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Carbon monoxide (CO) has been regarded as a "silent killer" for its toxicity toward biological systems. However, a low concentration of endogenously produced CO has shown a number of therapeutic benefits such as anti-inflammatory, anti-proliferative, anti-apoptosis, and cytoprotective activities. Carbon monoxide-releasing molecules (CORMs) have been developed as alternatives to direct CO inhalation, which requires a specialized setting for strict dose control. CORMs are efficient CO donors, with central transition metals (such as ruthenium, iron, cobalt, and manganese) surrounded by CO as a ligand. CORMs can stably store and subsequently release their CO payload in the presence of certain triggers including solvent, light, temperature, and ligand substitution. However, CORMs require appropriate delivery strategies to improve short CO release half-life and target specificity. Herein, we highlighted the therapeutic potential of inhalation and CORMs-delivered CO. The applications of conjugate and nanocarrier systems for controlling CO release and improving therapeutic efficacy of CORMs are also described in detail. The review concludes with some of the hurdles that limit clinical translation of CORMs. Keeping in mind the tremendous potential and growing interest in CORMs, this review would be helpful for designing controlled CO release systems for clinical applications.

The unsustainable antibacterial activity of ruthenium antibacterial agents is an important factor limiting their applications. This present work attempts to prepare ruthenium (Ru) coordination polymer composites with chitosan quaternary ammonium polymers (CQ) and shikimic acid (SA) through the interaction of ionic bonds and covalent bonds by microwave-assisted high-pressure homogenization methods. The prepared CQ@Ru-SA was characterized by size distribution, zeta potential, TEM, UV-vis, FTIR, XPS and XRD analyses. The coordination structure and morphology of Bridge-CQ-NH-Ru-SA were verified. The CQ@Ru-SA was well-dispersed in both the aqueous or anhydrous states. MIC and MBC, time-killing curves, biofilm formation inhibition assay, mature biofilm disruption assay, SEM, Ca

Fischer-Tropsch synthesis was carried out with a ruthenium catalyst by using H2/D2 switching and competitive methods. The results showed that there is an inverse isotope effect during ruthenium-catalyzed Fischer-Tropsch reactions with the hydrocarbon production rate increasing when syngas was switched to D2/CO. When the ruthenium-catalyzed Fischer-Tropsch synthesis was conducted using a mixture of H2/D2/CO (1:1:1) as the syngas, the H/D ratios in hydrocarbons produced by the reaction are less than 1, indicating that the deuterium was enriched in these hydrocarbons. Also, the deuterium enrichment is a function of carbon number with more deuterium enriched in larger hydrocarbons. These results are similar to the results of cobalt and iron catalyzed Fischer-Tropsch reactions we have reported earlier. To explain these results and other experimental facts accumulated over the years about Fischer-Tropsch synthesis, we proposed the alkylidene mechanism for this important reaction, in which MCH is the monomer of this polymerization-like reaction and M=CHR is the growing chain. Based on this mechanism, we developed mathematic equations for each step of propagations to calculate the deuterium enrichment. The theoretic deuterium enrichment results calculated based on the Alkylidene mechanism are very close to the experimental results of deuterium enrichment of ruthenium-catalyzed Fischer-Tropsch reactions.

The examination of cross metathesis reactions leading to the desired product has been conducted to uncover computationally the origin of the chemo-, regio- and stereoselectivity. The comparison between the relative stabilities of all involved intermediates and products, together with the transition states, links to the probability for the respective pathway. Particularly, the respective transition states for each reaction tune the regio- and stereoselectivity because they define the energy barriers needed to be overcome to form the new olefin as final product. The broad range of studied reactions with the 2nd generation Grubbs catalysts allows concluding in detail the points to pay attention and thus helps to understand the chemo-, regio- and stereoselectivity in new olefin metathesis reactions. Here, a web-server joins all these mechanistic insights which is intended to support future predictive olefin metathesis catalysis.

Nanoscale ruthenium (Ru)-based materials are promising replacements for existing multilayered Cu interconnects in integrated circuits. However, it is not easy to apply the results of previously reported studies directly to the electrochemical damascene process because the previous studies have mainly focused on thin films by dry deposition. Here, we report the electrical resistivity and microstructure of electrodeposited Ru nanowires. We estimate that the resistivity value of a 10 nm diameter Ru nanowire to be 71.6 μΩ cm after analyzing the resistivity values of individual nanowires with various diameters. Furthermore, we investigate the electrical properties of RuxCo1-x nanowires where x is 0.04–0.99 at.% as possible replacements of the current TaN barrier structures. Over the entire composition range, the resistivity values of alloys are much lower than that of the conventional TaN. Additionally, Ru and Ru-alloy nanowires surrounded by dielectric silica are thermally stable after 450 °C heat treatment. Therefore, the nanoscale Ru and Ru-Co alloys possessing low resistivity values can be candidates for the interconnect and barrier materials, respectively.

Exploring highly efficient electrocatalysts and understanding the reaction mechanisms for hydrogen electrocatalysis, including hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER) in alkaline media are conducive to the conversion of hydrogen energy. Herein, we reported a new strategy to boost the HER/HOR performances of ruthenium (Ru) nanoparticles through nitrogen (N) modification. The obtained N-Ru/C exhibit remarkable catalytic performance, with normalized HOR exchange current density and mass activity of 0.56 mA/cm2 and 0.54 mA/μg, respectively, about 4 and 4.5 times higher than those of Ru/C, and even twofold enhancement compared to commercial Pt/C. Moreover, at the overpotential of 50 mV, the normalized HER current density of N-Ru/C is 5.5 times higher than that of Ru/C. Experimental and density functional theory (DFT) results verify the electronic regulation of Ru after N incorporation, resulting in the optimized hydrogen adsorption Gibbs free energy (ΔGH*) and hence enhancing the HOR/HER performance.

