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In this work, highly dispersed cobalt oxide nanoparticles on SiO2 support were prepared by a facile impregnation method and explored for aerobic selective oxidation of cyclohexene to 2-cyclohexene-1-one under base-free conditions. Among various compositions of Co3O4/SiO2 catalysts (0.5 to 5 wt% Co3O4) investigated, a 1 wt% Co3O4/SiO2 catalyst showed superior cyclohexene conversion with excellent selectivity to 2-cyclohexene-1-one. The synthesized catalysts were characterized by various physiochemical techniques namely, powder XRD, N2 physisorption, Raman spectroscopy, UV–Vis DRS, FTIR spectroscopy, XPS, FE-SEM, and HR-TEM. As revealed by various characterization results, the 1 wt% Co3O4/SiO2 catalyst shows better catalytic performance due to a more specific surface area and a high dispersion of Co3O4 nanoparticles on the SiO2 surface. Various reaction parameters like temperature, reaction time, amount of catalyst, oxidant, and solvent were also studied to optimize the reaction conditions. Further, the reusability of the catalyst was also tested up to five cycles and found to be stable with a negligible variation in the activity. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: A mechanistically distinctive visible‐light‐promoted metal‐free aerobic oxidation of alkenyl silanes with alcohols was disclosed to efficiently construct α‐alkoxy ketones under mild conditions. The primary, secondary, and tertiary alcohols could be used as reactants. The protocol could be carried out on a gram‐scale. Various derivatizations of products could be conducted. Mechanistic studies indicated the reaction was initiated by single‐electron oxidation of the alkenyl silanes, rather than radical addition to alkenyl silanes. [ABSTRACT FROM AUTHOR]

In recent years, several physicochemical methods have been proposed for decolourising textile dyes; however, few have been adopted by the textile industry because of factors such as high cost, low efficiency, and limited applicability to a wide range of dyes. The current study focuses on synthesising algae-mediated Cu and CuO nanocatalysts (Alg-Cu and Alg-CuO) using natural waste materials from green algae. The synthesised Alg-CuO nanocatalyst was characterised and confirmed using SEM, TEM, UV, FT-IR, XRD, XPS, GC-MS, and TGA. An innovative and efficient technique for decolourising dyes through aerobic oxidation was implemented in industrial wastewater treatment. Various hydroxylamine substrates were successfully transformed into the desired aldehydes using an Alg-CuO nanocatalyst. In the process of aerobic oxidation, 2-(2-amino-ethyl)-aminoethanol can be converted into 2-(2-amino-ethyl)acetaldehyde, resulting in 96% product conversion within 4 min. In addition, the synthesised Alg-CuO nanocatalyst was used to investigate the dye decolourisation process using CBB G250 dye. The Alg-CuO nanocatalyst exhibited excellent decolourisation properties; for 20 min, 85% decolourisation of the CBB G250 dye was achieved. As a result, green synthesis is a viable medium for producing Alg-CuO nanocatalysts with high bond energies for dye decolourisation. Finally, the dye and Alg-CuO nanocatalyst was separated and reused for the following process. This method has been used for industrial wastewater treatment. [ABSTRACT FROM AUTHOR]

The aerobic oxidation of 5‐hydroxymethylfurfural (HMF) into 2,5‐furandicarboxylic acid (FDCA), a bio‐based plastic monomer, is an important process for the valorization of biomass. Here, manganese oxides of various oxidation states with identical morphologies and similar surface areas were synthesized by introducing oxygen vacancy sites, and they were investigated as heterogeneous catalysts for HMF oxidation. Mn2O3 exhibited a remarkable catalytic efficiency due to synergistic effect of the oxidation state of metal moieties, the basicity of the catalyst, and oxygen mobility of the oxide materials under basic condition. [ABSTRACT FROM AUTHOR]

The commercially available 3,4,9,10‐perylenetetracarboxylic diimide (PTCDI) acted as a heterogeneous catalyst to catalyze aerobic oxidative synthesis of benzimidazoles, benzothiazoles, and quinoxalines from o‐substituted aniline derivatives and primary amines in high yields with oxygen as the terminal oxidant. The gram scale reaction and reusability (up to six cycles) of the PTCDI catalyst were also successful and would greatly benefit industrial applications. [ABSTRACT FROM AUTHOR]

The aerobic ring‐opening oxidation of cyclopropanols catalyzed by copper complexes was systematically investigated, with a focus on the effect of nitrogen ligands on the distribution of oxidation products. This study led to the development of a new synthesis of β‐aminoketones and β‐enaminones from cyclopropanols, where product specificity is tuned through ligand and solvent selection. β‐Aminoketones were prepared in 34–99% yields by copper(II) acetate‐catalyzed aerobic oxidation of cyclopropanols in the presence of nucleophilic secondary aliphatic amines. In contrast, bipyridine‐ligated copper catalysts resulted in the generation of β‐enaminones in 36–86% yields, presumably via the Kornblum‐DeLaMare rearrangement of intermediate 1,2‐dioxolanes. [ABSTRACT FROM AUTHOR]

