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The contribution of atomic nitrogen is fairly possible in plasma-assisted catalytic synthesis of ammonia since it has high adsorption probabilities on solid surfaces. On the other hand, recently, the contribution of vibrational excited molecular nitrogen to ammonia synthesis has been discussed. In this work, we compared the fluxes of atomic nitrogen and vibrational excited molecular nitrogen with the rate of plasma-assisted ammonia synthesis. We employed an atmospheric-pressure nitrogen plasma jet, and the spatial afterglow of the plasma jet and a hydrogen flow irradiated the surface of a ruthenium catalyst. The fluxes of atomic nitrogen and vibrational excited molecular nitrogen were measured by two-photon absorption laser-induced fluorescence spectroscopy and laser Raman scattering, respectively. The synthesis rate of ammonia had a positive correlation with the flux of vibrational excited molecular nitrogen, while the variation of the synthesis rate with the gas flow rate was opposite to the flux of atomic nitrogen. The experimental results indicate the contribution of vibrational excited molecular nitrogen to the synthesis of ammonia using the atmospheric-pressure plasma, where the flux of vibrational excited molecular nitrogen is more than four orders of magnitude higher than that of atomic nitrogen. [ABSTRACT FROM AUTHOR]

Two new supramolecular photocatalysts made of covalently linked Ru(II) polypyridine chromophore subunits ([Ru(bpy)3]2+-type species; bpy = 2,2′-bipyridine) and [RuL(pic)2] (L = 2,2′-bipyridine-6,6′-dicarboxylic acid; pic = 4-picoline) water oxidation catalyst subunits have been prepared. The new species, 1 and 2, contain chromophore and catalyst subunits in the molecular ratios 1:1 and 1:2, respectively. The model chromophore species [Ru(bpy)2(L1)]2+ (RuP1; L1=4-[2-(4-pyridyl)-2-hydroxyethyl]-4-methyl-2,2′-bipyridine) and [Ru(bpy)2(L2)]2+ (RuP2; L2 = 4,4′-bis[2-(4-pyridyl)-2-hydroxyethyl]-2,2′-bipyridine) have also been prepared. The absorption spectra, oxidation behavior, and luminescent properties of 1 and 2 have been studied, and the results indicate that each subunit largely maintains its own properties in the supramolecular species. However, the luminescence of the chromophore subunits is significantly quenched in 1 and 2 in comparison with the luminescence of the respective model species. Both 1 and 2 exhibit catalytic water oxidation in the presence of cerium ammonium nitrate, exhibiting an I2M mechanism, with a better efficiency than the known catalyst [RuL(pic)2] under the same experimental conditions. Upon light irradiation, in the presence of persulfate as a sacrificial acceptor agent, 1 and 2 are more efficient photocatalysts than a system made of separated [Ru(bpy)3]2+ and [RuL(pic)2] species, highlighting the advantage of using multicomponent, supramolecular species with respect to isolated species. The O–O bond formation step is I2M, even in the photo-driven process. The photocatalytic process of 2 is more efficient than that of 1, with the turnover frequency reaching a value of 1.2 s−1. A possible reason could be an increased local concentration of catalytic subunits in the needed bimolecular assembly required for the I2M mechanism in 2 with respect to 1, a consequence of the presence of two catalytic subunits in each multicomponent species 2. [ABSTRACT FROM AUTHOR]

The catalytic hydrogenation of biomass-derived chemicals is essential in chemical industry due to the growing demand for sustainable and renewable energy sources. In this study, we present a comprehensive theoretical investigation regarding the hydrogenation of glycolaldehyde to ethylene glycol over a Ru/C catalyst by employing density functional theory and ab initio molecular dynamics simulations. With inclusion of explicit solvation, we have demonstrated that the glycolaldehyde hydrogenation is significantly improved due to the fast proton transfer through the hydrogen bond network. The enhanced activity could be attributed to the participation of the solvent water as the hydrogen source and the highly positively charged state of a Ru cluster in an aqueous phase, which are critical for the activation of aldehyde groups and proton-assisted hydrogenation. Overall, our findings provide valuable insights into glycolaldehyde hydrogenation over Ru/C catalysts in the aqueous phase, highlighting the importance of solvation effects in the biomass conversion. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Chemical Communications" published in 2024. It includes highlights, feature articles, and communications on various topics related to chemistry. The journal is published by The Royal Society of Chemistry, a leading chemistry community. The contents list provides a range of research articles on topics such as catalysts, perovskites, photoluminescence, and electrocatalysis. [Extracted from the article]

A series of M/NiCo-Ferrite (M: Pt, Pd, Ru, and Rh) nanoparticles were successfully synthesized, through a facile sol–gel auto-combustion followed by impregnation-reduction approach, as a catalyst for hydrogen generation from hydrolysis of NaBH4. All synthesized samples were characterized by XRD, N2 adsorption–desorption method, ICP-OES, FE-SEM, and EDX analysis. Compared to the other samples, it was observed that the Rh/NiCo-Ferrite sample exhibited higher particle distribution and surface area. To evaluate the hydrogen generation rate, the hydrolysis was carried out at a temperature of 35 °C, with an aqueous solution containing 5 wt.% NaBH4 and 3 wt.% NaOH. The experimental findings indicate that the Rh/NiCo-Ferrite sample exhibited a superior rate of hydrogen generation, with an average value of 11,667 mL/min.gcat, compared to the other samples studied. Enhanced catalytic properties may be responsible for its high activity. In addition, the activation energy of hydrolysis of sodium borohydride over the Rh/NiCo-Ferrite sample was 54.5 kJ/mol which is lower than the activation energy of many Ferrite-based catalysts. Moreover, the re-usability test of the Rh/NiCo-Ferrite sample denoted a decline in the catalytic activity after 4 recycling experiments due to the alterations in morphology and the reduction in the quantity of active phase. [ABSTRACT FROM AUTHOR]

A series of a novel CAAC ligands featuring a spiro‐fluorene group have been synthesized and complexed with ruthenium alkylidenes, yielding the corresponding Hoveyda‐type derivatives as a new family of olefin metathesis catalysts. The novel complexes have been characterized by XRD, HRMS and NMR measurements. The synthetised complexes were tested in catalysis and showed good activity in olefin metathesis, as demonstrated on diethyl diallylmalonate and allyl acetate substrates. The unique backbone in the ligand with the large, yet inflexible condensed system renders interesting properties to the catalyst, exemplified by the good catalytic performance and improved Z‐selectivity. In addition, the complex can also serve as a hydrogenation catalyst in a consecutive (one‐pot) reaction. The latter reaction can convert allyl acetate to butane‐1,4‐diol, a valuable chemical intermediate for biodegradable polybutylene succinate (PBS). [ABSTRACT FROM AUTHOR]

Herein we demonstrate an effective and facile end‐capping technique for ring‐opening metathesis polymerization (ROMP) using readily available allyl compounds as a new type of terminating agents. This new type of end‐capping reactions, which are based on the base‐promoted decomposition of ruthenocyclobutane intermediates, introduce diene moiety onto the chain end of ROMP polymers while simultaneously deactivating the ruthenium complex. These termination reactions are highly efficient, typically completing within 1 minute at 0 °C with >95 % end‐capping fidelity. [ABSTRACT FROM AUTHOR]

