sp3)−H bond. It offers a facile access to decorated cyclopentenes and indenes under mild conditions. The resultant products could be converted into a set of valuable molecular scaffolds, including a key intermediate of AM‐6226. Mechanistic experiments suggest a radical cascade pathway comprising a Markovnikov‐type sulfonylation, 1,5‐hydrogen atom transfer, 5‐endo‐trig cyclization, and β‐elimination. This study lays further groundwork for the use of anti‐Baldwin 5‐endo‐trig radical cyclization in rapidly assembling five‐membered carbocycles. [ABSTRACT FROM AUTHOR]

A series of acyclic anion receptors containing chalcogen bond (ChB) and halogen bond (XB) donors integrated into a neutral 3,5‐bis‐triazole pyridine scaffold are described, in which systematic variation of the electronic‐withdrawing nature of the aryl substituents reveal a dramatic modulation in sigma‐hole donor atom potency for anion recognition. Incorporation of strongly electron‐withdrawing perfluorophenyl units appended to the triazole heterocycle telluro‐ or iodo‐ donor atoms, or directly linked to the tellurium donor atom dramatically enhances the anion binding potency of the sigma‐hole receptors, most notably for the ChB and XB receptors displaying over thirty‐fold and eight‐fold increase in chloride anion affinity, respectively, relative to unfluorinated analogues. Linear free energy relationships for a series of ChB based receptors reveal the halide anion recognition behaviour of the tellurium donor is highly sensitive to local electronic environments. This is especially the case for those directly appended to the Te centre (3⋅ChB), where a remarkable enhancement of strength of binding and selectivity for the lighter halides is observed as the electron‐withdrawing ability of the Te‐bonded aryl group increases, highlighting the exciting opportunity to fine‐tune anion affinity and selectivity in ChB‐based receptor systems. [ABSTRACT FROM AUTHOR]

A considerable amount of platinum (Pt) is required to ensure an adequate rate for the oxygen reduction reaction (ORR) in fuel cells and metal‐air batteries. Thus, the implementation of atomic Pt catalysts holds promise for minimizing the Pt content. In this contribution, atomic Pt sites with nitrogen (N) and phosphorus (P) co‐coordination on a carbon matrix (PtNPC) are conceptually predicted and experimentally developed to alter the d‐band center of Pt, thereby promoting the intrinsic ORR activity. PtNPC with a record‐low Pt content (≈0.026 wt %) consequently shows a benchmark‐comparable activity for ORR with an onset of 1.0 VRHE and half‐wave potential of 0.85 VRHE. It also features a high stability in 15 000‐cycle tests and a superior turnover frequency of 6.80 s−1 at 0.9 VRHE. Damjanovic kinetics analysis reveals a tuned ORR kinetics of PtNPC from a mixed 2/4‐electron to a predominately 4‐electron route. It is discovered that coordinated P species significantly shifts d‐band center of Pt atoms, accounting for the exceptional performance of PtNPC. [ABSTRACT FROM AUTHOR]

The asymmetric synthesis of enantiopure pyrrolidines is reported via a streamlined strategy relying on two sequential C−H functionalizations of simple hydrocarbons. The first step is a regio‐ and stereoselective catalytic nitrene C−H insertion. Then, a subsequent diastereoselective cyclization involving a 1,5‐hydrogen atom transfer (HAT) from a N‐centered radical leads to the formation of pyrrolidines that can then be converted to their free NH‐derivatives. [ABSTRACT FROM AUTHOR]

Disilenes with differently coordinated silicon atoms are not known. Here, we have shown the high yield synthesis of a range of disilenes (2–4 and 6) upon reaction of a hypersilyl silylene PhC(NtBu)2SiSi(SiMe3)3 (1) with aliphatic chlorophosphines. The most striking characteristic of these disilenes is the presence of two differently coordinated Si atoms (one is three‐coordinated, the other four‐coordinated). The analogous reaction with Ph2PCl did not afford the desired disilene, but, surprisingly, led to the first tetraphosphinosilane (8). DFT calculations were performed to understand the bonding in disilenes and differences in reactivity of the complexes. [ABSTRACT FROM AUTHOR]