Cis-diacetonitrilo-bis(bipyridine) ruthenium(II) chloride is a recently introduced cis-platin analogue that has anti-cancer properties with lower side effects. However, the sequence dependence of its DNA damaging mechanism is unclear. Here, we present a simple, sensitive, multiplexed mix-and-read assay for ascertaining the molecular mechanism of DNA damage induced by the studied ruthenium complex (Ru-complex). The damage kinetics and sequence specificity for the Ru-complex induced DNA damage are examined by studying the induced damage in various oligonucleotide sequences by EvaGreen-DNA intercalator probe. High-through-put measurements were established using a 96-well microplate platform that allows multiple sequences to be measured simultaneously. The results show that the extent of damage increases with an increasing number of guanines, with considerable amount of damage at GA, GT and GC sites, in particular. Furthermore, the interaction of Ru-complex with DNA was confirmed using thermal analysis and MALDI-TOF-MS. Results indicate that the activated Ru-complex preferentially binds via both mono- and di-adduct formation at G and GG sites, respectively. Moreover, the developed method was successfully applied for the determination of the potency of the studied Ru-complex to induce DNA damage in K-Ras and N-Ras family of genes, one of the most common oncogenic events in cancer.

Ru-incorporated Co3O4 nanoparticles have been synthesized from self-sacrificial ZIF-67 template and utilized as efficient electrocatalysts towards oxygen reduction and evolution reactions (ORR and OER). Amongst, Ru@Co3O4-1.0 exhibited the optimum electrocatalytic behavior with an ultra-low potential gap (0.84 V) between the OER potential (1.61 V at 10 mA cm−2) and ORR half-wave potential (0.77 V). The zinc-air battery using Ru@Co3O4-1.0 as a cathode presented high specific capacity (788.1 mAh g−1) and power density (101.2 mW cm−2). Meanwhile, this battery possessed relatively lower voltage gap and higher cycling stability compared with the commercial Pt/C-based one. Ruthenium incorporation induced remarkable lattice expansion of Co3O4 and engineered more oxygen vacancies, promoting the lattice oxygen mobility from the subsurface/bulk phase onto surface. All these properties were recognized to be the crucial parameters for electrocatalytic activity improvement. This work provided a facile approach to design highly active metal oxide with broad potentiality for rechargeable metal-air batteries.

Herein, we report an efficient, environmentally friendly and stable catalyst development to hydrogen evolution from sodium borohydride hydrolysis. For this purpose, Ruthenium complex catalyst successfully fabricated via 5-Amino-2,4-dichlorophenol-3,5-ditertbutylsalisylaldimine ligand and RuCl3·H2O salt. Ru complex catalyst was identified with X-Ray Diffraction Analysis, Infrared Spectroscopy, Elemental Analysis, Transmission electron microscopy, Scanning Electron Microscope and Brunauer-Emmett-Teller Surface Area Analysis. According to the analysis results, it was confirmed that Ru complex catalyst was successfully synthesized. Ru complex was used as a catalyst in NaBH4 hydrolysis. The kinetic performance of Ru complex catalyst was evaluated at various reaction temperatures, various sodium borohydride concentration, catalyst concentration and sodium hydroxide concentration in hydrogen evolution. The apparent activation energy for the hydrolysis of sodium borohydride was determined as 25.8 kJ mol−1. With fully conversion, the promised well durability of Ru complex was achieved by the five consecutive cycles for hydrogen evolution in sodium borohydride hydrolysis The hydrogen evolution rates were 299,220 and 160,832 mL H2 gcat−1 min−1 in order of at 50 °C and 30 °C. Furthermore, the proposed mechanism of Ru complex catalyzed sodium borohydride hydrolysis was defined step by step. This study provides different insight into the rational design and utilization and catalytic effects of ruthenium complex in hydrogen evolution performance.

Summary Natural systems drive the high-energy reactions of photosynthesis with efficient and broadband energy capture. Transition-metal photocatalysts similarly convert light into chemical reactivity, and yet suffer from light-limited operation and require blue-to-UV excitation. In photosynthesis, both light capture and reactivity have been optimized by separation into distinct sites. Inspired by this modular architecture, we synthesized a biohybrid photocatalyst by covalent attachment of the photosynthetic light-harvesting protein R-phycoerythrin (RPE) to the transition-metal photocatalyst tris(2,2′-bipyridine)ruthenium(II) ([Ru(bpy)3]2+). Spectroscopic investigation found that absorbed photoenergy was efficiently funneled from RPE to [Ru(bpy)3]2+. The utility of the biohybrid photocatalyst was demonstrated via an increase in yields for a thiol-ene coupling reaction and a cysteinyl-desulfurization reaction, including recovered reactivity at red wavelengths where [Ru(bpy)3]2+ alone does not absorb.

Developing efficient and cost-effective catalysts for hydrogen evolution reaction (HER) is vital to hydrogen energy's commercial applications. In this study, N,P-doped carbon supported ruthenium (Ru) doped triruthenium tetraphosphide (Re3P4) (Ru-Re3P4/NPC) with porous nanostructure is prepared using the low-toxic melamine phosphate as the carbon and phosphorous source. The in-situ generated N,P-doped carbon layers play a pivotal role in regulating the electrocatalytic activity by avoiding the aggregation of the nanoparticles and increasing the specific surface area. Moreover, Ru doping contributes to the remarkable electrocatalytic performance of the prepared nanomaterials. Impressively, the as-synthesized Ru-Re3P4/NPC presents remarkable electrocatalytic performances toward HER with small overpotentials of 39 mV, 115 mV, and 88 mV to deliver 10 mA cm−2 in alkaline, neutral, and acidic media. Moreover, the prepared electrocatalyst can drive water-splitting with a small potential of 1.45 V@10 mA cm−2 and use sustainable energies, including solar, wind, and thermal, as electric resources. This work paves a novel and valuable way to enhance the electrocatalytic performances of metal phosphides.

A supported ruthenium catalyst (Ru/Cs+/CeO2) for ammonia synthesis is described which incorporates a large amount of a Cs+ promoter in a porous CeO2 support to enhance the electron donation effect of the alkali promoter on the ruthenium catalyst. Optimization of the Ru and Cs+ promoter contents improves the ammonia synthesis rate to more than 4 times that of the benchmark catalyst (Cs+/Ru/MgO) at 350 °C and 0.1 MPa, and the ammonia synthesis rate is stable for 100 h. Introduction of the Cs+ promoter into the support before the Ru impregnation increases the particle size of the Ru catalyst. Despite a decrease in the number of active sites, the TOF of the catalyst is more than 50 times that of Ru (2 wt%)/CeO2. CO adsorption measurements suggest an electron donating effect by the Cs+ promoter to ruthenium metal. Reaction order analysis indicates this is due to a mitigation of hydrogen poisoning.