Developed here is a highly fluorescent organic N,O bidentate BF2 complex from isoxazole in the presence of a Ru(II) catalyst. Herein, the complexation proceeds via a selective N–O cleavage of the isoxazole ring. The complex shows absorption (λmax,abs) in the range of 352–363 nm with an extinction coefficient (ε) in the range of 8000–64 000 M−1 cm−1, and fluorescence emission (λmax,em) in the range of 413–485 nm with a Stokes shift of 61–125 nm having quantum yield up to 33%. Apart from the solution state, the solid BF2 complex 2u exhibits absorption at 405 nm and strong fluorescence emission at 550 nm with a quantum yield of 26.9%. [ABSTRACT FROM AUTHOR]

Due to its abundant resources and advantages in transportation and storage, methane fueled solid oxide fuel cells (SOFCs) are highly needed. In this work, an exceptional internal reforming catalyst comprising in-situ exsolved NiRu bimetallic nanoparticles and oxygen-deficient layered double perovskite LaBaMn 1.6 Ni 0.3 Ru 0.1 O 5+δ (r-LBMNR) was prepared. Compared to the cell with LaBaMn 1.6 Ni 0.4 O 5+δ (r-LBMN) catalyst, the cell with a Ru-doping r-LBMNR catalyst layer, exhibits superior peak power output of 336 mW cm−2 and better durability with a less decay rate of 0.014% per hour in CH 4 fuel. The enhanced electrochemical performance can be attributed to the high oxygen ion and electron conductivities of the catalyst and the coupling of Ni and Ru sites with the oxygen-deficient r-LBMNR matrix This coupling activates CH 4 and H 2 O, promotes the oxidation of C atoms in CH 4 molecules, and enables reversible hydrogen spillover, ultimately leading to the production syngas of CO(g) and H 2 (g). [Display omitted] • Trace Ru-doping facilitating the exsolution of nanoparticles. • LaBaMn 1.6 Ni 0.3 Ru 0.1 O 5+δ was modified with abundant O v and exsolved NiRu alloy. • Cell can operate stably over 220 h with a degradation rate of 0.014% h−1. [ABSTRACT FROM AUTHOR]

The immobilization of Hoveyda–Grubbs form of metathesis catalyst (Z.C.) exhibited simple non-covalent interactions with the mesoporous SBA-15. It was discovered that the Z.C. catalyst worked well to speed up the citronellene ring closing metathesis reaction. Using cyclohexane as a solvent, the citronellene ring closing metathesis reaction was performed at various temperatures. A very low (almost negligible) catalyst leaching was observed. A high turnover number (TON) was obtained by using a very small amount of catalyst. The activation energy was calculated in the case of ring closing metathesis reaction of citronellene at different temperatures. By using the high concentration of citronellene, a high TON was obtained (4674), which indicates that active catalytic centers were not demolished by a large concentration of citronellene molecule. Turnover number (264) was produced when the Ru/substrate molar ratio 1:300 used in the reaction. [ABSTRACT FROM AUTHOR]

Renewable energy‐driven proton exchange membrane water electrolyzer (PEMWE) attracts widespread attention as a zero‐emission and sustainable technology. Oxygen evolution reaction (OER) catalysts with sluggish OER kinetics and rapid deactivation are major obstacles to the widespread commercialization of PEMWE. To date, although various advanced electrocatalysts have been reported to enhance acidic OER performance, Ru/Ir‐based nanomaterials remain the most promising catalysts for PEMWE applications. Therefore, there is an urgent need to develop efficient, stable, and cost‐effective Ru/Ir catalysts. Since the structure‐performance relationship is one of the most important tools for studying the reaction mechanism and constructing the optimal catalytic system. In this review, the recent research progress from the construction of unsaturated sites to gain a deeper understanding of the reaction and deactivation mechanism of catalysts is summarized. First, a general understanding of OER reaction mechanism, catalyst dissolution mechanism, and active site structure is provided. Then, advances in the design and synthesis of advanced acidic OER catalysts are reviewed in terms of the classification of unsaturated active site design, i.e., alloy, core‐shell, single‐atom, and framework structures. Finally, challenges and perspectives are presented for the future development of OER catalysts and renewable energy technologies for hydrogen production. [ABSTRACT FROM AUTHOR]

The Volmer step is considered to play a critical role in the alkaline hydrogen oxidation reaction (HOR) process. However, current research mainly focuses on optimizing the adsorption strength of Hads and OHads, while the importance of maximizing the adsorption interfaces with different adsorbates is rarely addressed. Herein, a multi‐strategy approach is explored by simultaneously incorporating Zn single atoms into Ru lattice and carbon support (denoted as (Zn1Ru)SAA/Zn1‐N‐C) to construct a high activity and stable alkaline HOR catalyst. This novel catalyst achieves an impressive mass activity of up to 4.98 mA µgRu−1 at 50 mV, which surpasses that of Ru/N‐C by 1.9 times and even surpasses that of Pt/C by 7.5 times. In addition, the novel catalyst has superior long‐term stability and CO resistance. Experimental results and theoretical calculations reveal that the unique structure of Zn1Ru)SAA/Zn1‐N‐C not only enhances the catalyst (Ru nanoparticles)‐support interaction, it facilitates the electron transfer between catalyst and support, and further optimizes the adsorption behavior of various intermediates, but also forms distinct micro‐regions of adsorbed H (*H) and adsorbed OH (*OH) on the Ru nanoparticle surface, thereby promoting the Volmer process. The research provides a new understanding of the complex design of advanced alkaline HOR catalysts. [ABSTRACT FROM AUTHOR]

Ammonia (NH3), a cornerstone in the chemical industry, has historically been pivotal for producing various valuable products, notably fertilizers. Its significance is further underscored in the modern energy landscape, where NH3 is seen as a promising medium for hydrogen storage and transportation. However, the conventional Haber–Bosch process, which accounts for approximately 170 million ton of NH3 produced globally each year, is energy‐intensive and environmentally damaging. The electrochemical nitrogen reduction reaction (NRR) emerges as a sustainable alternative that operates in ambient conditions and uses renewable energy sources. Despite its potential, the NRR faces challenges, including the inherent stability of nitrogen and its competition with the hydrogen evolution reaction. Transition metals, especially ruthenium (Ru) and molybdenum (Mo), have demonstrated promise as catalysts, enhancing the efficiency of the NRR. Ru excels in catalytic activity, while Mo offers robustness. Strategies like heteroatom doping are being pursued to mitigate NRR challenges, especially the competing hydrogen evolution reaction. This review delves into the advancements of Ru and Mo‐based catalysts for electrochemical ammonia synthesis, elucidating the NRR mechanisms, and championing the transition towards a greener ammonia economy. It also seeks to elucidate the core principles underpinning the NRR mechanism. This shift aims not only to address challenges inherent to traditional production methods but also to align with the overarching goals of global sustainability. [ABSTRACT FROM AUTHOR]