In the electrochemical CO2 reduction reaction (CO2RR), it is challenging to develop a stable, well‐defined catalyst model system that is able to examine the influence of the synergistic effect between adjacent catalytic active sites on the selective generation of C1 or C2 products. We have designed and synthesized a stable crystalline single‐chain catalyst model system for electrochemical CO2RR, which involves four homomorphic one‐dimensional chain‐like compounds (Cu‐PzH, Cu‐PzCl, Cu‐PzBr, and Cu‐PzI). The main structural difference of these four chains is the substituents of halogen atoms with different electronegativity on the Pz ligands. Consequently, different synergistic effects between bi‐copper centers lead to changes in the faradic efficiency (FECH4 :FEC2H4). This work provides a simple and stable crystalline single‐chain model system for systematically studying the influence of coordination microenvironment on catalytically active centers in the CO2RR. [ABSTRACT FROM AUTHOR]

Photodriven nonoxidative coupling of CH4 (NOCM) is an attractive potential way to use abundant methane resources. Herein, an n‐type doped photocatalyst for NOCM is created by doping single‐atom Nb into hierarchical porous TiO2–SiO2 (TS) microarray, which exhibits a high conversion rate of 3.57 μmol g−1 h−1 with good recyclability. The Nb dopant replaces the 6‐coordinated titanium on the (1 0 1) plane and forms shallow electron‐trapped surface polarons along [0 1 0] direction and the comparison of different models proves that the electron localization caused by the n‐type doping is beneficial to both methane activation and ethane desorption. The positive effect of n‐type dopant on CH4 conversion is further verified on Mo‐, W‐ and Ta‐doped composites. In contrast, the doping of p‐type dopant (Ga, Cu, Fe) shows a less active influence. [ABSTRACT FROM AUTHOR]

Keywords: Au46(m-MBT)26; Au48(m-MBT)26; gold nanoclusters; photoluminescence; traceless removal EN Au46(m-MBT)26 Au48(m-MBT)26 gold nanoclusters photoluminescence traceless removal 1 1 1 04/03/21 20210412 NES 210412 B Nanocluster b Die Synthese und Charakterisierung von zwei neuen Gold-Nanoclustern wird in der Zuschrift auf S. 8750 von Nan Xia, Zhikun Wu et al. vorgestellt. Au46(m-MBT)26, Au48(m-MBT)26, gold nanoclusters, photoluminescence, traceless removal. [Extracted from the article]

Carbyne is a one‐dimensional allotrope of carbon consisting of a linear chain of carbon atoms bonded to each other with exceptional strength. Its outstanding mechanical, optical, and electronic properties have been theoretically predicted, but its stability has only been achieved when grown encapsulated in the hollow core of carbon nanotubes. One of the advantages of this confinement is that its properties can be controlled by the chain's length and surrounding environment. We investigated an alternative way of gaining control of its properties is using isotope labelling as tuning mechanism. The optimized liquid precursor was first chosen among several options, which can greatly enhance the yield of the confined carbyne. Then isotopic labelled liquid precursor was encapsulated for further synthesis of isotopic labelled confined carbyne. This allowed us to obtain pioneering results on isotope engineered carbyne with around 11.9 % of 13C‐labelling using 13C‐methanol as precursor. [ABSTRACT FROM AUTHOR]

Converting CO2 and H2O into carbon‐based fuel by IR light is a tough task. Herein, compared with other single‐component photocatalysts, the most efficient IR‐light‐driven CO2 reduction is achieved by an element‐doped ultrathin metallic photocatalyst‐Ni‐doped CoS2 nanosheets (Ni‐CoS2). The evolution rate of CH4 over Ni‐CoS2 is up to 101.8 μmol g−1 h−1. The metallic and ultrathin nature endow Ni‐CoS2 with excellent IR light absorption ability. The PL spectra and Arrhenius plots indicate that Ni atoms could facilitate the separation of photogenerated carriers and the decrease of the activation energy. Moreover, in situ FTIR, DFT calculations, and CH4‐TPD reveal that the doped Ni atoms in CoS2 could effectively depress the formation energy of the *COOH, *CHO and desorption energy of CH4. This work manifests that element doping in atomic level is a powerful way to control the reaction intermediates, providing possibilities to realize high‐efficiency IR‐light‐driven CO2 reduction. [ABSTRACT FROM AUTHOR]

Removing or adding kernel atoms of metal nanoclusters (NCs) without leaving a trace is a substantial challenge because the kernel atoms are inside and covered by the outer staples. However, such kernel tuning is very important for improving the properties and acquiring an in‐depth understanding of the kernel‐property correlation. Photoluminescence (PL) is one of the most intriguing characteristics of metal NCs but has not been well understood until now. Inspired by these challenges/questions, we conducted this study and, for the first time, achieved the traceless removal of two kernel atoms in a gold nanocluster by applying a simple thermal treatment and revealed its impact on PL. Further, we demonstrated that the kernel Au‐Au bond length can be an indicator for a comparison of the PL or kernel charge state between nanoclusters with similar kernel structures and sizes. [ABSTRACT FROM AUTHOR]