Our novel binuclear complex-anchored Ru(III) catalyst, designed and assembled by sonicating 2,2′-(4,6-dihydroxy-1,3-phenylene)bis(1H-benzo[d]imidazole-4-carboxylic acid), Ru(DMSO)4Cl2 and 4-methylpyridine, demonstrates remarkable efficiency and selectivity. It promotes one-pot reactions, including active methylenes and benzyl alcohols in water, via a tandem aerobic oxidation/Knoevenagel condensation process, yielding benzylidene malononitrile in excellent yields. The catalyst's ability to oxidize benzyl alcohols to aldehydes, which then undergo Knoevenagel condensation with active methylenes, makes it a multifunctional catalyst. Notably, the catalyst can be successfully retrieved and recycled for five successive rounds with no significant decrease in catalytic efficiency. The ICP study showed that no catalyst leaching was observed, indicating that the designed catalyst is indeed heterogeneous. The Ru catalyst outperformed other documented catalysts in terms of lower dose, shorter duration, decreased working temperature, and the absence of dangerous additives. This demonstrates the catalyst's robustness and sustainability, making it a promising candidate for future organic conversions and industrial uses. [ABSTRACT FROM AUTHOR]

A highly efficient, low-cost Cu-based catalytic system has been developed, which utilizes a combination of charcoal-supported Cu0 nanoparticles and pyridine as a catalyst for the aerobic oxidation homocoupling of terminal alkynes. This system facilitates the smooth aerobic oxidation of a series of terminal alkynes using oxygen as the oxidant, which results in the formation of corresponding 1,3-conjugated diynes, and water is the sole byproduct. Furthermore, the catalyst has demonstrated good reusability, maintaining its performance for up to five cycles. [ABSTRACT FROM AUTHOR]

A promising CeO2‐Co3O4 (9 : 1 mole ratio based on oxides) non‐noble metal based mixed oxide catalyst was explored for selective oxidation of vanillyl alcohol with molecular oxygen to produce vanillin under atmosphere pressure. In particular, to enhance its efficiency, this catalyst was prepared by adopting different preparation methods namely, template assisted, coprecipitation with and without surfactant, wet‐impregnation, and solution combustion. The prepared catalysts were characterized by XRD, Raman, BET surface area, ICP‐OES, FE‐SEM, HR‐TEM, H2‐TPR, and XPS. Among various catalysts investigated, the template assisted synthesized catalyst exhibited superior activity (100 % conversion and selectivity) and high stability. The better activity of this catalyst was found to be due to reduced crystallite size, high specific surface area (92 m2/g), more surface oxygen, and improved redox behaviour as confirmed from XRD, BET surface area, XPS, and H2‐TPR analysis, respectively. The stability of the catalyst was tested by reusability test and was observed that there is not much decrease in the catalytic activity up to five cycles. Further, the catalytic activity was optimized by varying the reaction parameters such as time, solvent, temperature, and catalyst weight. [ABSTRACT FROM AUTHOR]

The synthesis of sulfoxides has long attracted considerable interest due to their pivotal role in organic synthesis, pharmaceutics and environmental protection. Oxidation of the corresponding sulfides is recognized as the most effective strategy. Traditional oxidation methods, however, fall short of the growing demands of green chemistry. Photocatalytic aerobic oxidation has thus garnered attention, employing the greenest and most sustainable oxidants—oxygen or air—and sunlight as the energy source. Nevertheless, these reactions are typically conducted in potentially pollutive organic solvents rather than in the greenest solvent, water. To facilitate this organic transformation in aqueous phase, molecular reactors that can encapsulate reactants within their confined pores and facilitate photocatalytic reactions have been developed recently. This Concept article summarizes the development of molecular reactors for the photocatalytic oxidation of sulfides and provides perspectives for the design and construction of effective photocatalytic molecular reactors. [ABSTRACT FROM AUTHOR]

Although the introduction of plastics has improved humanity's everyday life, the fast accumulation of plastic waste, including microplastics and nanoplastics, have created numerous problems with recent studies highlighting their involvement in various aspects of our lives. Upcycling of plastics, the conversion of plastic waste to high‐added value chemicals, is a way to combat plastic waste that is receiving increased attention. Herein, we describe a novel aerobic photochemical process for the upcycling of real‐life polystyrene‐based plastics into benzoic acid. A new process employing a thioxanthone‐derivative, in combination with N‐bromosuccinimide, under ambient air and 390 nm irradiation is capable of upcycling real‐life polystyrene‐derived products in benzoic acid in yields varying from 24–54 %. [ABSTRACT FROM AUTHOR]