The direct diastereo‐ and enantioselective Ru(II)‐ catalyzed cyclopropanation reaction of alkenes with ((2‐diazo‐1,1‐difluoroethyl)sulfinyl)benzene was described. The desired enantioenriched PhSO2CF2‐cyclopropanes were obtained in high yields with high diastereo‐ and enantioselectivities in the presence of a chiral ruthenium complex Ru(II)‐Pheox (17–94% yields, >20:1 d.r. and 83:17–98:2 e.r.). The robustness of the approach was showcased and This methodology gave access to chiral 1,2‐trans difluoro‐methylcyclopropanes. [ABSTRACT FROM AUTHOR]

A novel method for the production of a biofuel precursor and additive (γ-valerolactone) using in-situ generated hydrogen is reported. Firstly, a potential non-carbon fuel as hydrogen is generated from water through a photoelectrochemical approach employing a set of TiO 2 nanostructures synthesized by hydrodynamic anodization. Secondly, this system was coupled with a reactor in a way that the hydrogen produced reacts with levulinic acid in the presence of a ruthenium catalyst to yield γ-valerolactone. The preparation procedure of TiO 2 nanostructures was optimized and the influence of factors such as the rotation speed and the anodization media was investigated. The best photoelectrochemical performance corresponds to the nanostructure synthesized in lactic acid and using hydrodynamic conditions at a rotation speed of 1000 rpm. The optimal nanostructure was used as a photocatalyst for hydrogen production by water splitting, with the generated hydrogen being directly used for the transformation of levulinic acid into γ-valerolactone in the presence of a ruthenium catalyst supported on alumina. Using this optimal TiO 2 and the ruthenium catalyst, a yield to γ-valerolactone of 93 % was obtained in only 5 h at 60 °C and atmospheric pressure. [Display omitted] • Optimization of photoelectrochemical water splitting with titania nanostructures. • Tandem process: photoelectrocatalysis and conventional heterogeneous catalysis. • In-situ generated hydrogen for biofuel production. • Clean fuels: hydrogen and γ-valerolactone. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "A robust and porous titanium metal-organic framework for gas adsorption, CO2 capture and conversion" published in the journal Dalton Transactions. The correction notice, numbered 12797, acknowledges an error in the original article but does not provide any specific details about the nature of the error or the correction made. The article itself explores the topic of a titanium metal-organic framework and its potential applications in gas adsorption, CO2 capture, and conversion. The journal, published by The Royal Society of Chemistry, covers a wide range of topics in inorganic chemistry and is a respected resource in the field. [Extracted from the article]

The efficient transformation of chemicals and electricity via electrocatalytic hydrogen evolution reaction (HER) plays a pivotal role in green hydrogen production. Both in academia and industry, the pursuit of designing and fabricating catalysts for HER that are not only efficient and robust but also environmentally friendly is of significant interest. In this work, a ruthenium catalyst doped with nickel was synthesized using a procedure-minimal and solvent-free method facilitated by microwave-assisted pyrolysis. The incorporation of alloying and optimized electronic structures has resulted in Ru-based nanocrystals that change the HER mechanism and enable enhanced activity. The optimal RuNi/C catalyst demonstrates an overpotential of only 15 mV at a current density of 10 mA cm−2, with a Tafel slope of 24 mV dec−1, surpassing the performance of the state-of-the-art Pt/C catalyst. Remarkably, the prepared catalyst exhibits admirable corrosion resistance, making it a highly promising candidate for green hydrogen production through seawater splitting. A ruthenium catalyst doped with nickel is synthesized through a solvent-free microwave treatment, and exhibits a Pt-surpassed activity towards HER. [Display omitted] • A ruthenium catalyst doped with nickel is synthesized via a green method. • The HER mechanism on ruthenium is transferred by the doped nickel. • The optimized catalyst shows a platinum-surpassed activity for HER. • Superior corrosion resistance and durability is achieved for seawater splitting. [ABSTRACT FROM AUTHOR]

Electrocatalytic water splitting is a promising production method for green hydrogen; however, its practical application is limited by the lack of robust catalysts for the cathode hydrogen evolution reaction (HER). Recently, the use of Ru in electrocatalytic HER has become a research hotspot because Ru has a metal–hydrogen bond strength similar to that of Pt – known for its excellent HER activity – but has a lower cost than Pt. Numerous modification strategies are available to further improve the HER activity of metal Ru such as vulcanisation, phosphating and atomisation. The atomisation strategy has attracted much attention owing to its extremely high Ru atomic utilisation efficiency and tunable electronic structures. However, isolated studies could not effectively address the bottlenecks. Therefore, to promote the effective exploration of Ru-based single-atom catalysts and clarify the research status in this field, studies on related topics (e.g. Ru single-atom catalysts, Ru dual-atom catalysts, composite catalysts containing single-atom Ru and Ru nanoparticles) have been systematically and briefly summarised herein. Finally, the research challenges and prospects of Ru-based single-atom catalysts in the HER field have been discussed, which may provide valuable insights for further research. [ABSTRACT FROM AUTHOR]

In this study, we investigated the mechanism of the inactivated hexene hydrogenation reaction catalyzed by a ruthenium (II) complex containing "N‐heterocyclic carbene" (NHC) ligands, specifically SIMes and CBA, using DFT calculations. Our focus was on RuH(OSO2CF3)(CO)(SIMes)(CBA), which exhibits excellent catalytic behavior. We tested the B3LYP‐D3, cam‐B3LYP, and TPSSh functionals. The hydrogenation reaction is initiated by the release of SIMes rather than CBA due to the lower associated dissociation energy. Our findings indicate a reaction mechanism consisting of two consecutive steps, each involving one hydrogen atom migration. The first step, considered as the kinetically limiting transition state, exhibits a Gibbs free activation barrier of 12.9 kcal mol−1. This step involves two asynchronous processes. The first one describes the migration of the ruthenium hydride to the internal carbon of the olefine function, transitioning from π to σ coordination mode, which promotes the formation of a bond between ruthenium and the terminal olefinic carbon. The second process involves the oxidation of ruthenium from Ru(II) to Ru(IV). This oxidation is crucial as it enables the decomposition of the H2 molecule into two hydrogen atoms bonded to the ruthenium atom. The geometrical structures of the Hidden Reaction Intermediate Ru(II) complex and the quasi‐transition state of the second process have been determined by means of the RIRC technique. The second step entails the migration of one of the newly formed hydrides of the Ru(IV) complex to the terminal olefinic carbon, resulting in the release of hexane with a weak activation Gibbs free energy of.8 kcal mol−1. Lastly, we explored the use of dichloromethane as a solvent, considering the PCM model. The presence of the solvent significantly decreases the energy dissociation of SIMes from 17.9 to 9.0 kcal mol−1, providing notable benefits. [ABSTRACT FROM AUTHOR]

Chemical Communications is a journal published by The Royal Society of Chemistry, which is a leading chemistry community. The journal features articles on various topics in the chemical sciences. The current issue includes articles on utilizing trees to produce advanced materials, the synthesis of borylated polyene building blocks, and the use of self-assembling short peptide amphiphiles as delivery agents in antibacterial research. It also includes communications on topics such as the reduction of SO2, the decomposition of ammonia, and the shaping of CPO-27-M through crystallization. The journal aims to provide original discoveries and contribute to scientific progress. [Extracted from the article]