A new mode of carbene‐catalyzed heteroatom activation and asymmetric reactions is disclosed. The reaction starts with addition of a carbene catalyst to a (benz)imidazole‐derived aldimine substrate. Subsequent oxidation and proton transfer lead to the formation of a catalyst‐bound triaza‐diene as the key intermediate, in which the nitrogen atom at a site remote to the catalyst‐substrate bond is activated. This unusual triaza‐diene intermediate then undergoes highly enantioselective reactions with activated ketones through a concerted asynchronous pathway, as supported by mechanistic studies and preliminary density function theory calculation. [ABSTRACT FROM AUTHOR]

Herein we report the synthesis, structure solution, and catalytic properties of PST‐31, which has an unprecedented framework topology. This high‐silica (Si/Al=16) zeolite was synthesized using a pyrazolium‐based dication with a tetramethylene linker as an organic structure‐directing agent (OSDA) in hydroxide media. The PST‐31 structure is built from new building layers containing four‐, five‐, six‐, and seven‐membered rings, which are connected by single four‐membered rings in the interlayer region to form a two‐dimensional pore system. Its channels consist of [4.56.6.9.11] and [5.6.7.9.10.11] cavities and are thus delimited by nine‐, ten‐, and eleven‐membered rings. The OSDA cations in as‐synthesized PST‐31 were determined to reside without disorder in the large [42.514.64.72.94] cavities composed of smaller [4.56.6.9.11] and [5.6.7.9.10.11] ones, leading to a symmetry coincidence between the OSDA and the surrounding zeolite cavity. The proton form of PST‐31 was found to be selective for the cracking of n‐hexane to light olefins. [ABSTRACT FROM AUTHOR]

The N‐heterocyclic silylene (NHSi) [Ph2P(tBuN)2]SiCl (1), supported by an iminophosphonamide ligand, was obtained from the dehydrochlorination of [Ph2P(tBuN)2]SiHCl2 (2) with LiN(SiMe3)2. NHSi 1 contains an extremely high‐energy HOMO level and consequently displays unique coordination behavior toward RhI complexes. When 1 was treated with 1/4 of an equivalent of [RhCl(cod)]2 (cod=1,5‐cyclooctadiene), the 14‐electron Y‐shaped bis(chlorosilylene) RhI complex 5 was obtained as dark purple crystals. The reaction of 1 with 1/6 of an equivalent of [RhCl(cod)]2 yielded the cationic tris(silylene)‐RhI complex [6]+⋅Cl− as red crystals, wherein a two‐coordinated silylene ligand engages in a Si=Rh double bond. A structural analysis of 5 and [6]+⋅Cl− revealed that the central rhodium atoms adopt trigonal and square‐planar coordination geometries, respectively, with considerably shortened Si‐Rh bonds [5: 2.1605(5) Å; [6]+: 2.133(1) Å]. [ABSTRACT FROM AUTHOR]

Efforts have been devoted to achieving a highly efficient artificial synthesis of ammonia (NH3). Reported herein is a novel Fe‐MoS2 catalyst with Fe atomically dispersed onto MoS2 nanosheets, imitating natural nitrogenase, to boost N2 electroreduction into NH3 at room temperature. The Fe‐MoS2 nanosheets exhibited a faradic efficiency of 18.8 % with a yield rate of 8.63 μgNH3 mgcat.−1 h−1 for NH3 at −0.3 V versus the reversible hydrogen electrode. The mechanism study revealed that the electroreduction of N2 was promoted and the competing hydrogen evolution reaction was suppressed by decorating the edge sites of S in MoS2 with the atomically dispersed Fe, resulting in high catalytic performance for the electroreduction of N2 into NH3. This work provides new ideas for the design of catalysts for N2 electroreduction and strengthens the understanding about N2 activation over Mo‐based catalysts. [ABSTRACT FROM AUTHOR]

