Dibenzo[ b, f][1, 5]diazocines are a class of eight-membered heterocycles, which exhibit unique rigid saddle-shaped structure and possess inherent chirality. In this study, we report a convenient and straightforward method for the catalytic enantioselective synthesis of these unique chiral molecules through chiral phosphoric acid-catalyzed dimerization of 2-acylbenzoisocyanates. Notably, the addition of corresponding 2-acylaniline as the co-catalyst significantly improved the efficiency of these reactions, and a simple phase separation operation resulted in products with excellent enantiopurity. Experimental studies were performed to elucidate the mechanism behind these reactions, leading to the proposal of a plausible reaction mechanism based on the study findings.

Covalent organic frameworks (COFs) driven photocatalytic organic transformations especially photooxidation reactions have become a fertile topic and attracted numerous research attentions. Boosting the charge generation and transport process is the key factor for achieving high catalytic efficiencies. As one of the most effective strategies, the introduction of “heavy atoms” into the long-range ordered conjugated backbones can effectively facilitate the intersystem crossing (ISC) process and hence improve the generation of active oxygens, which is beneficial for the oxidation. In this work, we designed and synthesized a benzoselenadiazole based covalent organic framework (COF) material,   BSe-COF with heavy atom of selenium (Se), and a benzothiadiazole based  BT-COF with isomorphic backbone for comparison. Compared to  BT-COF,   BSe-COF exhibits broader absorption range, stronger photocurrent response and enhanced intersystem crossing (ISC) with higher singlet oxygen ( ¹O ₂) generation efficiency. When applied in photocatalytic organic transformation,   BSe-COF presents remarkably higher photocatalytic activity in the oxidation of sulfides than  BT-COF under the irradiation of blue LED lamp. Furthermore,   BSe-COF can be used as efficient photocatalyst for the window ledge reaction with high yields (over 84%) of various sulfoxides from a wide range of thioether substrates scope.

Bond dissociation energy (BDE), which refers to the enthalpy change for the homolysis of a specific covalent bond, is one of the basic thermodynamic properties of molecules. It is very important for understanding chemical reactivities, chemical properties and chemical transformations. Here, a machine learning-based comprehensive BDE prediction model was established based on the  iBonD experimental BDE dataset and the calculated BDE dataset by St. John  et al. Differential Structural and PhysicOChemical (D-SPOC) descriptors that reflected changes in molecules’ structural and physicochemical features in the process of bond homolysis were designed as input features. The model trained with LightGBM algorithm gave a low mean absolute error (MAE) of 1.03 kcal/mol on the test set. The D-SPOC model could apply to accurate BDE prediction of phenol O—H bonds, uncommon N-SCF ₃ and O-SCF ₃ reagents, and  β-C—H bonds in enamine intermediates. A fast online prediction platform was constructed based on the D-SPOC model, which could be found at  http://isyn.luoszgroup.com/bde_prediction.

Catechol-formaldehyde resin (CFR) is very attractive for H ₂O ₂ production via the catalytic process. However, the H ₂O ₂ formation is accompanied by the oxidation of catechol groups to  o-benzoquinone groups on CFR, which will cause irreversible damage to CFR and greatly limit its long-term stable catalytic activity. Herein, CdS/CFR composite photocatalyst with a core-shell structure was synthesized by hydrothermal method. The photogenerated electrons of CdS are used as a powerful driving force for the reversible redox conversion between catechol groups and  o-benzoquinone groups on the CFR, which not only achieves the long-term stability of CFR-catalyzed production of H ₂O ₂, but also promotes the separation efficiency of photogenerated e ^- and h ⁺ in CdS, greatly inhibiting their recombination, so as to maintain CdS stability. The H ₂O ₂ yield of CdS/CFR can accumulate to 1.65 mmol·L ^-1 under visible light for 6 h without sacrificial agent, which is about 3.1 and 2 times that of CdS and CFR, respectively, and CdS/CFR can persist for 10 cycles of photocatalysis (60 h). CdS/CFR also improves the yield of photocatalytic H ₂O ₂ by increasing the selectivity of H ₂O ₂ and inhibiting its decomposition. This work offers a novel tactic for expanding the application of CFR in photocatalytic generation of H ₂O ₂.

The rhodium-catalyzed C—H bond activation and cyclization of 3-oxopent-4-enenitriles with alkynes proceed efficiently. Various 2 H-pyrans with multiple substituents are achieved in good yields through regioselective formation of C—O and C—C bonds. Transformations involving hydroxy-alkynoates resulted in products with a furo[3, 4- b]pyran skeleton via further intramolecular ester exchange processes. Different from the traditional “1-oxatrienes pathway”, this method for the synthesis of useful 2 H-pyrans possesses certain highlights in terms of readily available substrates, stable and easily derivatized products, gentle and convenient operation process, and step and atom economy.