Oxyhydrides have attracted attention as materials with various unique properties derived from lattice hydride ions (H−). However, their instability makes synthesis by conventional thermal synthesis methods difficult, so an appropriate synthesis strategy is required. Here, the mechanochemical synthesis of perovskite oxyhydrides BaREO2H (RE = Y, Sc) for catalyst applications is reported. The formation of BaYO2H is known to be thermodynamically unstable; however, a mechanochemical process that inevitably proceeds under non‐equilibrium conditions enables the synthesis of such a metastable oxyhydride material without any heat treatment. Furthermore, BaScO2H, which is typically obtained at very high temperatures (1000 °C) and pressure (>4 GPa), is successfully synthesized at room temperature by the mechanochemical method. The ammonia synthesis reaction over these oxyhydrides supporting Ru is significantly enhanced at low temperatures, and the ammonia synthesis rates are significantly higher than conventional oxide‐supported Ru catalysts. The mechanochemically synthesized BaREO2H has many anionic electrons with low work function at the site of H− vacancies, which enables strong electron donation to Ru and the storage of excess hydrogen adatoms from the Ru surface that results in high catalytic performance. [ABSTRACT FROM AUTHOR]

A full-scale, 2-D, axially symmetric, heterogeneous, and transient mathematical model is utilized to evaluate the dynamic operation of a honeycomb monolithic reactor during CO 2 methanation. A base case is defined, which considers a step-type functionality for H 2 load reduction (−20%) and a Ni catalyst. The impacts of the catalyst type (Ni vs Ru), the functionality of the H 2 load disturbance, and the monolith's diameter on reactor performance are studied and compared to the base case. Results show that the use of Ru as catalyst, a ramp-type disturbance and a smaller reactor diameter generate a superior dynamic response to the H 2 feed disturbance as well as favorable effects on thermal behavior. This is despite the higher temperature gradient generated when using Ru. These findings suggest that the monolithic reactor is a viable technological option for CO 2 methanation under flow variations, such as those encountered when employing green hydrogen. [Display omitted] • Dynamic operation of a monolithic CO 2 methanation reactor is modeled. • Reactor behavior under a step-type H 2 -Load variation is evaluated. • A better dynamic performance is obtained with a Ru catalyst. • A good reactor response to step and ramp fluctuations of the H 2 load was evidenced. • A significant effect of the reactor diameter on the dynamic control was observed. [ABSTRACT FROM AUTHOR]

The preparation of caprolactam (CPL) from biomass as raw material is a very hot topic of current concern. In this paper, a new way to synthesize CPL from 5-hydroxymethylfurfural (HMF) was proposed, and the catalytic reaction of cyclization of the intermediate 6-hydroxycaproamide (6-HCM) was studied to provide a basis for the synthesis of bio-based CPL. A bimetallic catalyst, Ru–Co/TiO2, was prepared using the impregnation method and characterized using XRD, XPS, H2-TPR, and TEM. The investigation delves into the impact of various parameters, including metal loading, choice of solvent, solvent ratio, catalyst dosage, and reaction time, on the yield of the final product. The findings demonstrate a significant synergistic effect between Ru and Co in the bimetallic Ru5Co6/TiO2 catalyst, leading to improved catalytic performance. Under the optimized reaction conditions (250 °C, 1 MPa N2, 1,4-dioxane: NH3·H2O = 2:1 as the solvent ratio), the conversion rate of 6-HCM reaches 99.0%, with CPL yield of 62.2%. [ABSTRACT FROM AUTHOR]

This work demonstrates that supported ruthenium phosphides (RuP2) are attractive catalysts for selective production of alditols by sugar hydrogenation. In our studies, carbon supported RuP2 with a ruthenium content of 5 wt.– % led to the highest activity in xylose hydrogenation and to nearly 100 % yield for xylitol. ICP‐OES and XRD measurements revealed the stability of this novel RuP2/C catalyst under typical hydrogenation conditions (50 barH2, 120 °C) in aqueous phase. Furthermore, STEM‐EDX illustrated the close proximity of ruthenium and phosphorous on the catalyst site and the formation of nanoparticles in the size of 2–4 nm. The catalyst system was successfully applied for the selective hydrogenation of further sugar substrates, including glucose, fructose, and disaccharides, such as cellobiose and sucrose. Here, the RuP2/C revealed its bifunctional acidic/metallic character, enabling in a tandem reaction the hydrolysis of disaccharides, directly followed by a selective hydrogenation to form sugar alcohols in high yield. [ABSTRACT FROM AUTHOR]

This document is a compilation of contributions to a special issue on catalysts published in the journal Catalysts. The contributions cover various topics related to catalysis, including the hydrodeoxygenation of lignin-derived compounds, the synthesis of bifunctional catalysts, transfer hydrogenation of biomass-like compounds, and the development of multifunctional catalytic systems. Each contribution presents research findings and discusses the implications and potential applications of the respective catalysts. The authors express their gratitude to the editorial team and reviewers for their support and contributions. [Extracted from the article]

Tuning the chemical and structural environment of Ru-based nanomaterials is a major challenge for achieving active and stable hydrogen evolution reaction (HER) electrocatalysis. Here, we anchored ultrafine Ru nanoparticles (with a size of ~4.2 nm) on a hierarchical Ni2P array (Ru/Ni2P) to enable highly efficient HER. The Ni2P promoter weakened the adsorption of proton on Ru sites by accepting electrons from Ru nanoparticles. Moreover, the hierarchical Ni2P endowed Ru catalysts with a large surface area and stable open structure. Consequently, the as-fabricated Ru/Ni2P electrode displayed a low overpotential of 57 and 164 mV at the HER current densities of 10 and 50 mA cm−2, respectively, comparable to the state-of-the-art Pt catalysts. Moreover, the Ru/Ni2P electrode can operate stably for 96 h at 50 mA cm−2 without performance degradation. After pairing with a commercial RuO2 anode, the Ru/Ni2P anode catalyzed overall water splitting at 1.73 V with a current density of 10 mA cm−2, which was 0.16 V lower than its commercial Ni counterpart. In situ Raman studies further revealed the optimized proton adsorption at the Ru-active sites on Ni2P promoter, thus enhancing the electrocatalytic HER performance. [ABSTRACT FROM AUTHOR]

The enormous rise in population, urbanization, industrialization, and improvement in people's living conditions over the past few decades have led to an increase in the consumption of fossil fuels. While there are several strategies to overcome it, such as afforestation, increasing the number of natural sinks, trapping the produced carbon dioxide in exhausted oil wells, and sorption of CO2 on absorbers, all of these are only short-term remedies. However, a long-term solution would be conversion of CO2 into another type of substance. Thereby, reduction of CO2 to generate short chain hydrocarbons like CH3OH, CH4, C2H6, etc. can act as a renewable strategy to produce green energy sources. Reduction of CO2 can be achieved following several pathways which include pyrolysis, chemical-catalysis, electrocatalysis and/or photocatalysis, etc. Among these routes, photocatalytic pathway is more appealing as it is an inherently green approach where solar light can directly convert CO2 to value-added products. During molecular photocatalytic CO2 reduction, typically Ru- or Ir-based photosensitizers are commonly used in presence of a cocatalyst. In this context, metal chalcogenides photocatalysts including CdS, CuS, MoS2, ZnS, ZnTe, and their heterostructures like CdSe/CdS, CdS/CeO2, etc. are made of earth-abundant metals and have received a considerable attention towards CO2 reduction due to their notable photocatalytic efficiency. As it is well known, it is nearly impossible to concurrently satisfy the various performances in a one-step excitation system utilizing a single photocatalyst. As a result, the idea of composite photocatalysts which combine the advantages of many materials emerged, and this trend has become essential and foreseeable. This compact review highlights the application and the engagement of metal chalcogenides which due to their unique properties not only helps in the reduction of CO2 but also plays a vital role in reducing environmental pollution and hence seen as a potential remedy towards the concerned problem. This compact review highlights the application and engagement of metal chalcogenides which due to their unique properties not only helps in the reduction of CO2 but also plays a vital role in reducing environmental pollution. Various metal chalcogenides photocatalysts including CdS, CuS, MoS2, ZnS, ZnTe, and their heterostructures like CdSe/CdS, CdS/CeO2, etc. are made of earth-abundant metals and have received a considerable attention towards CO2 reduction due to their notable photocatalytic efficiency. [ABSTRACT FROM AUTHOR]