In this study, ω-3-Cu and ω-3-CuO nanocatalysts were investigated for industrial environmental issues. Nowadays, green methodology is very important for addressing industrial environmental issues. In this regard, the current study focuses on ω-3-Cu and ω-3-CuO used for aerobic oxidation and dye decolourization via an eco-friendly approach. The synthesised ω-3-Cu and ω-3-CuO nanocatalysts were characterised using FT-IR, UV, XRD, TEM, GC–MS, 1H and 13C NMR. The results showed that the prepared ω-3-Cu catalyst was almost spherical with forms and sizes typically less than 20 nm and the ω-3-CuO nanocatalyst 10 nm. The ω-3 Cu and ω-3-CuO nanocatalysts were investigated for the conversion of pentan-2-ol into pentan-2-one, which was observed by GC–MS analysis. The ω-3-CuO nanocatalyst decolourised the Brilliant Blue dye more quickly (100% in 30 min) than ω-3-Cu (85% in 60 min) and ω-3 (no colour in 60 min), and Rhodamine B was not decolourised because our ω-3-Cu and ω-3-CuO nanocatalysts inactivated the rhodamine B dye. The aerobic oxidation process using the ω-3-CuO nanocatalyst as the end product of pentan-2-one resulted in a retention time of 30.33. To the best of our knowledge, ω-3-Cu and ω-3-CuO nanocatalysts have not been documented for their application in decolourisation and aerobic oxidation. By highlighting the potential use for the continued advancement and innovation of ω-3-CuO nanocatalysts in the long-term future, cost-effective and eco-friendly methods for producing reusable ω-3-CuO nanocatalysts have the potential to be applied in advanced technical fields, particularly in the areas of dye decolourisation and aerobic oxidation. Finally, we successfully accomplished these processes using the ω-3-CuO nanocatalyst. The ω-3-CuO nanocatalyst evaporated more quickly than the ω-3-Cu and ω-3-CuO nanocatalyst, without any additional energy. ω-3-CuO is the most effective nanocatalyst for dye decolourization and aerobic oxidation (Dual application). ω-3-CuO is used in textile and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

An iron-mediated bromination/cyclization for the synthesis of bromobenzoxazines from olefinic amides has been successfully developed. In this protocol, the simple iron salt FeBr3 was employed as a bromination reagent, giving the bromobenzoxazine products in moderate to excellent yields. This methodology features good functional group tolerance, gram-scale synthesis, and green reaction conditions by the use of air as the terminal oxidant. Preliminary mechanistic studies suggest that a free radical pathway is involved. [ABSTRACT FROM AUTHOR]

This Account presents palladium-complex-catalyzed oxidative couplings mainly developed by the author's group, including oxidative amination and silylation of terminal alkenes, direct oxidative arylation of aromatic compounds, and oxidative difunctionalization of 1,3-dienes. The catalytic cycles in these representative reactions feature re-oxidation of the palladium species with molecular oxygen as the terminal oxidant. Varying the combination of palladium catalyst and re-oxidant enables the formation of a variety of bonds through dehydrogenative cross-coupling reactions. 1 Introduction 2 Oxidative Amination of Terminal Alkenes 3 Direct Oxidative Arylation of Aromatic Compounds 4 Oxidative Silylation of Terminal Alkenes 5 Oxidative Difunctionalization of 1,3-Dienes 6 Conclusions and Perspectives [ABSTRACT FROM AUTHOR]

Liquid-phase oxidation of dearomatized oil distillate from a mixture of Azerbaijan crudes in the presence of homogeneous catalysts based on Mn(II), Cr(III), and Со(II) bromobenzoates was studied. These catalysts allow preparation of synthetic petroleum acids and hydroxy acids in high yield (>40 wt %). The influence of the kind of the catalyst on the composition of the oxidation products was examined. Manganese(II) bromobenzoate showed the highest catalytic activity. We have determined for it the optimum process conditions at the feed rate of 300 L/(kg h) and atmospheric pressure: oxidation time 5 h; catalyst concentration 1 wt %; 140°С. The total yield of petroleum acids under these conditions was 46%. [ABSTRACT FROM AUTHOR]

The first aerobic protocol of direct transformation of p‐methoxybenzyl (PMB) ethers to carboxylic acids efficiently with Fe(NO3)3 ⋅ 9H2O and TEMPO as catalysts at room temperature has been developed. The reaction accommodates C−Br bond, terminal/non‐terminal C−C triple bond, amide, cyano, nitro, ester, and trifluoromethyl groups. Even highly selective oxidative deprotection of different benzylic PMB ethers has been realized. The reaction has been successfully applied to the total synthesis of natural product, (R)‐6‐hydroxy‐7,9‐octadecadiynoic acid, demonstrating the practicality of the method. Based on experimental studies, a possible mechanism involving oxygen‐stabilized benzylic cation has been proposed. [ABSTRACT FROM AUTHOR]