The stereochemical synthesis of highly substituted Danishefsky-type dienes remains unsolved in organic chemistry. We describe a simple and efficient approach for the stereoselective synthesis of Danishefsky-type trisubstituted dienes from readily available propargylic esters via Pd-catalyzed dienylation reaction through the key intermediate metallacyclobutene in a regio-, chemo- and stereoselective fashion. This method facilitates a broad range of challenging trisubstituted dienes with a high level of stereocontrol. The synthetic utilities of oxygenated trisubstituted dienes have been demonstrated by the downstream chemistry, which notably undergoes Diels-Alder reaction with a variety of electron-deficient dienophiles to furnish multisubstituted cyclohexenes in good yields with excellent stereoselectivity.

We report herein the first observation of MOF nanozyme enabling dual-functional photo-induced charge transfer and biomimetic precipitation for advanced organic photoelectrochemical transistor (OPECT) bioanalysis. Specifically, Fe/Co-MIL-88, serving simultaneously as the semiconductor and nanozyme, was explored as a dual-functional gating module in OPECT. Upon light illumination, it could accelerate the charge transfer of the photogate to produce enhanced photo-induced voltage. Meanwhile, its catalytic property could efficiently produce biomimetic precipitation to block the nanopores in Fe/Co-MIL-88 and thus alter the device characteristics. The generic bioanalytical potential of such a rationale was then demonstrated with an aptasensing assisted by magnetic separation. This work represents the first exploration of biomimetic precipitation from MOF nanozymes for generic OPECT bioanalysis, it is expected to attract more interest in various nanozymes for novel optoelectronic bioanalytics.

Chiral BINAM-derived selenide/achiral acid co-catalyzed atroposelective electrophilic sulfenylation of pyrrole derivatives has been realized for the first time. A variety of C—N axially chiral sulfur-containing pyrrole derivatives were readily obtained in moderate to good yields with moderate to excellent enantioselectivities. This catalytic system involves sequential desymmetrization and kinetic resolution.

We detail the generation of a pulsed atomic oxygen (AO) broad beam with a high flux-density via collision-induced dissociation of O ₂ to support practical industrial exploitation of AOs, particularly for facilitating 2-dimenstional oxidation/etching at a fast rate of one-monolayer per second in an area ≥ 1000 cm ². This innovation fuses the following interdisciplinary concepts: (a) a high density of O ⁺ can be produced in an electron-cyclotron-resonance (ECR) O ₂ plasma; (b) O ⁺ can be extracted and accelerated with an aperture-electrode in the plasma; (c) O ⁺ with adequate kinetic energy can initiate a cascade of gas-phase collisions in the presence of O ₂; (d) collision-induced dissociation of O ₂ yields AOs with adequate kinetic energy which can cause additional collision-induced dissociation of O ₂. Computational simulations of such collisions, with both  ab initio molecular dynamics and direct simulation Monte Carlo methods, are used to guide the experimental generation of the proposed AO-beam. We experimentally demonstrate the highest known AO mean flux-density of about 1.5 × 10 ¹⁶ atoms·cm ^-2·s ^-1 in a broad-beam, and use it to oxidatively modify a self-assembled molecular layer of siloxane on a silicon wafer. In addition, we also demonstrate the growth of Al ₂O ₃ through an AO-assisted atomic layer deposition process at room temperature.

The development of catalytic asymmetric methods that enable access to value-added functionalities or structures, exemplified by allylic alcohols, is a highly interesting yet challenging topic from both academic and industrial perspectives. However, before recent advances in chemical catalysis, there were scarce protocols toward constructing enantioenriched tertiary allylic alcohol scaffolds. In this context, peptide-mimic phosphonium salts were found to be highly efficient in catalytic asymmetric α-hydroxylation of α, β-unsaturated and/or β, γ-unsaturated compounds with satisfactory regio- and stereochemical outcomes (up to 97% yield and 95% ee). This methodology tolerates a broad array of substrates and thus provides an expeditious and unified platform for the assembly of enantioenriched tertiary allylic alcohols by avoiding the use of additional reductants and expensive metal catalysts. Furthermore, the power of this protocol is enlarged by simple conditions and the use of air as a source of hydroxyl functionality.

A general and broadly applicable copper and photoredox dual-catalyzed multicomponent 1, 4-perfluoroalkylcyanation of 1, 3-enynes has been developed. This protocol enjoys success with high regioselectivity, mild reaction conditions, and excellent functional-group tolerance, allowing the facile synthesis of structurally diverse perfluoroalkylated allenes from readily available fluoroalkyl halides, 1, 3-enynes and TMSCN in a one-pot manner. A reasonable mechanism has been proposed according to a series of control experiments.

A [2 + 1 + 1 + 1] cyclization reaction has been developed for the synthesis of multisubstituted  β-pyrrolidinones from commercially available aryl methyl ketones, primary amines, and ethyl nitroacetate. In this I ₂–DMSO-meditated process, the C—NO ₂ bond of ethyl nitroacetate is cleaved, affording a C1 synthon, and the formation of two C—C and two C—N bonds and a quaternary carbon center are constructed in one pot. This method has good substrate compatibility and permits the late-stage modification of pharmaceutical compounds.