Thiolate-bridged hetero-bimetallic complexes [Cp*M(MeCN)N2S2FeCl][PF6] (2, M = Ru; 3, M = Co, Cp* = η5-C5Me5, N2S2 = N,N'-dimethyl-3,6-diazanonane-1,8-dithiolate) were prepared by self-assembly of dimer [N2S2Fe]2 with mononuclear precursor [Cp*Ru(MeCN)3][PF6] or [Cp*Co(MeCN)3][PF6]2 in the presence of CHCl3 as a chloride donor. Complexes 2 and 3 exhibit obviously different redox behaviors investigated by cyclic voltammetry and spin density distributions supported by DFT calculations. Notably, iron-cobalt complex 3 possesses versatile reactivities that cannot be achieved for complex 2. In the presence of CoCp2, complex 3 can undergo one-electron reduction to generate a stable formally CoIIFeII complex [Cp*CoN2S2FeCl] (4). Besides, the terminal chloride on the iron center in 3 can be removed by dehalogenation agent AgPF6 or exchanged with azide to afford the corresponding complexes [Cp*Co(MeCN)N2S2Fe(MeCN)][PF6]2 (5) and [Cp*Co(MeCN)N2S2Fe(N3)][PF6] (6). In addition, complexes 2, 3 and 4 show distinct catalytic reactivity toward the disproportionation of hydrazine into ammonia. These results may be helpful to understand the vital role of the heterometal in some catalytic transformations promoted by heteromultinuclear complexes.

By combining capture and catalytic conversion of carbon dioxide to chemicals and fuels in a single process operation, one can potentially increase the efficiency and feasibility of waste carbon utilization. We report here results for CO2 capture using amines supported on high-surface-area silicas, including fumed silica and mesoporous SBA-15, in tandem with a homogeneous ruthenium hydrogenation catalyst in a batch reactor system, and compare these with previous reports for two- and three-phase versions of capture + hydrogenation systems. While diamine- and polyamine-functionalized solid capture agents led to higher methanol productivities than homogeneous amine and homogeneous catalyst combinations, turnover of the amine capture sites is a significant limitation that has not been previously recognized. These results demonstrate that tandem catalysis in these systems has not yet been achieved, despite previous claims to the contrary.

Catalytic ammonia (NH3) decomposition has been identified as a COx-free, sustainable hydrogen production method for fuel cell applications. In this study, the performance of plasma–catalyst-based NH3 decomposition over ruthenium (Ru/Al2O3) and soda glass (SiO2) catalytic materials at atmospheric pressure and ambient temperature was investigated. NH3 decomposition reactions were conducted in a dielectric barrier discharge plasma plate-type reactor. NH3 was fed into the plate catalytic microreactor at flow rates of 0.1–1 L/min and plasma voltages of 12–18 kV. Compared to plasma NH3 decomposition without a catalyst, plasma–catalyst-based NH3 decomposition showed a significant enhancement of the hydrogen production rate and energy efficiency. Furthermore, the hydrogen concentration results obtained over the Ru/Al2O3 catalyst were higher than those over the SiO2 catalyst because Ru/Al2O3 possesses good electronic properties and exhibits high sensitivity to NH3 decomposition. In addition, the resulting plasma heat enhanced the activation of the catalytic material, subsequently leading to an increase in the hydrogen production rate from NH3. The maximum conversion rates were 85.65% and 84.39% for Ru/Al2O3 and SiO2, respectively. Moreover, the energy efficiency of NH3 decomposition over the Ru-based catalyst material was higher than that over the SiO2 material. The presence of the catalyst active sites and plasma enhanced the mean electron energy, which could enhance the dissociation of NH3. It can be concluded that the SiO2 material can be utilised as a catalyst and that its combination with plasma accelerates the decomposition process of NH3 and incurs a lower cost compared to Ru materials.

A series of Ni2-xRuxP/SiO2 catalysts spanning the full composition space (0 ≤ x ≤ 2) were prepared from hypophosphite-based precursors (P/M = 0.72, M = Ni + Ru). The Ni2-xRuxP/SiO2 catalysts having Ni-rich compositions (x

Gamma-valerolactone (GVL) is a versatile building block compound with wide applications and it can be obtained from biomass-derived chemical levulinic acid (LA). In this study, graphite carbon nitride (g-C3N4) were prepared from two different precursors (urea and melamine) and used as the support to anchor ruthenium (Ru) nanoparticle (Ru/g-C3N4) for catalytic transfer hydrogenation of LA to GVL. The resulting catalyst prepared from urea precursor (Ru/UCN) showed 100% LA conversion and nearly theoretic GVL yield of 99.8% under mild condition. Detailed characterizations of the Ru/g-C3N4 suggested that Ru showed different interactions with the g-C3N4 supports from two different precursors. Ru nanoparticles exhibited smaller size and better dispersion on the g-C3N4 support from urea (UCN) than that from melamine (MCN). The XPS result indicated that more electron rich Ru0 species on the Ru/UCN catalyst also contributed to the higher catalytic activity of the Ru/UCN. Furthermore, the Ru/UCN catalyst was demonstrated high stability in acidic reaction medium and remained highly reactive after recycled for 5 times.

The work aimed at the mechanistic investigation of the catalytic hydrogenation of cyclohexene by a newly synthesized ruthenium(III) Schiff base complex, [RuLCl(H2O)], where L represents tetradentate N2O2 naphthaldiimine. Several physicochemical methods were used to characterize the target complex. Furthermore, it was observed that the catalytic activity relies mainly on solvent composition. On the other hand, the density functional theory (DFT) was applied to explore the mechanistic story of the catalytic reaction. The findings showed that the complex has two stable isomers (trans and cis), which serve as platforms for the destination toward the hydrogenation journey through the in-situ generation of the active catalysts. Accordingly, one can imagine them as robust and weak machines for cyclohexane production in the reaction vessel. Interestingly, the experimental and the theoretical total activation energies are so comparable which supports the validity of the mechanistic insights.

