RuO4 Research Articles

Investigation of short-term chemical changes in stable ruthenium added to soil by using X-ray absorption fine-structure analysis.

Radioactive ruthenium may be accidentally released from spent nuclear fuel reprocessing plants to the surrounding environment. However, research on the chemical behavior of radioactive Ru in the environment is limited, and the complex chemical properties of this element complicate the application of extraction methods for the analyses of its chemical forms. To obtain basic information regarding the outcome of radioactive Ru in the environment, we investigated the changes in the form of stable Ru added to soil through X-ray absorption fine-structure (XAFS) analysis. This study uses ruthenium tetroxide (RuO4), ruthenium dioxide (RuO2), ruthenium nitrosyl nitrate (Ru(NO)(NO3)3) and ruthenium chloride (RuCl3) as test sources. These are added to ultrapure water, soil solution or fresh soil samples, which are analyzed using XAFS immediately or 5 days after Ru addition. The Ru K-edge X-ray absorption near edge structure spectra acquired immediately after Ru addition differed with respect to the source. The XAFS results suggest that RuO4 immediately changes to tetravalent form after deposition from air to soil. For RuCl3, the ionic structure in the vicinity of Ru is affected by the soil even if the valence does not change immediately. By contrast, RuO2 and Ru(NO)(NO3)3 are highly stable in soil. The results show that the chemical forms of RuO2 and Ru(NO)(NO3)3 added to the soil solution and soil are retained for 5 days, whereas those of RuCl3 and RuO4 are affected by the soil solution and soil within a short period. These results emphasize the need to focus on the chemical form of Ru deposits and the form change after Ru addition when investigating the environmental fate of radioactive Ru.

Release Behavior of Gaseous Ruthenium Tetroxide During Heating of High-Level Liquid Waste Simulant During Simulated Accident Conditions

A malfunction of the cooling system of high-level liquid waste (HLLW) and the failure of countermeasures may lead to the evaporation to dryness due to the loss of cooling functions (EDLCF) of the HLLW. In the EDLCF, ruthenium (Ru) can be released at a greater fraction to the initial amount than the other elements in HLLW by forming gaseous Ru. It is important to identify the chemical form of the released gaseous Ru to achieve a comprehensive understanding of the events impacting the source term assessment of Ru in this accident, such as particle formation, gas absorption, and deposition on migration pathways. In this study, we observed the ultraviolet/visible spectroscopy of the off-gas generated during the heating of a HLLW simulant. Employing a program that allows for the separation and quantification of known components within the spectrum [ruthenium tetroxide (RuO4), nitrogen dioxide, and nitric acid], we attempted to analyze the composition of gaseous Ru within the generated off-gas. Our findings revealed RuO4 as the main component of the gaseous Ru in the off-gas after comparing the total amount of released Ru and the RuO4 released amount obtained via spectroscopic analysis.

Stereocontrolled Synthesis of Phosphoproline Analogues Containing a trans-Fused Octahydroindole Bicyclic System.

Herein we report for the first time the diastereoselective synthesis of (2R,3aR,7aS)- and (2S,3aS,7aR)-octahydroindole-2-phosphonic acid (OicP trans-fused stereoisomers) from diethyl (R)- and (S)-phosphopyroglutamate derivative. The key steps of this procedure are the ruthenium tetroxide oxidation of enantiomerically pure diethyl (R)- and (S)-phosphoprolinate obtained through Katritzky's benzotriazole-oxazolidine methodology, a highly diastereoselective successive double 4,5-diallylation of diethyl (R)- and (S)-phosphopyroglutamate with allyl bromide and allyltrimethylsilane with a trans-addition mode, and a ring-closing metathesis with Grubbs' first-generation ruthenium catalyst.

Effect of operating conditions on the retention of ruthenium tetroxide (RuO4) by different solid traps

Mitigation of gaseous RuO4 is an important issue in nuclear safety in order to reduce potential radiological consequences, either in the context of severe accident arising on pressurized water reactors (oxidizing conditions) or in reprocessing plants (loss of cooling of fission product storage tanks). For the first time, RuO4 trapping was compared using three kinds of materials acting as solid traps: a functionalized MOF UiO-66-NH2, an amine-modified silica and a commercial cerium dioxide. Different experimental conditions of temperature, humidity and gas composition were investigated in order to mimic those prevailing under accident conditions at filtered containment venting system (FCVS) level or in ventilation ducts (gas mixture). At 50 C, the efficiency of UiO-66-NH2 for RuO4 trapping was both very high in dry gas and in presence of steam with decontamination factor (DF) in the range 104–105. Under more severe conditions, the retention performances slightly decrease, especially when NO2 was present in the feed gas due to some poisoning of adsorption sites. In presence of amino-modified silica, breakthrough of RuO4(g) occurred at an earlier stage due to its inferior adsorption capacity but the performances of the trap did not deteriorate in presence of steam and NO2 in gas mixture. Under similar conditions, cerium dioxide showed no retention of RuO4(g).

RTX 훈증 기법을 이용한 담배에 형성된 잠재지문의 현출

Cigarette-related garbage can be easily found on anywhere, even at the crime scene. Cigarette evidence can provide DNA evidence and have been used in investigation for a long time. If very small amounts of DNA are detected or in a mixture with contaminants, it is hard to analysis DNA In this case, fingerprints can be conclusive evidence to identify suspects. However, when 1,2-indanedione (1,2-IND) was applied to cigarettes, the background was stained and made it difficult to identify ridges. Therefore, latent fingerprint development research is needed in such case, and when DNA analysis is difficult on cigarettes. In this study, 1,2-IND and Ruthenium tetroxide (RTX) were used to compare the development of latent fingerprints on cigarettes, which are porous surfaces. On the filter part of cigarettes, latent fingerprints were clearly developed on both 1,2-IND and RTX, but on the body part of cigarettes, 1,2-IND reacted with tobacco leaves and showed a fluorescence reaction on the background, making it difficult to identify the ridges of the fingerprints. On the other hand, when RTX was applied, clear ridges were appeared on the body part of cigarettes. In addition, the RTX did not leave many stains on the background. The 1,2-IND is currently the most effective latent fingerprint development technique on porous surfaces but it is estimated to react with amino acid components contained in a cigarette. Therefore, when there is a need to develop latent fingerprints on cigarettes, it is confirmed that RTX reagent is much more effective than 1,2-IND reagent.