Organometallic ruthenium complexes with p-cymene = 1-methyl-4-(1-methylethyl)-benzene and N^N = bidentate polypyridyl ligands constitute interesting candidates with biological and catalytic properties. Towards this aim, we have synthesized four ruthenium(II)–arene complexes of the type [Ru(η6-p-cymene)(N^N)Cl][X] (N^N = Br-Qpy = 6-bromo-4-phenyl-2-pyridin-2-yl-quinoline, X = Cl− (1a); PF6− (1b); N^N = OH-Ph-Qpy = 4-(4-phenyl-2-(pyridin-2-yl)quinolin-6-yl)phenol, X = Cl− (2a); PF6− (2b)). This is the first report of ruthenium(II) p-cymene complexes incorporating substituted pyridine–quinoline ligands, with –Br and –C6H4OH groups in the 6-position of quinoline. We also refer to the cytotoxicity of the ligands and their possible effect of modulating the activity of the ruthenium(II) complexes. These were characterized by a combination of spectroscopic methods (ATR-IR, UV–Vis, multinuclear NMR), elemental analysis, and conductivity measurements. The solid-state structure of 2b, determined by single-crystal X-ray diffraction, reveals a three-legged piano-stool geometry. The in vitro cytotoxic activities of the new complexes were evaluated in HEK293T (human embryonic kidney cells) and in HeLa cells (cervical cancer cells), via the MTT assay. Poor in vitro anticancer activities were observed for the HeLa cancer cell line, with 2a being the most potent (IC50 = 75 μΜ). The cytotoxicity of Br-Qpy in HEK293T is comparable to that of cisplatin. Both complexes 1a and 1b successfully catalyze the transfer hydrogenation of benzophenone to benzhydrol by 2-propanol at 82 °C. The catalytic performance of 1a in the ratio of S:Cat:B = 400:1:40 (S = substrate, Cat = catalyst, B = base = KOiPr) leads to a conversion of 94%, within 3 h of reaction. Presumably, catalytic transformation takes place via ruthenium(II) hydride species being the active catalyst. [ABSTRACT FROM AUTHOR]

Porous carbon supported metal catalyst with embedded structure has witnessed the success in enhancing catalyst stability; however, the development of a simple yet efficient strategy to fabricate catalyst with controllable embedding degree is still a great challenge. Herein, we report a facile impregnation-coating-pyrolysis (ICP) strategy to fabricate ultrafine Ru nanoparticles embedded into N-doped porous carbon nanosheets (Ru@CN). Both the dispersion and exposure degree of Ru nanoparticles in Ru@CN catalyst could be efficient controlled through regulating the coating time of carbon precursors. As expected, the obtained Ru@CN catalyst exhibited an acid resistance for the hydrogenation of levulinic acid in an aqueous phase. Specifically, the spent Ru@CN catalyst shows a significant enhancement in catalytic activity compared with fresh one because the fact that part of Ru active sites confined inside carbon support could be liberated during the reaction process. We anticipate that this ICP strategy may provide a new approach to fabricate the embedded catalyst with high hydrothermal stability. [ABSTRACT FROM AUTHOR]

The essential role of metal–support interaction in ammonia synthesis was investigated by using a Pr6O11 supported Ru nanoparticles (NPs) catalyst system. Loading of Ru NPs onto the Pr6O11 support with relatively low surface area yields similar metal dispersion with respect to conventional SiO2 support. The Ru NPs on the Pr6O11 was found to exhibit excellent catalytic performance in ammonia synthesis, superior to free-standing Ru NPs and Ru NPs on conventional SiO2 support. Detailed structure analysis results reveal that the superior activity of Ru/Pr6O11 can be attributed to the enhanced interaction between the Ru NPs and Pr6O11, which can modulate the electronic structure of Ru NPs and trigger catalytic ammonia synthesis over Ru NPs on Pr6O11. Furthermore, nitrogen isotope exchange experiment reveals that superior nitrogen dissociation ability is essential for the excellent activity and intrinsic activity of Ru/Pr6O11 in ammonia synthesis. These findings demonstrate that Pr6O11 can be used as a new kind of support for preparation of efficient Ru-based catalysts for ammonia synthesis, and also open up opportunities for design of Pr6O11 supported metal catalysts for other catalytic reactions. Interaction between the Ru NPs and Pr6O11 can modulate the electronic structure of Ru NPs and trigger catalytic ammonia synthesis over Ru NPs on Pr6O11. [ABSTRACT FROM AUTHOR]

The performance of a set of bimetallic Ru-Co catalysts dispersed on the TiO2 anatase phase, synthesized by the co-deposition–precipitation with urea method, was tested in the CO2 production by the entire oxidation of C3H8. The presence of properly dispersed ruthenium nanoparticles on a Co/TiO2-anatase support was notably favorable for enhancing the C3H8 activity/selectivity. Likewise, an increase in the combined acidity (Brönsted and Lewis) was also observed, and the interaction between Ru0-CoOx species stabilized on TiO2 prompted the C3H8 oxidation at low temperature. The performance of bimetallic Ru-Co/TiO2 catalysts was enhanced by increasing Ru0 species and loading, showing more efficient C3H8 oxidation by the combination of Ru0-CoOx, as revealed by DRIFTS, XPS, H2-TPR, and HAADF-STEM characterization outcomes. The higher acidity of the catalysts containing Ru (1.5 wt%) and Co (3 wt%) as well as the reducibility enhancement of the Ru and Co species led to the best capacity of these catalysts for C3H8 oxidation to CO2 under the experimental conditions employed in this study. [ABSTRACT FROM AUTHOR]

Diarylacetylenes ArC≡CAr featuring condensed aromatic hydrocarbon fragments (Ar) such as naphthalene, anthracene, phenanthrene and pyrene were converted into vinylidene ligands by 1,2‐migration reactions within the coordination sphere of half‐sandwich complexes [MII(dppe)Cp]+ (MII = RuII, FeII). Comparison of the extent of conversion of the alkyne substrates to the vinylidene complexes [Ru{=C=CAr2}(dppe)Cp]+ with those obtained from acetylenes functionalized by smaller groups (H, CH3, Ph) show that the molecular volume (VM) of the migrating group and relief of steric congestion plays a role during the rearrangement process. Conversely, the H‐atoms from the larger condensed ring aryl groups that are in close proximity to the migrating sites also have a significant influence on the efficacy and extent of the reaction by restricting access of the alkyne to the metal center, resulting in a less effective migration reaction. This combination of competing steric factors (acceleration due to relief of steric congestion and restricted access of the alkyne moiety to the reaction site) is exemplified by the facile migration of 1‐pyryl entities and the low yields of vinylidene products formed from 1,2‐bis(9‐anthryl)acetylene. [ABSTRACT FROM AUTHOR]