Many researches have shown that phosphorus doping can affect the photocatalytic activity, mainly because the incorporation of P atoms significantly alters the electronic, surface chemical, and properties of different semiconductors. However, excessive phosphorous doping will form the accumulation and recombination center of photo-generated charge carrier, thereby limiting the activity of photocatalytic reactions. In this work, we successfully prepared excessive P-doping g-C3N4 with ruthenium phosphide nanoparticles (RuxP/PCN), which had excellent performance of hydrogen evolution (1.94 mmol g−1 h−1). Specifically, C was replaced by P in the melon units of PCN and positive charge center (P+) was introduced, reinforcing the chemical connection between PCN and RuxP. In fact, excessive P+ centers became the traps and stacking centers of photo-generated carriers. However, due to the introduction of RuxP NPs, the accumulated charges in the P+ centers through the chemical bridges between PCN and RuxP NPs migrated to surface and then separated on RuxP NPs. Our research illustrates the mechanism of the accumulated charges caused by excessive phosphorus doping migrate to the surface and separate on phosphides, which can prolong the lifetime of photo-generated carriers. This result promoted the significant increase of photocatalytic hydrogen production activity. Our research clarifies the mechanism of excessive phosphorus doping and phosphides act on this photocatalytic system, which will provide a new way to design a photocatalytic system with higher HER performance.

The hydrogen evolution reaction (HER) is a key step for producing hydrogen by water electrolysis, and an economical, facile and environment friendly method of fabricating catalysts for HER is urgent and essential. In this work, we design a high efficient and stable HER catalyst though a simple adsorption and pyrolysis method. The fabricated catalyst presents ruthenium (Ru) quantum dots (QDs) uniformly distributes on the carbon nanofibers (CNF) with a three dimensional (3D) networks structure (Ru@CNF). By means of quantum size effect of Ru QDs and the 3D networks structure of the carbon nanofibers, the former is beneficial to provide more catalytic active sites and the latter is in favour of electron transport. The sample Ru@CNF exhibits a low overpotential of 20 mV at a current density of 10 mA cm−2 and Tafel slope of 31 mV dec−1 in 1 M KOH, which is better than that of Pt/C (28 mV and 36 mV dec−1), and most of reported Ru-based and transition metal catalysts. Furthermore, it exhibits robust stability when testing at an overpotential of 75 mV for 24 h. Therefore, this work provides a low-cost, simple and feasible method for fabricating HER catalyst, which possesses commercial application prospect in the field of producing hydrogen by water electrolysis.

Industrial hydrogenation catalysts must be not only selective and active but also resistant to feedstock impurities, including water. We report the strategy of preparing catalytic core-shell nanoreactors based on hydrophobized aluminosilicate nanotubes loaded with ruthenium. The modification of halloysite with alkyltriethoxysilanes enhances hydrophobicity of the clay nanotubes (water contact angle up to 122°) and enables their selective loading with 4-nm ruthenium particles. Such a core-shell tubular nanoreactors provide shielding of active sites from deactivation by admixed water and prevent metal leaching. Produced mesoscale catalysts were active in the hydrogenation of aromatics both in organic and aqueous media at 80 °C and a hydrogen pressure of 3 MPa. Benzene hydrogenation in the biphasic system with water resulted in a complete conversion with 100 % selectivity to cyclohexane over halloysite modified by C18-triethoxysilane supported ruthenium catalyst with turnover frequency (TOF) of 4371 h−1. This catalytic system remained stable after ten cycles of benzene hydrogenation, providing 98 % conversion. The demonstrated synthetic strategy is promising for the design of industrial catalysts for the hydroprocessing water-containing organic feedstock and may be upscaled due to the abundant availability of halloysite clay nanotubes.

Metal-free covalent organic frameworks (COFs) as visible-light active and recyclable photocatalysts afford an eco-friendly and sustainable option to classical photosensitizers, which usually require noble metals (iridium, ruthenium, rhodium, etc.) to produce photocatalytic activity. Most classical small molecule photosensitizers have poor recyclability with certain limitations. As a result, it is of great significance to develop a metal-free and easily recyclable COF photocatalyst. In this study, we designed and synthesized a new type of COF photocatalyst (BTT-TPA-COF) in which benzotrithiophene and triphenylamine units are alternately connected. It has high specific surface area, permanent porosity and good stability. In addition, this design strategy can effectively adjust the band gap, energy level and photoelectric performance of BTT-TPA-COF. As a metal-free photocatalyst, BTT-TPA-COF exhibits high-efficiency photocatalytic activity, excellent substrate tolerance and excellent recyclability for the synthesis of 2-arylbenzimidazole compounds. This research not only puts forward a design strategy for high-efficiency photocatalysts, but also broadens the application range of COF materials in photocatalytic organic reactions.

2-(N-alkylamino)pyrimidines are important heterocycles widely found in various pharmaceutically important drugs. Here, we have disclosed a new cooperative ruthenium complex catalyzed tandem multicomponent synthesis of 2-(N-alkylamino)pyrimidines directly from guanidine salt and alcohols. The reactions proceeded through the dehydrogenation of alcohols, followed by C C coupling and sequential C N coupling with guanidine and primary alcohol, with the elimination of three equivalents of hydrogen gas. In this work, application of both the acceptorless dehydrogenative coupling (ADC) and borrowing hydrogen (BH) strategies were accomplished in a single reaction. This catalytic method tolerated a wide range of substrates. The viability of the current method was demonstrated by preparative scale synthesis of a few products. A plausible catalytic cycle was proposed based on various control experiments, mechanistic studies and DFT calculations. Remarkably, 42 new 2-(N-alkylamino)pyrimidines were synthesized following this catalytic protocol.

The hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) by using water as solvent is a crucial process in the production of fine chemicals from biomass. An ultrathin carbon layer coating CoRu bimetallic catalyst supported on silica (CoRu@C/SiO2) is prepared by using tannis-ligated cobalt-ruthenium complex on silica as precursors, and applied for catalyzed synthesis of GVL from LA. Because of the synergistic effect between cobalt and ruthenium, the addition of small amounts of Ru to Co catalysts can increase the catalytic activity in the aqueous hydrogenation of LA. The ultrathin carbon layer covered on the CoRu bimetallic catalyst can greatly reduce the leaching of active metals. The CoRu@C/SiO2 catalyst achieves high stability and is reused up to 5 runs without significant loss of performance in aqueous hydrogenation of levulinic acid.

