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The replacement of a noble metal catalyst by base metals presents a great challenge for low-temperature CO and volatile organic compounds oxidation. Cu/Ce-based catalysts are expected to achieve this goal with excellent performance, among which the main active sites still need to be further explored. For this reason, CuCe catalysts were further compounded with typical elements (cobalt, Co) to study the main active sites and compositing effect by in-situ enhanced Raman and in-situ ultralow-temperature DRIFTS technologies. The main active site for both CuCe and CuCoCe catalysts was the same Cu–O_V–Ce at the copper–cerium interface, named as asymmetric oxygen vacancy (ASOv). The dispersion of CuO and CeO₂ species was promoted, and the formation energy of ASOv was decreased significantly from 1.502 to 0.854 eV after the addition of Co, which leads to an increase in the ASOv concentration. A small cobalt added can form more Co²⁺ species, improving the activity and stability. The activity of Cu₁Co_0.5Ce₃ catalyst was significantly improved with 100% conversion of CO and toluene at 96 and 227 °C. Here, the ASOv was studied in relative quantification, showing consistency of catalytic activity and ASOv concentration. Meanwhile, the dynamic exchange of ASOv in the reactions was tracked, indicating that the redox equilibrium of ASOv can continuously produce new ASO_V in Cu/Ce-based catalysts that cause long-term catalytic stability. In addition, it is almost difficult for CoCe and CoCu samples to form the ASOv, and the interaction between metals and metals was also weaker than that of CuCe and CuCoCe catalysts.

The N-heterocyclic carbene (NHC)-catalyzed umpolung of aldimines using quinoxalin-2-ones for intermolecular reactions is demonstrated. Specifically, NHC-catalyzed cross-coupling of quinoxalin-2-ones with isatins proceeds via the generation of aza-Breslow intermediates by the addition of carbene to the C═N moiety of quinoxalinones followed by interception with isatins to afford diverse oxindoles in moderate to good yields and good functional group compatibility. Moreover, detailed mechanistic studies involving the isolation and characterization of the imidoyl azoliums (oxidized form of the aza-Breslow intermediates) are provided. Considering the significance of scaffolds bearing both quinoxalin-2-one and oxindole moieties in medicine and natural products, the synthesized molecules employing the NHC-catalyzed imine umpolung strategy are likely to find promising applications.

Zeolite synthesis is known as a difficult-to-control process, with many degrees of freedom that have a partially uncharted impact on the final product. Due to this, many zeolite scientists have regarded the initial mixing (aging) stage as the only time at which the chemical composition of a zeolite synthesis mixture can be impacted without heavily disrupting the delicate equilibria that are at play during crystallization. Recently, however, this view has started to change, with innovative techniques such as charge density mismatch or electro-assisted synthesis showing that the addition of new elements to the reactor midsynthesis might lead to new and surprising outcomes. In this manuscript, we show that by intermittent removal of certain fractions, notably Al-rich solids or Si-rich liquids, from the reaction medium during an interzeolite conversion from FAU-to-CHA (and FAU-to-MFI), one can control the Si/Al ratio of the final product, without heavily impacting the reaction time, particle size, or divalent cation capacity of the final product. This approach was named "split synthesis" and has led to several insights. By removing some Si-rich liquid phase after 40 min of synthesis, the Si/Al ratio of the daughter zeolite was lowered to a value of 20 (starting from 40), while the divalent cation capacity, a performance indicator for several acid and metal-catalyzed reactions, was kept maximized. On the other hand, when Al-rich solids were removed after 40 min (and in some cases colloidal silica was supplemented), we were able to rapidly synthesize small SSZ-13 zeolites with Si/Al ratios up to 180. These high-Si SSZ-13 zeolites had particle sizes in the range 100-150 nm and are traditionally difficult to crystallize in hydroxide medium. They showed a great olefin yield (6%) in the conversion of CO₂ and H₂ with ZnZrOx as cocatalyst.

The C–N bonded aromatic compounds have demonstrated potential applications in energetic materials, polymers, agrochemicals, and medicinal chemistry. Developing improved methodologies for the streamlined and economical generation of C–N bonds is highly sought-after. In this study, an efficient strategy was developed to construct C–N bonded bis-heterocyclic compounds. A total of 26 substrates with different functional groups substituted azoles were selected to react with 1,3,4-trinitropyrazole. The results demonstrate that the C–N coupling reaction is predominantly influenced by the pK_a of the substrates. The relationships between the substrates and C–N coupling products were meticulously investigated and determined. Among those products, compounds 3a–3d exhibit high thermostability and comparable detonation properties to that of RDX, indicating significant potential for use as secondary explosives. The method presented in this work may also serve as a powerful toolkit to design and synthesize C–N bonded bis-heterocyclic compounds in the domains of medicinal chemistry and organic materials.