Electrocatalysis holds the key to enhancing the efficiency and cost-effectiveness of water splitting devices, thereby contributing to the advancement of hydrogen as a clean, sustainable energy carrier. This study focuses on the rational design of Ru nanoparticle catalysts supported on TiN (Ru NPs/TiN) for the hydrogen evolution reaction in alkaline conditions. The as designed catalysts exhibit a high mass activity of 20 A mg−1Ru at an overpotential of 63 mV and long-term stability, surpassing the present benchmarks for commercial electrolyzers. Structural analysis highlights the effective modification of the Ru nanoparticle properties by the TiN substrate, while density functional theory calculations indicate strong adhesion of Ru particles to TiN substrates and advantageous modulation of hydrogen adsorption energies via particle-support interactions. Finally, we assemble an anion exchange membrane electrolyzer using the Ru NPs/TiN as the hydrogen evolution reaction catalyst, which operates at 5 A cm−2 for more than 1000 h with negligible degradation, exceeding the performance requirements for commercial electrolyzers. Our findings contribute to the design of efficient catalysts for water splitting by exploiting particle-support interactions. Designing efficient and stable electrocatalysts for water splitting is of great interest for H2 fuel production. Here, the authors present a Ru nanoparticle catalyst on TiN, achieving 20 A mg−1 Ru at 63 mV in alkaline conditions, and operating at 5 A cm−2 for over 1000 hours in an anion exchange membrane electrolyzer. [ABSTRACT FROM AUTHOR]

Electrocatalytic nitrate reduction to ammonia holds great promise for developing green technologies for electrochemical ammonia energy conversion and storage. Considering that real nitrate resources often exhibit low concentrations, it is challenging to achieve high activity in low-concentration nitrate solutions due to the competing reaction of the hydrogen evolution reaction, let alone considering the catalyst lifetime. Herein, we present a high nitrate reduction performance electrocatalyst based on a Co nanosheet structure with a gradient dispersion of Ru, which yields a high NH3 Faraday efficiency of over 93% at an industrially relevant NH3 current density of 1.0 A/cm2 in 2000 ppm NO3- electrolyte, while maintaining good stability for 720 h under −300 mA/cm2. The electrocatalyst maintains high activity even in 62 ppm NO3- electrolyte. Electrochemical studies, density functional theory, electrochemical in situ Raman, and Fourier-transformed infrared spectroscopy confirm that the gradient concentration design of the catalyst reduces the reaction energy barrier to improve its activity and suppresses the catalyst evolution caused by the expansion of the Co lattice to enhance its stability. The gradient-driven design in this work provides a direction for improving the performance of electrocatalytic nitrate reduction to ammonia. Achieving stable and high-activity nitrate electroreduction to ammonia in low concentrations nitrate is critical but challenging. Here, the authors present a Co-based electrocatalyst with gradient-doped Ru atoms, showing a continuous ammonia production at −1000 mA/cm2 in 2000 ppm nitrate electrolyte. [ABSTRACT FROM AUTHOR]

Ru single-atom catalysts have great potential to replace toxic mercuric chloride in acetylene hydrochlorination. However, long-term catalytic stability remains a grand challenge due to the aggregation of Ru atoms caused by over-chlorination. Herein, we synthesize an asymmetric Ru-In atomic pair with vinyl chloride monomer yield (>99.5%) and stability (>600 h) at a gas hourly space velocity of 180 h−1, far surpassing those of the Ru single-atom counterparts. A combination of experimental and theoretical techniques reveals that there is a strong d-p orbital interaction between Ru and In atoms, which not only enables the selective adsorption of acetylene and hydrogen chloride at different atomic sites but also optimizes the electron configuration of Ru. As a result, the intrinsic energy barrier for vinyl chloride generation is lowered, and the thermodynamics of the chlorination process at the Ru site is switched from exothermal to endothermal due to the change of orbital couplings. This work provides a strategy to prevent the deactivation and depletion of active Ru centers during acetylene hydrochlorination. Stable operation of acetylene hydrochlorination remains a challenge due to over-chlorination of Ru. Here, the authors propose a Ru-In atom pair with d-p orbital coupling that switches the thermodynamics of chlorination process and improves stability. [ABSTRACT FROM AUTHOR]

An electrochemical method with high faradaic efficiency was developed for the ruthenium‐catalyzed C8‐regioselective aroylation of quinoline N‐oxides under oxidant‐free conditions by using aryl α‐ketoacids as the aroylation reagent. A series of 8‐aroylquinoline N‐oxides were effectively synthesized in moderate‐to‐excellent yields. Furthermore, the proposed method was successfully applied to the gram‐scale synthesis of a tubulin polymerization inhibitor. Additionally, a plausible reaction mechanism for the decarboxylation radical acylation was proposed on the basis of the results of cyclic voltammetry and control experiments. Overall, this method provides a novel solution for the C8‐regioselective aroylation of quinoline N‐oxides. [ABSTRACT FROM AUTHOR]

The effectuation of pH‐universal electrocatalysis is highly attractive but still challenging for the hydrogen evolution reaction (HER). It appeals for not only the facilitated electron transport but also the kinetical proton mass transfer. In this study, a via‐hole Ru/MoO2 confined heterostructure is profiled as a metal‐support platform for the electron/mass transfer‐boosted pH‐universal HER studies. It is indicated that the as‐formed Ru─O─Mo bridge can modulate the electronic transport at the interface, and the proton adsorption and transfer are kinetically derived by the intensified metallic Ru─Ru bond. Resultantly, the Ru/MoO2 heterostructure stably attains the Pt‐beyond HER activity with an ultralow overpotential of 9.2 mV at 10 mA cm−2 in 1 m KOH, and also achieves the competitive HER activity and stability in the acidic/neutral electrolytes. Both the experimental and computational results reveal the accelerated HER kinetics is attributable to the intensive mass transfer through the interfacial Ru→MoO2 hydrogen spillover effect. This work opens up the opportunities to rationalize the advanced metal‐support HER electrocatalysts through the interfacial hydrogen spillover effect and metallic bond engineering. [ABSTRACT FROM AUTHOR]