Ammonia synthesis catalysts with high activity under mild reaction conditions for use in synthetic chemical processes powered by renewable energy are needed. Here, we investigated the physicochemical properties and ammonia synthesis activity of lanthanoid oxide–supported Ru catalysts. The basicity of the Ru/lanthanoid oxide catalysts, as estimated by CO2 temperature-programmed desorption, was higher than that of Ru/MgO, a representative catalyst with high ammonia synthesis activity, and a positive relationship was observed between basicity and turnover frequency. The turnover frequency of Ru/Pr2O3 and Ru/La2O3 (both 0.24 s−1) was eight times that of Ru/MgO (0.03 s−1). A kinetic analysis revealed that hydrogen poisoning, which is a typical drawback of oxide-supported Ru catalysts, was markedly retarded in the Ru/lanthanoid oxide catalysts. As a result, the ammonia synthesis rate of the Ru/Pr2O3 catalyst increased with increasing reaction pressure, reaching 49 mmol g−1 h−1 at 400 °C and 1.0 MPa, which was 12 times that of Ru/MgO under the same conditions.

The device performance of the dye-sensitized solar cells (DSSCs) mainly depends on the sensitizers. Ruthenium sensitizers have played a vital role in the DSSCs to improve power conversion efficiency. However, the absorbance spectra of most Ru-sensitizers limited up to 600 nm, which maybe prohibiting further improvement of short-circuit current density (Jsc). To address this problem, TER-HDT was designed and synthesized by incorporating hexyl dithiafulvalene (HDT)-substituted bipyridine as an ancillary ligand and [2,2′:6′,2′'-terpyridine]-4,4′,4′'-tricarboxylic acid as anchoring ligand together. The synthesized TER-HDT was systematically studied and characterized by spectroscopic (proton NMR, Mass analysis), optical (UV-absorbance and photoluminescence), electrochemical and theoretical techniques. The novel sensitizer TER-HDT absorption tailed up to 900 nm, which originated from the enhanced intermolecular charge transfer in conjunction with efficient intra and intermolecular interactions. The HOMO and LUMO energy levels TER-HDT are suitable for electron injection and regeneration which may help to achieve high efficiency.

Water oxidation is the bottleneck of artificial photosynthesis. Since the first ruthenium-based molecular water oxidation catalyst, the blue dimer, was reported by Meyer's group in 1982, catalysts based on transition metals have been widely employed to explore the mechanism of water oxidation. Because the oxidation of water requires harsh oxidative conditions, the stability of transition complexes under the relevant catalytic conditions has always been a challenge. In this work, we report the redox properties of a CuIII complex (TAML-CuIII) with a redox-active macrocyclic ligand (TAML) and its reactivity toward catalytic water oxidation. TAML-CuIII displayed a completely different electrochemical behavior from that of the TAML-CoIII complex previously reported by our group. TAML-CuIII can only be oxidized by one-electron oxidation of the ligand to form TAML•+-CuIII and cannot achieve water activation through the ligand-centered proton-coupled electron transfer that takes place in the case of TAML-CoIII. The generated TAML•+-CuIII intermediate can undergo further oxidation and ligand hydrolysis with the assistance of borate anions, triggering the formation of a heterogeneous B/CuOx nanocatalyst. Therefore, the choice of the buffer solution has a significant influence on the electrochemical behavior and stability of molecular water oxidation catalysts.

Taking the advantage of multifunctional characteristics of chitosan (CS), we have developed new scaffolds (imidazolium-vanillyl-chitosan Schiff bases (IVCSSBs)) for supporting Pd(II) and Ru(II) ions in catalyzing Suzuki coupling reactions. The structures of new materials were described based on their elemental, spectral, thermal, and microscopic analysis. The strong interactions between the binding sites of IVCSSB ligand (OH, H-C=N, and OCH3 groups) and Pd(II) ions resulted in the formation of an excellent heterogeneous catalyst (Pd(II)IVCSSB1) with amazing catalytic activity (up to 99%) and highly stable in the reaction medium. The reusability experiments for Pd(II)IVCSSB1 revealed that there is no appreciable decrease in its catalytic activity even after five consecutive operation runs. Furthermore, this heterogeneous catalyst showed an excellent selectivity toward the cross-coupling reaction where no homo-coupling byproducts were observed in the 1H NMR spectra of the obtained products. Consequently, the present ionic catalytic system may open a new window for a novel generation of ionic bio-based catalysts for organic transformations.

Summary The isomerization of terminal alkenes is an important and atom-economical process that accesses otherwise difficult-to-prepare internal alkenes via a precious metal (e.g., ruthenium and iridium)-catalyzed isomerization reaction. Using earth-abundant metal-based catalysts in this transformation, however, has only recently gained prominence and their selectivity and activity are not yet comparable with their precious metal counterparts. Here, we report that the anionic iron hydride complex [(PCNHCP)Fe(H)N2]− (4) is highly active for the selective one-bond isomerization of terminal alkenes. Isomerization occurs at room temperature and provides the internal alkenes with good regio- and stereoselectivity (E/Z ≥ 10:1). The maximum turn-over number (TON) of 4 is ≥160,000, and is better than the most active precious metal catalysts. Experimental and computational studies suggest an alkyl-type mechanism for alkene isomerization, where two-state reactivity is responsible for the exceptional reactivity of complex 4.

The effects of ruthenium content on Ti/RuO2-Sb2O5-SnO2 anodes are investigated in terms of catalytic activity and stability for oxygen evolution. The best electrochemical stability appears at nominal Ru content around 30%, giving average accelerated lives of 419 and 165 h at 25 and 70 °C, respectively, under the current density of 500 mA cm−2 in 3 M H2SO4 solution. These values are respectively ~8 and >22 times longer than any types of RuO2-based electrodes reported previously. The electrocatalytic activity of Ti/RuO2-Sb2O5-SnO2 anodes is found to increase with nominal Ru content approaching 75%. The physicochemical and electrochemical analyses reveal that the homogeneous intermixture of RuO2, SnO2 and Sb2O5 with a smooth and compact surface decreases the dissolution rate of RuO2, leading to a significant improvement on the electrode service life. Despite the numerous pores and cracks found in the coating, Ti/RuO2-Sb2O5-SnO2 anode with a nominal Ru content of 75% exhibits better electrocatalytic performance for O2 evolution, which is attributed to more active RuO2 sites exposed to electrolyte. Therefore, the existence of the optimal Ru content for Ti/RuO2-Sb2O5-SnO2 is the balanced effect between electrochemical stability and activity for O2 evolution, as well as cost for specific applications.