Photocatalysis has been emerging as a green and sustainable approach to chemical synthesis. Fabrication of an effective and robust photocatalyst to achieve efficient photocatalysis under mild conditions is of great significance but still challenging. Herein, taking the versatile typical Cu-(I)-catalyzed clicked reaction, photoresponsive triphenylamine moieties were rationally incorporated into a triazole-linked porous organic polymer (POP), TATPA-POP, for application in a photocatalytic reaction. Analyses not only confirmed the successful construction of the triazole-linked POP but also showed its stability, nanosized porosity, and semiconductor features. Electron paramagnetic resonance (EPR) spectroscopy measurements revealed its ability to trigger the generation of reactive oxygen species (ROS) under light irradiation, making it have a high potential in ROS-involved photocatalytic reactions. The photocatalytic experiments in sulfide aerobic oxidations confirmed that the constructed POP is an effective and recyclable photocatalyst, demonstrating that, by utilizing the versatile click reaction to incorporate organic photochromic groups into POPs, highly effective heterogeneous photocatalysts can be facilely fabricated. [ABSTRACT FROM AUTHOR]

Aerobic oxidation of olefins without any co‐reductant and high temperature was studies in the presence of nano and bulky Fe‐porphyrin in a comparative manner. Nano‐particles of Fe‐porphyrin were obtained via ultrasound irradiation. The results show higher catalytic efficiency of nano‐catalyst (turnover number of 1300) with respect to the bulk catalyst (turnover number of 600) in the oxidation of cyclohexene with molecular oxygen at room temperature. [ABSTRACT FROM AUTHOR]

In the present work, we have synthesized sulfone-bridged tetraphenyl porphyrin, 2D polymer 'P' (C44H28N4OySx)n through a one-pot reaction of tetra(p-bromophenyl) porphyrin, S with sulfur powder in DMF. The polymer 'P' has been further reacted with erythrosine B for the fabrication of composite photocatalyst, C (C65H37N4NaOySx)n using donor– acceptor conjugation protocol. Herein, both compounds (P & C) have been well characterized by MAS 13C-NMR, XPS, IR, powder XRD, TGA, SEM-EDX, UV-Vis spectra, and Cyclic Voltammetry. Due to the low HOMO-LUMO band gap energy, the applicability of the composite photocatalyst (C, 2.1 eV) has been studied in terms of oxidation of sulfide to sulfoxide. The present work shows a promising route for the development of sulfone-bridged 2D porphyrin covalent organic framework (COF) and its composite photocatalyst as well as its usage in photocatalytic sulfoxidation reaction. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS) regulation for single‐atom nanozymes (SAzymes), e.g. Fe−N−C, is a key scientific issue that determines the activity, selectivity, and stability of aerobic reaction. However, the poor understanding of ROS formation mechanism on SAzymes greatly hampers their wider deployment. Herein, inspired by cytochromes P450 affording bound ROS intermediates in O2 activation, we report Fe−N−C containing the same FeN4 but with tunable second‐shell coordination can effectively regulate ROS production pathways. Remarkably, compared to the control Fe−N−C sample, the second‐shell sulfur functionalized Fe−N−C delivered a 2.4‐fold increase of oxidase‐like activity via the bound Fe=O intermediate. Conversely, free ROS (⋅O2−) release was significantly reduced after functionalization, down to only 17 % of that observed for Fe−N−C. The detailed characterizations and theoretical calculations revealed that the second‐shell sulfur functionalization significantly altered the electronic structure of FeN4 sites, leading to an increase of electron density at Fermi level. It enhanced the electron transfer from active sites to the key intermediate *OOH, thereby ultimately determining the type of ROS in aerobic oxidation process. The proposed Fe−N−Cs with different second‐shell anion were further applied to three aerobic oxidation reactions with enhanced activity, selectivity, and stability. [ABSTRACT FROM AUTHOR]

Metal organic frameworks (MOFs) as semiconductor‐like materials, are considered to be promising photocatalysts for heterogeneous phtotocatalytic oxidation of styrene. Herein, copper‐based MOFs and titanium dioxide composite bifunctional photocatalyst (Cu–benzene‐1,3,5‐tricarboxylate‐titanium dioxide, Cu‐BTC‐TiO2) wereas synthesized, and the selective oxidation of styrene was achieved under mild conditions of oxygen and water. Cu‐BTC‐TiO2 nanoparticles (NPs) exhibited more than three times higher styrene conversion than Cu‐BTC and TiO2 individually under same condition, and the desired product benzaldehyde can be obtained with up to 82% yield. The improved performance may be attributed to the acid site of Cu‐BTC, which is conducive to the adsorption and activation of styrene. In addition, the formation of heterojunction between Cu‐BTC and TiO2 can regulate the band gap of photocatalyst, which is favorable for light absorption, and facilitate the separation, transportation and utilization of photogenerated electron holes. The present protocol features good functional group tolerance, mild reaction conditions, and the reusability of catalyst. [ABSTRACT FROM AUTHOR]