Ruthenium nanoparticles stabilised by an amine‐modified Ordered Mesoporous Silica Immobilized Ionic Liquid (OMSIIL) are efficient catalysts for the partial reduction of nitrobenzene to hydrazobenzene with 100 % selectivity as well as the complete reduction to aniline. High selectivity for the partial reduction of nitrobenzene to hydrazobenzene was obtained when the reaction was conducted in ethanol with 0.5 mol% catalyst and NaBH4 as the hydrogen donor whereas aniline was obtained as the sole product in water when dimethylamine borane (DMAB) was used as the hydrogen donor. Interestingly, while a range of electron poor nitroarenes were reduced to the corresponding hydrazoarene with high selectivities and good conversions, nitroarenes substituted with electron donating groups resulted in complete reduction to the aniline. Composition‐time profiles suggest that reductions conducted in ethanol with sodium borohydride occur via the condensation pathway while those conducted in water using dimethylamine borane as the hydrogen source may well go via the direct pathway. This is the first example of the selective reduction of nitrobenzene to hydrazobenzene using a ruthenium nanoparticle‐based catalyst and the initial TOF of 320 mol nitrobenzene converted mol Ru−1 h−1 for the partial reduction of nitrobenzene to hydrazobenzene is markedly higher than previous literature reports. A study of the catalyst performance as a function of the surface modification revealed that each component has a direct and dramatic effect on the efficacy as RuNPs stabilised by COK‐12 modified with imidazolium‐based ionic liquid and a primary amine gave the highest conversion while selective removal of either component or replacement of the primary amine with a tertiary amine resulted in a marked reduction in efficiency. [ABSTRACT FROM AUTHOR]

The reaction of [Ru(dmso)4Cl2] with a potassium salt of four xanthate (RO–C(＝S)S−; R = Me, Et, iPr and tBu) ligands (depicted as Ln; n = 1–4) in hot methanol afforded a group of mixed-ligand complexes of type [Ru(Ln)2(dmso)2]. The crystal structures of all the four complexes have been determined, which show that the xanthate ligands are bound to the metal center forming four-membered chelates and dmso is coordinated through sulfur and they are mutually cis. The relative thermodynamic stability of this cis and the other possible trans-isomers of these complexes has been assessed with the help of DFT calculations, which have revealed that the cis-isomer is the more stable isomer. The coordinated dmso in the [Ru(Ln)2(dmso)2] complexes could be easily displaced by chelating bidentate ligands (depicted as L′) to furnish complexes of type [Ru(Ln)2(L′)], as demonstrated through isolation of two such complexes, viz. [Ru(L3)2(bpy)] and [Ru(L2)2(phen)] (bpy = 2,2′-bipyridine and phen = 1,10-phenanthroline). The crystal structure of [Ru(L3)2(bpy)] has been determined and the structure of [Ru(L2)2(phen)] has been optimized by the DFT method. The electronic spectra of the four [Ru(Ln)2(dmso)2] complexes and the two derivatives ([Ru(Ln)2(L′)]; n = 3, L′ = bpy; n = 2, L′ = phen), recorded in dichloromethane solutions, show intense absorptions spanning the visible and ultraviolet regions, which have been analyzed by the TDDFT method. The [Ru(Ln)2(dmso)2] complexes are found to serve as efficient catalyst precursors for the acceptorless dehydrogenation of 2-propanol followed by crossed-aldol condensation with substituted benzaldehydes (and related aldehydes), using tert-butoxide as the co-catalyst, producing dibenzylideneacetone derivatives in good yields. [ABSTRACT FROM AUTHOR]

Reaction of a sterically demanding iminophosphorano-phosphine, Ph2PCH2Ph2P＝NAr* (here onwards referred to as PCPNAr*; Ar* = 2,6-dibenzhydryl-4-methylphenyl), (1) with [Ru(η6-p-cymene)Cl2]2 yielded three different types of complex, [RuCl2{(η6-p-cymene)(PCPNAr*)-κ1-P}] (2), [RuCl{(P(O)CPNAr*)(κ2-N,C)(C-η6-arene)}] (3) and [RuCl{(POCP＝NAr*)(κ2-N,C-o)(C-η6-arene)}] (4), depending on the reaction conditions via CH activation, tethered η6-arene coordination, ortho-metallation or P＝N bond cleavage/rearrangement reactions. Interestingly, a similar reaction in CH3CN in the presence of AgBF4 resulted in the insertion of CH3CN into the P＝N bond to form a novel metallacycle [Ru(NCMe)3{(PC2P＝N(CH3)C＝NAr*)-κ3-N,N,P}][BF4]2 (5) containing 4- and 5-membered rings via an aza-Wittig type reaction. Complex 4 showed very good catalytic activity in the transfer hydrogenation of carbonyl compounds. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Chemical Communications" published on July 4, 2024. It includes articles on various topics such as the aggregation and phase separation of a-synuclein in Parkinson's disease, the design of stimuli-responsive materials using cleavable azobenzene linkers, and the selective encapsulation of carboxylic acid dimers. The journal is published by The Royal Society of Chemistry, a leading chemistry community, and covers both natural and synthetic polymers. The document also provides information on the application of polymers and the journal's open access policy. [Extracted from the article]

This work aims at investigating the potential of catalytic membrane reactors (CMRs) for ammonia production from renewable hydrogen. To achieve this objective, computer-aided process simulation is deployed using Aspen plus v14 simulation tool. A 1D model is developed to describe the integration of a ruthenium catalyst into a CMR equipped with inorganic membranes that are selective to NH 3 over N 2 and H 2. First, the CMR performance is studied across a broad spectrum of membrane properties and operating conditions. Subsequently, the CMR model is integrated into several Power-to-Ammonia (PtA) process layouts, which are optimized and techno-economically compared against a traditional PEM-based PtA production process, employing condensation for the purification stage. Key findings at the reactor level confirmed that beyond a selectivity threshold towards hydrogen of 10–20, both the degree of conversion and recovery tend to be generally independent of the membrane's selectivity. However, for producing pure ammonia permeate, highly selective membranes (>1000 towards H 2) depending on the pressure drop are found essential making this alternative elusive based on existing membranes. At the PtA level, results in terms of efficiency indicates that the use of membrane reactor increases the system efficiency by around ∼8% with respect to reference case while ∼15% enhancement is achieved with this process when using SOEC technology. When examining the final Levelized Cost of Ammonia (LCOA), incorporating a membrane reactor in conjunction with condensation separation results in a cost that nearly matches the reference case. Future research should focus on replacing the condensation process with a method of purification at lower pressures. This could potentially further improve efficiency and reduce the cost of the membrane reactor compared to the traditional one. • A reactor model for ammonia production using a ruthenium catalyst-based CMR was developed, analyzing a range of membrane properties and operating conditions. • MR shows over 90% higher ammonia conversion compared to conventional reactors. • The MR increased the system efficiency by around 8% with respect to reference cases. • MR process showed a marginal 2% increase in cost over the reference process. [ABSTRACT FROM AUTHOR]

Ruthenium complexes with facially coordinating tripodal phosphine ligands are privileged catalysts for a broad range of (de-)hydrogenation-based transformations. Among these, C–O bond hydrogenolysis holds potential for the depolymerisation of both the biopolymer lignin and epoxy resins applied in wind turbine blades, aircrafts and more. However, this methodology is poorly understood in mechanistic terms. Here, we present a detailed investigation on the triphos-Ru catalysed C–O bond scission on a molecular level. A combination of experimental, spectroscopical and theoretical studies elucidates the reactivity of the ruthenium trimethylenemethane precatalyst, revealing the key roles of ruthenium phenolates in both catalyst activation as well as the catalytic cycle itself. Furthermore, a Ru(0)/Ru(II) oxidative addition into the C–O bond is disclosed, with a triphos-Ru(0) dihydrogen complex as entry point. With the molecular nature of the operating triphos-Ru species and the thermodynamics and kinetics of the catalysis unravelled, improvements of established methods as well as design of related transformations may become possible. Ruthenium complexes with facially coordinating tripodal phosphine ligands are privileged catalysts for a broad range of (de-)hydrogenation-based transformations but the mechanism remains poorly understood. Here the authors present a detailed investigation on the triphos-Ru catalysed C–O bond scission on a molecular level. [ABSTRACT FROM AUTHOR]