Summary C–H functionalization reactions constitute a key pillar in streamlining synthesis methods. In this context, the use of visible light to mediate metal-catalyzed C–H functionalization reactions is currently emerging as an important strategy to facilitate such transformations and enables mild C–H functionalization reactions at ambient conditions without the need for external photosensitizers or reactive reagents. Herein, we report on a photochemical approach that allows for C(sp3)–H functionalization reactions using simple [Ru(cymene)Cl2]2 and a phosphoric acid diester as catalysts. This strategy enables formal C(sp3)–C(sp3) coupling reactions to access valuable, sterically demanding amines and expands photochemical C–H functionalization reactions toward reaction pathways exclusive to photochemistry. Detailed mechanistic experiments and density functional theory calculations suggest the formation of a cyclometalated ruthenium complex that is stabilized by the phosphoric acid diester anion and serves as a catalyst for C–H functionalization reactions and single-electron transfer to access C–H functionalization reactions via a deprotonation-radical addition mechanism.

A facile eco-friendly heterogeneous catalytic system has been developed for amide synthesis that further utilized in pharmaceutical and organic chemistry. The Ru/MnO2 catalyst has shown outstanding and unprecedented activity for a wide range of aliphatic and benzylic nitriles in green solvent water at 60 °C. The system has also exhibited a remarkable tolerance for selective hydration of heteroatom (e.g. nitrogen, oxygen and sulphur atoms) containing nitriles. Pharmaceutically important nicotinamides and pyrazinamide has been synthesized by hydration of the heteroatomic nitriles with appreciable yields and selectivities. Moreover, the Ru/MnO2 catalyst has employed water as a benign solvent, with more than 30,000 TONs and reusability five times after isolation from the reaction mixture by centrifugation and easy workup that established a path for green environmental and technologically acceptable protocol.

The present study focused on the increasing of hydrogen evolution through hydrolysis of potassium borohydride in the presence of Ruthenium complex catalyst. It is the first time to use the Ru-Imine complex catalyst in KBH4 hydrolysis reaction to hydrogen evolution. The new Ru complex was synthesized from the tetradentate Imine ligand namely 4,4′-methylenebis (2,6-diethyl)aniline-3,5-di-tert-butylsalisylaldimine and Ru salt under the inert atmosphere. Ru-Imine complex was fully characterized by Elemental Analysis, Infrared Spectroscopy, Scanning Electron Microscope, X-Ray Diffraction Analysis, Brunauer-Emmett-Teller Surface Area Analysis and Transmission Electron Microscopy. By the synthesized Ru-Imine complex catalyst, the potassium borohydride hydrolysis reaction resulted in a lower energy barrier with 20,826 kJ/mol activation energy (Ea) for nth order kinetic model and 18,045 kJ/mol for Langmuir-Hinshelwood (L-H) kinetic model. According to the results Ru-complex was highly active and stable catalyst in KBH4 hydrolysis reaction to hydrogen evolution with 45,466 mL H2/gcat.min and 76,815 mL H2/gcat.min hydrogen generation rates at 30 °C and 50 °C respectively. Moreover Ru-Imine complex catalyst displayed 100% stability even at fifth recycle.

Monoclinic BiVO4 (BVO) properties favor its use as the main absorber in photoanodes applied for photoelectrochemical water splitting. However, hindrances as the high rate of recombination of the electrons and holes photogenerated and as the poor charge carrier transport limit its direct, practical use. Doping, building a heterojunction with other semiconductors and decorating the surface with catalysts like cobalt phosphate and ruthenium oxide are among the many existing approaches to improve BVO performance. The deposition of catalyst or cocatalyst normally involve the use of potentially hazardous techniques as chemical vapor deposition (CVD). In this work, we present a simple route for enhancing photoelectrochemical results in BVO samples. The decoration with metallic ruthenium is performed via magnetron sputtering DC, a reliable, inexpensive and safe-to-use physical deposition technique, followed by a thermal treatment in air within a muffle furnace for 6 h at 400 °C. A gain of about 45% in the photocurrent at 1.23 V vs reversible hydrogen electrode (RHE) and in the overall spectrum area in comparison with pristine BVO samples was registered by cyclic voltammetry measurements in a 0.5 M phosphate buffer solution under full spectrum illumination from a 100 W Xenon lamp. The morphological and chemical modifications that resulted in such photocurrent rise were characterized using Scanning Electron Microscopy (SEM), Rutherford Backscattering Spectrometry (RBS) and X-ray Photogenerated Spectroscopy (XPS).

Ammonia borane (AB) hydrolysis is a comparative strategy for developing the sustainable hydrogen economy. Considering the hydrolysis cannot occur kinetically at low temperature, a suitable catalyst is indispensable. In this work, the dispersed ruthenium nanoparticles are stabilized on hexagonal boron nitride (h-BN) via an adsorption-in situ reduction procedure. Various characterization techniques are adopted for elucidating the structure-performance relationship of the obtained catalysts for the hydrolytic dehydrogenation of AB. In the presence of the resultant Ru/h-BN catalysts, the corresponding turnover frequency (1177.5 min−1) in alkaline solution at 303 K and the apparent activation energy (24.1 kJ mol−1) are superior to most literature previously reported. Our work provides a facile fabrication method for metal-based catalysts, which are highly promising in chemical storage material hydrolysis.