The C-N bonded aromatic compounds have demonstrated potential applications in energetic materials, polymers, agrochemicals, and medicinal chemistry. Developing improved methodologies for the streamlined and economical generation of C-N bonds is highly sought-after. In this study, an efficient strategy was developed to construct C-N bonded bis-heterocyclic compounds. A total of 26 substrates with different functional groups substituted azoles were selected to react with 1,3,4-trinitropyrazole. The results demonstrate that the C-N coupling reaction is predominantly influenced by the pK _a of the substrates. The relationships between the substrates and C-N coupling products were meticulously investigated and determined. Among those products, compounds 3a-3d exhibit high thermostability and comparable detonation properties to that of RDX, indicating significant potential for use as secondary explosives. The method presented in this work may also serve as a powerful toolkit to design and synthesize C-N bonded bis-heterocyclic compounds in the domains of medicinal chemistry and organic materials.

Through the prosperity of organofluorine chemistry in modern organic synthesis, perfluorinated organic compounds are now abundant and widely available. Consequently, these substances become attractive starting materials for the production of complex, multifunctional fluorinated molecules. However, the inherent challenges associated with the activation and discrimination of the C-F bonds typically lead to overdefluorination as well as functional group incompatibility. To address these problems, our group utilized a rationally designed organophosphorus reagent that promoted mild and selective manipulation of a single C-F bond in trifluoromethyl and pentafluoroethyl ketones via an interrupted Perkow-type reaction, which allowed the replacement of fluorine with more labile and synthetically versatile congeners such as chlorine, bromine, and iodine. The resulting α-haloperfluoroketones have two reactive units with orthogonal properties that would be suitable for the subsequent structural diversification. DFT calculations identified the favorable P-F interaction as the crucial factor from both thermodynamic and kinetic viewpoints.

Through the prosperity of organofluorine chemistry in modern organic synthesis, perfluorinated organic compounds are now abundant and widely available. Consequently, these substances become attractive starting materials for the production of complex, multifunctional fluorinated molecules. However, the inherent challenges associated with the activation and discrimination of the C–F bonds typically lead to overdefluorination as well as functional group incompatibility. To address these problems, our group utilized a rationally designed organophosphorus reagent that promoted mild and selective manipulation of a single C–F bond in trifluoromethyl and pentafluoroethyl ketones via an interrupted Perkow-type reaction, which allowed the replacement of fluorine with more labile and synthetically versatile congeners such as chlorine, bromine, and iodine. The resulting α-haloperfluoroketones have two reactive units with orthogonal properties that would be suitable for the subsequent structural diversification. DFT calculations identified the favorable P–F interaction as the crucial factor from both thermodynamic and kinetic viewpoints.

Zeolite synthesis is known as a difficult-to-control process, with many degrees of freedom that have a partially uncharted impact on the final product. Due to this, many zeolite scientists have regarded the initial mixing (aging) stage as the only time at which the chemical composition of a zeolite synthesis mixture can be impacted without heavily disrupting the delicate equilibria that are at play during crystallization. Recently, however, this view has started to change, with innovative techniques such as charge density mismatch or electro-assisted synthesis showing that the addition of new elements to the reactor midsynthesis might lead to new and surprising outcomes. In this manuscript, we show that by intermittent removal of certain fractions, notably Al-rich solids or Si-rich liquids, from the reaction medium during an interzeolite conversion from FAU-to-CHA (and FAU-to-MFI), one can control the Si/Al ratio of the final product, without heavily impacting the reaction time, particle size, or divalent cation capacity of the final product. This approach was named “split synthesis” and has led to several insights. By removing some Si-rich liquid phase after 40 min of synthesis, the Si/Al ratio of the daughter zeolite was lowered to a value of 20 (starting from 40), while the divalent cation capacity, a performance indicator for several acid and metal-catalyzed reactions, was kept maximized. On the other hand, when Al-rich solids were removed after 40 min (and in some cases colloidal silica was supplemented), we were able to rapidly synthesize small SSZ-13 zeolites with Si/Al ratios up to 180. These high-Si SSZ-13 zeolites had particle sizes in the range 100–150 nm and are traditionally difficult to crystallize in hydroxide medium. They showed a great olefin yield (6%) in the conversion of CO₂ and H₂ with ZnZrOx as cocatalyst.