The catalytic efficacy of ruthenium (Ru)-exchanged montmorillonite, a well-established heterogeneous catalyst, was systematically explored to synthesize diverse bis(indolyl)methanes. The developed methodology consistently yielded the desired products with satisfactory to excellent yields, while notable advantages of the proposed approach encompassed minimal reaction times and solvent-free conditions. Furthermore, the method was characterized by its procedural simplicity, facile catalyst synthesis, ready accessibility of the starting materials from commercial sources, and the potential for catalyst recyclability. [ABSTRACT FROM AUTHOR]

Electrocatalytic hydrogen evolution and (S2−) recycling present promising strategies for cost‐effective hydrogen production and simultaneous removal of environmental pollutants. However, the advancement of this technology is hindered by the limited availability of affordable, efficient, and stable catalysts. Herein, the study synthesizes ultrafine ruthenium (Ru) nanoclusters on a substrate of iron molybdenum sulfide (FeMo‐S) nanosheets, creating a new heterointerface catalyst (FeMo‐S/Ru) for the hydrogen evolution reaction (HER) and sulfion oxidation reaction (SOR). Experimental and theoretical calculations suggest that strong electron interactions between Ru nanoclusters and FeMo‐S substrate, optimizing *H adsorption and promoting HER activity on one side while facilitating the production and adsorption of sulfur intermediates on the other side, effectively catalyzing SOR. Additionally, the assembled electrocatalytic coupling system with FeMo‐S/Ru displays an ultralow cell voltage of 0.57 V at 100 mA cm−2, achieving high Faradaic efficiencies (>96%) for H2 production, while also exhibiting remarkable durability over 1 month (838 h). This work paves the way for the development of highly efficient and durable supported catalysts, enabling energy‐saving hydrogen production and environmentally friendly sulfion recycling. [ABSTRACT FROM AUTHOR]

Carboxylates are ideal directing groups because they are widely available, readily cleavable and excellent linchpins for diverse follow-up reactions. However, their use in meta-selective C−H functionalizations remains a substantial unmet catalytic challenge. Herein, we report the ruthenium-catalyzed meta-C–H alkylation of aromatic carboxylic acids with various functionalized alkyl halides. A bidentate N-ligand increases the electron density at the metal center of ortho-benzoate ruthenacycles to the extent that single-electron reductions of alkyl halides can take place. The subsequent addition of alkyl radicals is exclusively directed to the position para to the CAr–Ru bond, i.e., meta to the carboxylate group. The resulting catalytic meta-C−H alkylation extends to a wide range of (hetero)aromatic carboxylic acids including benzofused five-membered ring heteroarenes but no pyridine derivatives in combination with secondary/tertiary alkyl halides, including fluorinated derivatives. It also allows site-selective C5−H alkylation of 1-naphthoic acids. The products are shown to be synthetic hubs en route to meta-alkylated aryl ketones, nitriles, amides, esters and other functionalized products. Carboxylates are ideal directing groups for aryl C–H functionalizations, given their wide availability and relative ease of functional group interconversion; however, their potential in meta-selective functionalizations has not been fully realized. Here, the authors use carboxylates for meta-selective alkylations via ruthenium catalysis. [ABSTRACT FROM AUTHOR]

Developing high‐performance aviation fuel is highly desired for the rapid development of supersonic aircraft. Herein, selective deep hydrogenation of polycyclic aromatics to a high‐density fuel is developed over a Ru‐based catalyst. The influences of strong Ru‐support interaction on tailoring the reaction pathways of acenaphthene hydrogenation were investigated using different oxide supports (SiO2, CeO2, TiO2). Ru/CeO2 and Ru/TiO2 with strong SMSI possess abundant electron‐deficient Ruδ+ species which exhibit a good ability to promote H2 dissociation and increase the isomerization rate of saturated aromatic compounds. Due to the enhanced adsorption of aromatic molecules, Ru/CeO2 (1.30 μmol min−1 g−1) exhibits superior catalytic activity in comparison to Ru/TiO2 (1.25 μmol min−1 g−1) during acenaphthene hydrosaturation, while Ru/TiO2 exhibits the highest isomerization reaction rate (7.60×10−2 μmol min−1 g−1) because of its excellent hydrogen spillover ability and high content of Ruδ+ species. The best catalytic activity with 96 % selectivity of ccc‐perhydroacenaphthene was achieved on Ru/TiO2, and an isomerization mechanism of perhydroacenaphthene isomers was proposed. [ABSTRACT FROM AUTHOR]

Liquid organic hydrogen carrier (LOHC) systems are an excellent alternative to pressurized gas and liquid hydrogen storage technologies due to their high volumetric storage capacities and straightforward adaptation to existing infrastructure. Homogeneous catalysts are promising for the selective and reversible release of hydrogen from LOHC. However, separation from product mixtures and recycling inhibit their use, particularly when comprised of costly low-abundance elements, motivating the development of heterogeneous versions that are more easily recovered and reused. Here, we describe two methods for the heterogenization of molecular Ru catalysts that efficiently dehydrogenate the polyalcohol LOHCs ethylene glycol (EG) and 1,2-propanediol (1,2-PDO). The heterogeneous versions of these catalysts maintain catalytic activity for hydrogen production comparable to the homogeneous complexes, with up to 81% conversion and 99% selectivity. DFT modeling indicates mechanistic similarities for the dehydrogenations of EG and 1,2-PDO, with the rate-limiting steps associated with protonation of the Ru-H bond to form H2 and the alkoxide species coordinated to Ru(II), followed by β-hydride elimination to regenerate the Ru-H bond. Overall, the data suggest these heterogenized molecular catalysts have potential for practical use in polyalcohol-based LOHC systems.

[Display omitted] Catalysts composed of nanocluster and single-atom (SA) were extensively used to enhance electrocatalytic water splitting performance, whereas study of their photocatalytic hydrogen (H 2) evolution activity was limited. Herein, carbon nitride (CN) decorated by ruthenium (Ru) cocatalysts existed as SA + cluster, cluster + nanoparticles (NPs), and NPs were prepared by impregnation and calcination processes. The correlation between existential form, content of Ru cocatalyst and H 2 evolution rate were carefully discussed. It was found that Ru NPs were favor for water molecule adsorption, whereas Ru SAs and clusters facilitated H 2 desorption. Theoretical calculations revealed that Ru clusters + NPs cocatalyst were beneficial for H* intermediate formation. Water splitting tests found that 1.07 wt% Ru NPs + cluster modified CN showed the highest H 2 evolution rate of 13.64 mmol h−1 g−1, which was 266.4 and 1.5 times higher than those of CN and Ru NPs (2.33 wt%) decorated CN, respectively. This work deeply reveals the influences of existential form of Ru cocatalysts on photocatalytic water splitting of CN, and provides thought in designing new cocatalysts to largely enhance H 2 evolution. [ABSTRACT FROM AUTHOR]