We report the synthesis of magnetically isolable ruthenium(0), rhodium(0), and palladium(0) nanoparticles, supported on carbon-coated magnetic iron particles, and their employment as catalysts in hydrolysis of ammonia borane. Carbon-coated iron (C–Fe) particles are obtained by co-processing of iron powders with methane in a radio frequency thermal plasma reactor. The impregnation of ruthenium(III), rhodium(III) and palladium(II) ions on the carbon-coated iron particles followed by aqueous solution of sodium borohydride leads to the formation of respective metal(0) nanoparticles supported on carbon-coated iron, M0/C–Fe NP (M = Ru, Rh, and Pd) at room temperature. M0/C–Fe NPs are characterized using the ICP-OES, XPS, TEM, and EDX techniques and tested as catalysts for hydrolysis of ammonia borane at 298 K. The results reveal that Rh0/C–Fe, Ru0/C–Fe, Pd0/C–Fe catalysts provide turnover frequency of 83, 93, and 29 min−1, respectively, in this industrially important reaction. More importantly, these magnetically separable metal(0) nanoparticles show very high reusability with no noticeable activity loss in subsequent runs of hydrolysis evolving 3.0 equivalent H2 per mole of ammonia borane.

Polypyridyl coordinating ligands are common in metal complexes used in medicinal inorganic chemistry. These ligands possess intrinsic cytotoxicity, but detailed data on this phenomenon is sparse, and cytotoxicity values vary widely and are often irreproducible. In order to provide new insights into the biological effects of bipyridyl type ligands and structurally related metal-binding systems, reports of free ligand cytotoxicity were reviewed. The cytotoxicity of 25 derivatives of 2,2′-bipyridine and 1,10-phenanthroline demonstrates that there is no correlation between IC(50) values and ligand properties such as pKa, log D, polarizability volume, and electron density, as indicated by NMR shifts. As a result of these observations, as well as the various reported mechanisms of action of polypyridyl ligands, we offer the hypothesis that biological effects are governed by the availability of and affinity for specific metal ions within the experimental model.

In this manuscript, ruthenium (Ru) nanoparticles functionalized with nitrene ligands through the ruthenium-nitrene (Ru N) π bonds are explored. By synthesizing the nitrene ligands with and without 15N-labelling, Ru N π bonds on Ru nanoparticles are evidenced by experimental and theoretically calculated FTIR spectra. The coordination of nitrene ligands on Ru nanoparticles surface, the interfacial charge delocalization and the impact of nitrene ligands on the catalytic performance of Ru nanoparticles are further characterized by magic-angle spinning solid-state carbon nuclear magnetic resonance spectroscopy (13C NMR) of 13CO-adsorbed Ru nanoparticles, photoluminescence and the hydrogenation of styrene.

A Ru(II)-catalyzed para-difluoroalkylation of aromatic aldehydes and ketones with a transient directing group has been developed. It utilizes less expensive ruthenium catalysts and allows facile access to challenging difluoroalkylated aldehydes. The mechanism studies suggest that the distinct coordination mode of ruthenium complex with imine moieties is responsible for para-selectivity.

Ion exchanged Ru/ZSM-5 and Ru/BEA catalysts, prepared by replacing the extra framework NH4+ cations in zeolites with Ru3+ ions, are employed for the hydrodeoxygenation of guaiacol. The performance results indicate ion-exchanged Ru zeolites, with extremely low Ru contents (~0.2 wt%), possess a high intrinsic HDO activity compared to the catalysts prepared by the incipient wetness impregnation method. On the basis of TEM, FTIR, XPS and TPD analysis, the NH4+ ions in zeolite were substituted by Ru species, with metal particles entered the zeolite cages and finely dispersed on the support. These ion-exchanged Ru particles exhibit a strong electronic interaction with oxygen atoms of zeolite framework with a mixed Ru(0)-Ru(III) species observed in the reduced samples. In contrast, only Ru0 was detected in the reduced impregnated Ru/ZSM-5. The partial-reduced Ru species over the ion-exchanged Ru/ZSM-5 catalyst shows a high H2 adsorption activity facilitating the hydrogenation of guaiacol to the saturated products (such as 2-methoxycyclohexanol). In addition, ion-exchanged Ru-ZSM-5 and Ru-BEA catalysts present a similar normalized cyclohexane formation rate (based on the concentration of acid sites), suggesting the acid sites play a pivotal role in the deoxygenation of 2-methoxycyclohexanol to cyclohexane.

The development of new materials based on abundant elements, reduced toxicity is today crucial for the next generation of energy device. Titanium-doped hydroxyapatite (TiHA) was tested for the first time as photoanode material for Dye – Sensitized Solar Cells (DSSCs). The chemical composition and energy structure of TiHA powders with increasing titanium content (5 wt%, 10 wt% and 15 wt%) were extensively characterized by surface electron spectroscopies, XPS and UPS. Their compatibility with conventional ruthenium-based dyes molecules was also assessed, producing considerable uptake. TiHA films were produced by screen-printing technique and XRD analyses confirm the presence of apatitic structure. The film properties were completely determined by optical, morphological (FE–SEM) and functional characterizations. Finally, TiHA-based DSSCs were assembled and their photovoltaic performance were assessed. The best efficiency, equal to 0.14%, was obtained for the TiHA containing 15 wt% of titanium. These results open the path for the possible application of doped hydroxyapatite as novel materials for energy conversion systems.

A ruthenium complex bearing a functional 2,2′-bibenzimidazole ligand [(p-cymene)Ru(BiBzImH2)Cl][Cl] was designed, synthesized and found to be a general and highly efficient catalyst for the synthesis of quinolines via acceptorless dehydrogenative coupling of o-aminobenzyl alcohols with ketones in the presence of carbonate salt. It was confirmed that NH units in the ligand are crucial for catalytic activity. The application of this catalytic system for the scale-gram synthesis of biologically active molecular was also undertaken. Notably, this research exhibits new potential of metal–ligand bifuctional catalysts for acceptorless dehydrogenative reactions.

Developing high-efficient and low-cost photocatalysts is of great significance yet challenging for photocatalytic hydrogen evolution. Herein, we report a 2D/2D Ru-modulated CoP nanosheets (Ru-CoP-x, where x refers the Ru-to-Co molar ratio)/g-C3N4 nanosheets (GCN NSs) ternary hybrid as a photocatalyst for hydrogen evolution under visible light. The optimal photocatalyst 25% Ru-CoP-1:8/GCN NSs exhibits an excellent hydrogen evolution rate of 1172.5 µmol g−1 h−1 under visible light with a high apparent quantum efficiency (AQE) of 3.49% at 420 nm, which is close to Pt/g-C3N4 photocatalytic system and higher than most reported transition metal phosphides (TMP)/g-C3N4 photocatalytic system. Experimental results indicate that the higher photocatalytic hydrogen evolution performance can be mainly attributed to the binary Ru-CoP-x co-catalyst with efficient charge separation and promoted surface water reduction kinetics, and the 2D/2D self-assembly structure with strong interface Schottky effect and short charge transport distance. This study provides a new approach to develop cost-effective Pt-alternative co-catalysts for photocatalytic hydrogen evolution by incorporating a small amount of ruthenium into the transition metal phosphides.