Copolymerization as an efficient strategy can provide an opportunity to create new closed-loop recyclable polymeric materials with tailored properties that are generally inaccessible to the individual homopolymers. In this contribution, the bulk ring-opening copolymerization of bio-renewable δ-caprolactone and  trans-hexahydro-(4, 5)-benzofuranone was achieved to produce closed-loop recyclable copolyesters by using an organobase/urea binary catalyst at room temperature. The obtained copolyesters exhibited composition-dependent thermal properties. Remarkably, the obtained copolyesters were able to depolymerize back to recover the corresponding monomers under mild conditions. The copolyesters with suitable compositions can be directly used as pressure-sensitive adhesives (PSAs) that possessed comparable peel strength with the commercially available PSA scotch tapes. When the copolyesters were mixed with plasticizers, the as-prepared PSAs exhibited desirable adhesive failure and can be used as removable post-it note.

Compounds with magnetic bistability is highly attractive for the construction of switches, thermal sensors, information-storage media and memory devices. Herein, we report a crystalline fullerene radical anion salt [Na(THF) ₅]C ₆₀ ( 1), obtained by the reduction of C ₆₀ with Na in solution, which exhibits magnetic bistability accompanied with one magnetostructural transition, giving low temperature (LT), high temperature (HT) phases and a metastable phase. Fullerene radical anions (C ₆₀ ^•-) in the structure were found arranged into a three-dimensional close-packed honeycomb subnetwork with hollow channels occupied by complex cations [Na(THF) ₅] ⁺ as spacers. The magnetic bistability is attributed to structural transitions as the LT−IT phase transition was associated with the orientational disorder of fullerene anions and the distortion of the complex cations [Na(THF) ₅] ⁺ in the 3D packing of fullerene anions.

An electrocatalytic multicomponent cascade cross-coupling for the synthesis of chalcogenosulfonates has been established. This approach does not require the use of transition metals, acids, and external oxidants. The gentle conditions and tolerance to a wide variety of functional groups permit the derivatization of complex indoles.

Chemical prelithiation is widely proven to be an effective strategy to address the low initial coulombic efficiency (ICE) of promising SiO x anode. Though the reagent composition has been widely explored, the Li ⁺ solvation structure, which practically plays the cornerstone role in the prelithiation ability, rate, uniformility, has rarely been explored. A novel environmentally-friendly reagent with weak solvent cyclopentyl methyl ether (CPME) is proposed that enables both improved ICE and spatial homogeneous solid electrolyte interphase (SEI). And the prelithiation behavior and mechanism were explored focused on the Li ⁺ solvation structure. Both theoretical investigation and spectroscopic results suggest that weak solvent feature of CPME reduces the solvent coordination number and decreases the Li ⁺ desolvation energy. The optimized Li ⁺ solvation structure enables high-efficiency prelithiation that ensures the horizontal homogenization and mechanical properties of SEI. Moreover, the accompanied CPME molecules preferentially occupy positions in initial SEI, reducing the likelihood of LiPF ₆ decomposition and promoting longitudinal homogenization of SEI. Consequently, the efficient and homogenous prelithiation enables impressive ICE of 109.52% and improved cycling performance with 80.77% retained after 300 cycles via just 5 min soaking. Furthermore, the full cells with LiNi _0.83Co _0.12Mn _0.05O ₂ (NCM831205) cathode display an enhancement in the energy density of 179.74% and up to 648.35 Wh·kg ^-1.

Polymer mechanochemistry has rapidly evolved since the mid-2000s. Recent advancements highlight the development of mechanophore platforms for the controlled release of bioactive payloads and the exploration of biocompatible activation strategies. These platforms, ranging from furan-maleimide Diels-Alder adducts to disulfide motifs with β-carbonate linkages, demonstrate promising prospects in targeted drug delivery. Additionally, supramolecular assemblies and free radical-generating mechanophores present innovative avenues for potential therapeutic applications. Biocompatible activation methods, notably high-intensity and/or low-intensity focused ultrasound, hold potential for in vivo applications. However, challenges persist in comprehending the fundamental physics of ultrasound and its utilization for activation. Future directions emphasize the importance of simplicity in biocompatible platforms and polymer designs, stability under physiological conditions, and precise control of mechanical activation for enhanced biomedical and clinical utility. Despite the aforementioned chemical and technical obstacles, the outlook for polymer mechanochemistry in biomedical and clinical applications remains promising, urging continued exploration and advancement.

Over the past few decades,   N-sulfonyl hydrazones have been recognized as alternative precursors for hazardous diazo compounds in organic synthesis, allowing for diverse innovative and original chemical transformations that were otherwise difficult to achieve. This critical review summarizes the major advancements in the carbene chemistry of  N-sulfonyl hydrazones. The contents of this review are organized based on research conducted by leading scientists who have made significant contributions to this field. The individual carbene transfer reactions and their mechanisms, as well as the potential applications in the synthesis of natural products and complex bioactive molecules, are thoroughly discussed.