In the latest years, the concentration levels of certain metals and metalloids in the sediments of the Galician Rías have shown an increasing trend (e.g., As, Zn, Cu, Pb, Hg). These areas are also characterized by their richness in nutrients and their great aquaculture or mariculture activity, with the presence of more than 3500 mussel rafts in the Rías Baixas. The inner areas of the Galician Rías are subjected to activities that resuspend the sediment such as high levels of maritime traffic and dredging or cleaning operations. It is likely that a transfer of these elements to the water column happens during the resuspension of sediments caused by natural events or anthropogenic activities. In this study, selected samples of surface sediments of the Ría de Pontevedra (NW Spain) were subjected to a procedure of aerobic oxidation to determine the concentration of some elements (Fe, Mn, Cu, Cr, Pb, Hg, and Zn) released from the sediment to the aqueous phase. The experiment was carried out within 5 days. Measurements of pH and total concentration were taken both in water and sediment samples. Furthermore, speciation of trace elements was carried out in the sediment samples. Trace element concentrations were lower in the sediments during aerobic oxidation, being released to the aqueous phase. From an environmental point of view, Cu was the only trace element released in quantities that may be toxic for the organisms in the area. This problem of sediment oxidation related to dredging activities or natural storm conditions should be considered in environmental impact studies and transferred to stakeholders. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) with a donor‐acceptor (D−A) architecture have been investigated as prospective semiconducting materials, particularly for photocatalytic processes. The incorporation of electron donating and accepting moieties into the COF backbone creates nano heterojunctions, enhancing efficient light absorption, charge separation, and charge transport. Herein, three pyrene‐based COFs were well designed for the aerobic coupling of amines under air atmosphere with blue‐LED irradiation. Among the three COFs, the Py‐Por‐COF with D−A structure exhibits the highest photocatalytic performance and demonstrates a remarkable apparent quantum efficiency of 11.3 % at 420 nm. In addition, the Py‐Por‐COF maintains a good level of crystallinity and high yield even undergone four cycles, showcasing the exceptional potential of D−A structure COFs in the field of photocatalytic organic transformation. [ABSTRACT FROM AUTHOR]

The Mn(III)-based oxidation of 1,3-indanedione (1) with 1,1-diarylethenes 2a–c effectively proceeded in boiling AcOH to produce 2,2-bis(vinyl)indanediones 5a–c and 1,2'-spirobi[indene]-1',3'-diones 6a–c via the formation of 2,2-bis(2-acetoxyethyl)indanedione 3 and acetoxyindeno[1,2-b]furan-4-one 4 intermediates. On the other hand, the Mn(III)-based aerobic oxidation of 1a with 2a at room temperature resulted in bis(endoperoxide) 8a and endoperoxypropellane 9a via the production of mono(endoperoxide) 7a. The plausible reaction pathways were also discussed. [ABSTRACT FROM AUTHOR]

The development of efficient and robust metal nanoparticle catalysts for the aerobic oxidation of benzyl alcohol is crucial for advancing green chemistry. This study presents a class of ceria nanoparticle catalysts, designated as Ce-NC/CFMX-T, where "T" denotes the pyrolysis temperature. These catalysts are synthesized by pyrolyzing a mixture of Ce-MOF-801/CFMX and dicyandiamide at high temperatures, aimed at the liquid-phase aerobic oxidation of 4-methoxybenzyl alcohol to 4-methoxybenzaldehyde, using molecular oxygen as the oxidizing agent and avoiding harmful additives or bases. Among the synthesized catalysts, Ce-NC/CFMX-973 exhibited exceptional catalytic efficiency, achieving over 99.9% conversion of 4-methoxybenzyl alcohol and complete selectivity for 4-methoxybenzaldehyde. This performance was achieved under moderate conditions, using xylene as the solvent at 373 K over 8 h and an oxygen pressure of 1 atm. Kinetic analysis revealed that the activation energy for oxidizing 4-methoxybenzyl alcohol using Ce-NC/CFMX-973 was 68.5 ± 3.0 kJ/mol, which is lower than the values observed for Ce-C/CFMX-973, Ce-NC-973, and Ce-C-973. The remarkable catalytic performance of the Ce-NC/CFMX-973 catalyst is attributed to the synergistic effects between CeO2 nanoparticles and oxygen vacancies, along with the support's balanced acidity and basicity properties. [ABSTRACT FROM AUTHOR]