The 1,4‐palladium shift strategy allows the functionalization of remote C−H bonds that are difficult to reach directly. Reported here is a domino reaction proceeding by C(sp3)−H activation, 1,4‐palladium shift, and amino‐ or alkoxycarbonylation, which generates a variety of amides and esters bearing a quaternary β‐carbon atom. Mechanistic studies showed that the aminocarbonylation of the σ‐alkylpalladium intermediate arising from the palladium shift is fast using PPh3 as the ligand, and leads to the amide rather than the previously reported indanone product. [ABSTRACT FROM AUTHOR]

By integration of iminyl radical‐triggered 1,5‐hydrogen atom transfer and (5+2) or (5+1) annulation processes, a series of structurally novel and interesting azepine and spiro‐tetrahydropyridine derivatives have been successfully prepared in moderate to good yields. This method utilizes FeCl2 as the catalyst and readily available oximes as five‐atom units, while showcasing broad substrate scope and good functional group compatibility. The annulation products can be easily converted into many valuable compounds. Moreover, DFT calculation studies are performed to provide some insights into the possible reaction mechanisms for the (5+2) and (5+1) annulations. [ABSTRACT FROM AUTHOR]

Closing the anthropogenic carbon cycle by converting CO2 into reusable chemicals is an attractive solution to mitigate rising concentrations of CO2 in the atmosphere. Herein, we prepared Ni metal catalysts ranging in size from single atoms to over 100 nm and distributed them across N‐doped carbon substrates which were obtained from converted zeolitic imidazolate frameworks (ZIF). The results show variance in CO2 reduction performance with variance in Ni metal size. Ni single atoms demonstrate a superior Faradaic efficiency (FE) for CO selectivity (ca. 97 % at −0.8 V vs. RHE), while results for 4.1 nm Ni nanoparticles are slightly lower (ca. 93 %). Further increase the Ni particle size to 37.2 nm allows the H2 evolution reaction (HER) to compete with the CO2 reduction reaction (CO2RR). The FE towards CO production decreases to under 30 % and HER efficiency increase to over 70 %. These results show a size‐dependent CO2 reduction for various sizes of Ni metal catalysts. [ABSTRACT FROM AUTHOR]

The Zintl anion (Ge2As2)2− represents an isostructural and isoelectronic binary counterpart of yellow arsenic, yet without being studied with the same intensity so far. Upon introducing [(PPh3)AuMe] into the 1,2‐diaminoethane (en) solution of (Ge2As2)2−, the heterometallic cluster anion [Au6(Ge3As)(Ge2As2)3]3− is obtained as its salt [K(crypt‐222)]3[Au6(Ge3As)(Ge2As2)3]⋅en⋅2 tol (1). The anion represents a rare example of a superpolyhedral Zintl cluster, and it comprises the largest number of Au atoms relative to main group (semi)metal atoms in such clusters. The overall supertetrahedral structure is based on a (non‐bonding) octahedron of six Au atoms that is face‐capped by four (GexAs4−x)x− (x=2, 3) units. The Au atoms bind to four main group atoms in a rectangular manner, and this way hold the four units together to form this unprecedented architecture. The presence of one (Ge3As)3− unit besides three (Ge2As2)2− units as a consequence of an exchange reaction in solution was verified by detailed quantum chemical (DFT) calculations, which ruled out all other compositions besides [Au6(Ge3As)(Ge2As2)3]3−. Reactions of the heavier homologues (Tt2Pn2)2− (Tt=Sn, Pb; Pn=Sb, Bi) did not yield clusters corresponding to that in 1, but dimers of ternary nine‐vertex clusters, {[AuTt5Pn3]2}4− (in 2–4; Tt/Pn=Sn/Sb, Sn/Bi, Pb/Sb), since the underlying pseudo‐tetrahedral units comprising heavier atoms do not tend to undergo the said exchange reactions as readily as (Ge2As2)2−, according to the DFT calculations. [ABSTRACT FROM AUTHOR]

3‐Point annulations, or phenalenannulations, transform a benzene ring directly into a substituted pyrene by "wrapping" two new cycles around the perimeter of the central ring at three consecutive carbon atoms. This efficient, modular, and general method for π‐extension opens access to non‐symmetric pyrenes and their expanded analogues. Potentially, this approach can convert any aromatic ring bearing a ‐CH2Br or a ‐CHO group into a pyrene moiety. Depending upon the workup choices, the process can be directed towards either tin‐ or iodo‐substituted product formation, giving complementary choices for further various cross‐coupling reactions. The two‐directional bis‐double annulation adds two new polyaromatic extensions with a total of six new aromatic rings at a central core. [ABSTRACT FROM AUTHOR]