Herein, an induced self-enhanced electrochemiluminescence (ECL) sensor with superior ECL performances was simply fabricated by just dropping the ECL reagent (tris(4,4′-dicarboxylicacid-2,2′-bipyridyl) ruthenium (II) dichloride, Ru(dcbpy)3Cl2) and coreactant (nitrogen-doped carbon quantum dots, NCQDs) pair onto the surface of glassy carbon electrode. In this strategy, based on the carboxyl (–COOH) groups in Ru(dcbpy)32+ and oxygen, nitrogen-containing groups on NCQDs surface, an intermolecular hydrogen bonds-induced self-enhanced ECL composite was generated in the solid contact layer for the first time. Since Ru(dcbpy)32+ and NCQDs were co-existing in the same composite, the electron-transfer distance between them was shortened and the energy loss was decreased, thereby higher ECL efficiency was acquired. This working process greatly avoided the introduction of signal amplifier and simplified the experimental operation. On this basis, 17β-estradiol (E2) was selected as a target model to fabricate a self-enhanced ECL aptamer sensor for the investigation of its analytical performances. Resultantly, excellent detection properties of E2, including wider linear range of 1.0 × 10-14 − 1.0 × 10-6 mol L-1 and lower detection limit of 1.0 × 10-15 mol L-1 with superior selectivity, were successfully achieved. Finally, E2 spiked into milk powder was quantified to assess the practicability of this sensor. Prospectively, this strategy could be extensively applied for other analytes determination by adjusting the corresponding target aptamers.

Developing high-efficiency and low-cost catalysts for hydrogen evolution from hydrolysis of ammonia borane (AB) is significant and critical for the exploitation and utilization of hydrogen energy. Herein, the in-situ fabrication of well-dispersed and small bimetallic RuNi alloy nanoparticles (NPs) with tuned compositions and concomitant hydrolysis of AB are successfully achieved by using graphitic carbon nitride (g-C3N4) as a NP support without additional stabilizing ligands. The optimized Ru1Ni7.5/g-C3N4 catalyst exhibits an excellent catalytic activity with a high turnover frequency of 901 min−1 and an activation energy of 28.46 kJ mol−1 without any base additives, overtaking the activities of many previously reported catalysts for AB hydrolysis. The kinetic studies indicate that the AB hydrolysis over Ru1Ni7.5/g-C3N4 is first-order and zero-order reactions with respect to the catalyst and AB concentrations, respectively. Ru1Ni7.5/g-C3N4 has a good recyclability with 46% of the initial catalytic activity retained even after five runs. The high performance of Ru1Ni7.5/g-C3N4 should be assigned to the small-sized alloy NPs with abundant accessible active sites and the synergistic effect between the composition-tuned Ru–Ni bimetals. This work highlights a potentially powerful and simple strategy for preparing highly active bimetallic alloy catalysts for AB hydrolysis to generate hydrogen.

The reaction of CO2 hydrogenation is of high environmental interest since it allows for the transformation of the logistically challenging H2, gained from renewable sources, to the much more manageable hydrocarbons. Ruthenium is a catalyst widely used to produce methane from CO2. In this study we present an example of how Electrochemical Promotion of Catalysis (EPOC) can elucidate the role of solid electrolytes (YSZ, BZY) supporting Ru porous films or nanoparticles. It is found that the sign of the charge (-/+) of the current-conducting species of the electrolyte has a profound effect on the selectivity of Ru during CO2 hydrogenation. Using this insight, we have developed and tested a new supported Ru-Co catalyst for the production of higher hydrocarbons.

It is still a challenge to develop the high-efficiency noble metal-based electrocatalyst with good dispersion and durability for hydrogen evolution reaction (HER) in wide pH range. Herein, we have successfully synthesized a nitrogen-doped carbon (NC) coated ultrafine ruthenium phosphides (RuP2) nanoparticles catalyst with a facile method. With the help of ethylene diamine tetraacetic acid (EDTA), the uniform RuP2 nanoparticles with ultrafine size of about 3 nm are well dispersed on the surface of the NC. The directed coordination between EDTA and Ru ion may be responsible for the excellent structure. Benefiting from the superior electrical conductivity of NC carrier and the reduced resistance of electrons to the active site, the prepared ultrafine RuP2@NC demonstrates the obviously enhanced electrocatalytic activity for HER, which results in higher current density and lower overpotentials (99, 98 and 196 mV to reach 10 mA cm−2 in 0.5 M H2SO4, 1 M KOH and 1 M PBS, respectively). The stability is also very good due to the close integration between ultrafine RuP2 and NC. This work provides a new view to rationally design and synthesize the highly effective, stable and great dispersion of phosphide-based electrocatalysts for HER.

Fuel cells (FC) have been developed for automobiles and stationary power units. In addition to a power generator function, we propose a new application of hydrogen isotope separation. In this paper, deuterium (D) separation is investigated by two types of AFCs with platinum (Pt) or ruthenium (Ru) anode catalysts. The characteristics of the AFCs are evaluated by pure protium (H) or deuterium gas separately. In the case of Pt catalyst, the cell current/voltage curves show similar results for both gases. But a remarkable decrease in the voltage value is observed probably due to the mass transportation (diffusion) limitation at Ru catalyst. The limitation effect was larger for D2 than H2 gas. The AC impedance measurements supports the slow reaction rate of D2 gas on Ru catalyst. The separation experiments are verified with hydrogen gas mixed with 1 at% D. The D is diluted in the unreacted gas discharged from AFC with Pt catalyst, but it is concentrated with Ru one. The inverse response may be attributed to the elementary process of the hydrogen oxidation reaction and the difference in the adsorption energy of gas and water molecules on the catalyst surface. © 2020 Hydrogen Energy Publications LLC