Kisspeptin signaling regulates energy homeostasis. Adiposity is the principal source and receiver of peripheral Kisspeptin, and adipose Kiss1 metastasis suppressor (Kiss1) gene expression is stimulated by exercise. However, whether the adipose Kiss1 gene regulates energy homeostasis and plays a role in adaptive alterations during prolonged exercise remains unknown. Here, we investigated the role of Kiss1 role in mice and adipose tissues and the adaptive changes it induces after exercise, using adipose‐specific Kiss1 knockout (Kiss1adipoq−/−) and adeno‐associated virus‐induced adipose tissue Kiss1‐overexpressing (Kiss1adipoq over) mice. We found that adipose‐derived kisspeptin signal regulates lipid and glucose homeostasis to maintain systemic energy homeostasis, but in a sex‐dependent manner, with more pronounced metabolic changes in female mice. Kiss1 regulated adaptive alterations of genes and proteins in tricarboxylic acid (TCA) cycle and oxidative phosphorylation (OxPhos) pathways in female gWAT following prolonged aerobic exercise. We could further show that adipose Kiss1 deficiency leads to reduced peroxisome proliferator‐activated receptor gamma co‐activator 1 alpha (PGC‐1α) protein content of soleus muscle and maximum oxygen uptake (VO2 max) of female mice after prolonged exercise. Therefore, adipose Kisspeptin may be a novel adipokine that increases organ sensitivity to glucose, lipids, and oxygen following exercise. [ABSTRACT FROM AUTHOR]

Optimizing lanthanide catalyst performance with organic ligands often encounters significant challenges, including susceptibility to water or oxygen and complex synthesis pathways. To address these issues, our research focuses on developing inorganic lanthanide clusters with enhanced stability and functionality. In this study, we introduce the [Sm6O(OH)8(H2O)24]I8(H2O)8 cluster (Sm-OC) as a sustainable and efficient catalyst for the aerobic oxidation of thiols under heating conditions. The Sm-OC catalyst demonstrated remarkable stability, outstanding recyclability, and excellent chemoselectivity across a diverse range of functional groups in 38 different tests. Notably, it enables efficient unsymmetrical disulfide synthesis and prevents the formation of over-oxidized by-products, highlighting its superior performance. This Sm-OC catalyst provides a practical and robust tool for the precise construction of versatile disulfides, thus establishing a template for the broader use of lanthanide clusters in organic synthesis. [ABSTRACT FROM AUTHOR]

Solar‐driven upgrading of biomass‐derived 5‐hydroxylmethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) holds great promise for sustainable production of bio‐plastics and resins. However, the process is limited by poor selectivity and sluggish kinetics due to the vertical coordination of HMF at relatively strong metal sites. Here, we purposely developed a Cu(II) porphyrin framework featuring side‐chain incorporated urea linkages, denoted as TBUPP−Cu MOF, to render HMF a weak hydrogen bond at the urea site and flat adsorption via π–π stacking with the benzene moiety. The unique configuration promotes the approaching of −CHO of HMF to the photoexcited porphyrin ring towards kinetically and thermodynamically favourable intermediate formation and subsequent desorption. The charge localisation and orbital energy alignment enable the selective activation of O2 over the porphyrin to generate ⋅O2− and 1O2 instead of highly oxidative H2O2 and ⋅OH via spin‐flip electron transfer, which drive the ambient oxidation of proximal −CHO. The effective utilisation of redox species and circumvented over‐oxidation facilitate a FDCA selectivity of >90 % with a high turnover number of 193 molHMF molCu−1. The facile purification of high‐purity FDCA and zero‐waste recycling of intermediates and durable catalyst feature TBUPP−Cu MOF a promising photo‐oxidation platform towards net‐zero biorefining and organic transformations. [ABSTRACT FROM AUTHOR]

MXenes are two‐dimensional nanomaterials having alternating sheets of one atom‐thick early transition metal layer and one atom‐thick carbide or nitride layer. The external surface contains termination groups, whose nature depends on the etching agent used in the preparation procedure from the MAX phase. The present concept proposes that, due to their composition, the metal‐surface termination groups make MXenes particularly suited as heterogeneous catalysts for some reactions. This proposal comes from the consideration that early transition metal atoms bonded to hydroxyl and oxo groups are a general type of active sites in heterogeneous catalysis and that similar catalytic centers can also be present in the MXene structure. After having presented the concept, we have selected V2C Mxene as an example to illustrate its catalytic activity and to show how the catalytic performance varies when the surface groups are modified. As a test reaction, we selected the aerobic oxidation of indane to the corresponding indanol/indanone mixture using molecular oxygen as terminal oxidizing reagent. Two previously reported procedures to modify the surface groups, namely surface dehydroxylation by thermal treatment under diluted hydrogen flow and surface oxidation with ammonium persulfate to convert some surface groups into oxo groups were used, observing in both cases a decrease in the catalytic activity of V2C. Based on this, VIII/IV‐OH are proposed as catalytic centers in this aerobic oxidation. Overall, the present concept shows the merits of MXenes in heterogeneous catalysis, based on their chemical composition and the surface functionality. [ABSTRACT FROM AUTHOR]

We successfully synthesized a bifunctional alkaline catalyst (Co@CTS-1), on the one hand, which demonstrates exceptional catalytic performance in the aerobic oxidation of alkenes, particularly in the epoxidation of styrene, in the absence of both an initiator and a co-reducing agent, achieving a conversion rate of 74.94%, a selectivity of 71.84% for styrene oxide; on the other hand, the catalyst maintained its high activity throughout a cyclic reaction run lasting up to 2500 min, demonstrating exceptional stability in the epoxidation of styrene. The Co@CTS-1 catalyst utilizes TS-1 as the carrier, and it is modified with cobalt and cerium elements. Through the embedding of cobalt elements within the TS-1 cage, the catalyst gains the ability to activate O2, and by inserting cerium elements into the atomic positions of silicon, the conversion rate is further enhanced. This encapsulated structure stabilizes cobalt nanoparticles, overcoming the short lifespan issues caused by sintering and leaching in conventional supported catalysts. This work provides practical clues for the development and application of novel catalysts, and will inspire the advancement of olefin air epoxidation. [ABSTRACT FROM AUTHOR]

Polyether amines are versatile compounds characterized by a flexible structure, consisting of polyoxypropylene and polyoxyethylene as the backbone, with amine groups at each end. They have widespread applications in various industrial processes and daily life. Despite their versatility, the utilization of polyether amines as base catalysts is rare. In this study, one kind of three-arm polyether amine 1 was employed as an environmentally friendly, cost-effective catalyst for the aerobic oxidation of thiophenols, leading to the synthesis of disulfides. The oxidative coupling of thiols serves as a fundamental pathway for the production of disulfides, which are vital in both chemical and biological processes. In contrast to known methods for thiol oxidation, this polyether amine-based catalytic process eliminates the need for expensive stoichiometric oxidants and minimizes the formation of over-oxidized by-products. Using a mere 0.5 mol % of the polyether amine 1 as the catalyst, a remarkable > 96% yield was achieved for all 16 tested substrates, encompassing a diverse range of functional groups, under the catalytic aerobic oxidation conditions. Furthermore, it is noteworthy that over 90% of the polyether amine catalyst can be efficiently recovered for reuse without loss of activity, making this a sustainable and cost-effective catalytic approach. [ABSTRACT FROM AUTHOR]

The design of high activity catalyst for the efficiently conversion of 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) gains great interest. The rationally tailoring of electronic structure directly affects the interaction between catalysts and organic substrates, especially molecular oxygen as the oxidant. This work, the bimetallic catalysts AuPd/CeO2 were prepared by the combining method of chemical reduction and photo‐deposition, effectively concerting charge between Au and Pd and forming the electron‐rich state of Au. The increasing of oxygen vacancy concentration of CeO2 by acidic treatment can facilitate the adsorption of HMF for catalysts and enhance the yield of FDCA (99.0 %). Moreover, a series of experiment results combining with density functional theory calculation illustrated that the oxidation performance of catalyst in HMF conversion was strongly related to the electronic state of interfacial Au−Pd−CeO2. Furthermore, the electron‐rich state sites strengthen the adsorption and activation of molecular oxygen, greatly promoting the elimination of β‐hydride for the selective oxidation of 5‐hydroxymethyl‐2‐furancarboxylic acid (HMFCA) to FDCA, accompanied with an outgoing FDCA formation rate of 13.21 mmol ⋅ g−1 ⋅ min−1 at 80 °C. The perception exhibited in this research could be benefit to understanding the effects of electronic state for interfacial sites and designing excellent catalysts for the oxidation of HMF. [ABSTRACT FROM AUTHOR]

The kinetics of the liquid-phase oxidation of cumene (RH) with molecular oxygen in the presence of KMnO4 and N-hydroxysuccinimide (NHSI) is studied. An increase in the reaction rate when adding acetic acid is established. An synergistic effect of KMnO4 and NHSI in aerobic oxidation of RH is found. This can be associated with the formation of C-centered (R⦁) and O-centered (SINO⦁) radicals that participate in the chain initiation stage and the catalysis of the chain propagation stage by the SINO⦁ radical. [ABSTRACT FROM AUTHOR]

Ag(Pd) bimetallic nanostructures (Ag(Pd)NPs) were synthesized using the galvanic replacement of palladium ions with silver nanoparticles. Based on a comparative analysis of the results of scanning electron microscopy, energy dispersive X-ray microanalysis, and X-ray powder diffraction, it was established that the obtained Ag(Pd)NPs can be considered as "core-shell" nanosystems, in which the core is silver, and the shells are palladium nanoparticles with a size of 5–15 nm. Ag(Pd)NPs were studied as catalysts for the aerobic liquid-phase oxidation of benzyl alcohol. The addition of Ag(Pd)NPs to the reaction system accelerates the reaction in 14 times. [ABSTRACT FROM AUTHOR]

Effective and mild activation of O2 is essential but challenging for aerobic oxidation. In heterogeneous catalysis, high-valence manganese oxide (e.g., +4) is known to be active for the oxidation, whereas divalent MnO is ineffective due to its limited capacity to supply surface oxygen and its thermodynamically unstable structure when binding O2 in reaction conditions. Inspired by natural enzymes that rely on divalent Mn2+, we discovered that confining Mn2+ onto the Mn2O3 surface through a dedicated calcination process creates highly active catalysts for the aerobic oxidation of 5-hydroxymethylfurfural, benzyl alcohol, and CO. The Mn2O3-confined Mn2+ is undercoordinated and efficiently mediates O2 activation, resulting in 2–3 orders of magnitude higher activity than Mn2O3 alone. Through low-temperature infrared spectroscopy, we distinguished low-content Mn2+ sites at Mn2O3 surface, which are difficult to be differentiated by X-ray photoelectron spectroscopy. The combination of in-situ energy-dispersive X-ray absorption spectroscopy and X-ray diffraction further provides insights into the formation of the newly identified active Mn2+ sites. By optimizing the calcination step, we were able to increase the catalytic activity threefold further. The finding offers promising frontiers for exploring active oxidation catalysts by utilizing the confinement of Mn2+ and often-ignored calcination skills. [ABSTRACT FROM AUTHOR]

To reduce the pressure on the environment created by the increasing amount of plastic waste, the need to develop suitable plastic recycling methods has become more evident. However, the chemical recycling toolbox for polyethylene (PE), the most abundant type of plastic waste, remains underdeveloped. In this work, analytical methods were developed to explore the possibility to oxidatively convert PE into di‐carboxylic acids as reaction products. A multi‐analytical approach including gas chromatography‐mass spectrometry, gas chromatography‐flame ionization detection, several (2D) nuclear magnetic resonance methods as well as in‐situ transmission infrared spectroscopy was used. This led to a thorough qualitative and quantitative analysis on the product mixture, which extends and clarifies the existing literature. Without a catalyst (thermally) already up to 7 mol % di‐carboxylic acids can be formed. Furthermore, it was found that the majority of the oxidized functionalities are carboxylic acids, (methyl) ketones, γ‐lactones, γ‐ketones and esters. An intra‐molecular hydrogen shift seemed key in the cleavage step and the formation of late‐stage side products. In addition, crosslinking reactions due to esterification reactions seem to limit the di‐carboxylic acid yield. Therefore, these two handles can be taken into account to study and design similar (catalytic) systems for the oxidative conversion of plastic waste. [ABSTRACT FROM AUTHOR]

With the growing popularity of "green chemistry," the selective oxidation of alcohols using water as a reaction medium and oxygen as an oxidant has increased significantly in the last few years. However, the solubility of organic substances and oxygen in water is relatively poor and generates such a large mass transfer resistance, which seriously reduces the efficiency of aqueous phase reaction. This work employed the construction of TEMPO nanoreactors based on thermoresponsive polymers to lower mass transfer resistance and promote the selective oxidation of alcohol. Compared with free TEMPO, it was discovered that the tethered organocatalyst's reactivity in water under air atmosphere was extraordinarily high within the nanostructure. Moreover, the nanoreactors can be easily recovered by increasing the temperature after the reaction, which can recycle up to five times while still being highly active. This work would offer some fresh perspectives on carrying out environmentally friendly reactions and demonstrate an inventive method for multiphase reaction intensification. [ABSTRACT FROM AUTHOR]

Abstract—Aerobic oxidation of organosulfur compounds of petroleum origin by atmospheric oxygen was performed using a heterogeneous catalyst in the form of Fe3O4 nanoparticles. By studying the oxidation of model mixtures (a solution of dibenzothiophene in decalin), the following conditions for the complete oxidation of dibenzothiophene were selected: catalyst weight, 1 mg; temperature 130°C; and time, 180 min. The catalyst remains active throughout five oxidation cycles. Physicochemical studies showed that the phase composition and structure of the catalyst persist after the regeneration stage. [ABSTRACT FROM AUTHOR]