Protecting group enabled stereocontrolled approach for rare-sugars talose/gulose via dual-ruthenium catalysis

We herein report a convenient and highly stereocontrolled approach for rare and vital ᴅ-talo and ᴅ-gulo sugars directly from economical ᴅ-galactal through dual ruthenium-catalysis. The stereo-divergent strategy involves Ru(III)Cl3-catalyzed Ferrier glycosylation of ᴅ-galactal to give 2,3-unsaturated ᴅ-galactopyranoside, further selective functionalization of C-4 and C-6 position with diverse protecting groups and dihydroxylation with Ru(VIII)O4 generated in situ providing access to talo/gulo isomers. The α-anomeric stereoselectivity and syn-diastereoselectivity in glycosylation-dihydroxylation steps have been predominantly achieved by judicious selection of stereoelectronically diverse protecting groups. The synthetic utility of the dual-ruthenium catalysis was demonstrated for efficiently assembling the ᴅ-talose and/or ᴅ-gulose sugars in natural products and bioactive scaffolds.

Atomic Layer Deposition of Ruthenium Dioxide Based on Redox Reactions between Alcohols and Ruthenium Tetroxide

Atomic Layer Deposition of Ruthenium Dioxide Based on Redox Reactions between Alcohols and Ruthenium Tetroxide

INVESTIGATION OF SHORT-TERM CHEMICAL CHANGE IN STABLE RUTHENIUM ADDED TO RAINWATER THROUGH X-RAY ABSORPTION FINE STRUCTURE ANALYSIS.

Radioactive ruthenium may be accidentally released from spent nuclear fuel reprocessing plants to the surrounding environment. To obtain basic information regarding the effect of radioactive ruthenium on the environment, we investigated changes in the source form of stable ruthenium added to rainwater through X-ray absorption fine structure analysis. Ruthenium tetroxide (RuO4), ruthenium dioxide (RuO2), ruthenium nitrosyl nitrate (Ru(NO)(NO3)3) and ruthenium chloride (RuCl3) were employed as test sources. The Ru K-edge X-ray absorption near edge structure spectra acquired immediately after addition to ultrapure water differed among various sources. With RuO4 addition, a black deposit was observed 1 d after addition, and the spectrum was similar to that of RuO2. For RuO2, Ru(NO)(NO3)3 and RuCl3, no variances were observed between the spectra acquired immediately after addition and 1 d after addition. These results indicate that the chemical forms of RuO2, Ru(NO)(NO3)3 and RuCl3 did not change within a 1-d span in rainwater.

Ruthenium tetroxide oxidation of N-methyl-isoxazolidine: Computational mechanistic study

In this paper, we report a mechanistic study of RuO 4 -catalyzed oxidation on the 2-methylisoxazolidine through computational methods. The investigation was performed taken into consideration that the oxidation could take place on different sites of the substrate. This reaction occurs in two steps, involving a double H-transfer. In particular, the rate-determining one implies a [3 + 2] one-step, but asynchronous mechanism. In the first step, when methyl propanoate is used as solvent, the formation of an ion pair, which affords to the product, is involved. Furthermore, the study highlights that all carbon atoms of the isoxazolidine system, near to the heteroatoms, can undergo the oxidation process. The detected selectivity is correlated to the stability of the corresponding carbocations, leading to the N -methylisoxazolidin-3-one as preferred product.

Aspects of thermodynamic parameters with a kinetic approach of transition metal catalysed by potassium bromate oxidation of methyl diethylene glycol (MDG) in alkaline medium

The kinetic data obtained in ruthenium(VI) catalysed oxidation of methyldiethylene glycol (MDG) in alkaline medium using potassium bromate as oxidant and transition metal ruthenium tetroxide as a homogenous catalyst. In this kinetic reaction, Hg(OAc)2 acts as a liberated bromide ion scavenger. The result shows first order with respect to KBrO3, methyldiethylene glycol (MDG) and transition metal respectively. It shows zero order dependences of the reaction on aqueous sodium hydroxide, which is used as medium of the reaction and also zero effect of mercuric acetate. In this catalysed reaction, ionic strength has positive effect. The corresponding acid was found to be main oxidation product. A plausible reaction mechanism in agreement with kinetic results was put forward.

Chemoselective Oxidation of Isoxazolidines with Ruthenium Tetroxide: A Successful Intertwining of Combined Theoretical and Experimental Data.

The direct oxidation reaction of isoxazolidines plays an important role in organic chemistry, leading to the synthesis of biologically active compounds. In this paper, we report a computational mechanistic study of RuO4-catalyzed oxidation of differently N-substituted isoxazolidines 1a–c. Attention was focused on the endo/exo oxidation selectivity. For all the investigated compounds, the exo attack is preferred to the endo one, showing exo percentages growing in parallel with the stability order of transient carbocations found along the reaction pathway. The study has been supported by experimental data that nicely confirm the modeling results.

The Behavior of Ruthenium in Copper Electrowinning

The recycling of material containing precious metals can lead to the entry of ruthenium into the copper electrowinning process, by so far unknown effects. There, ruthenium is oxidized to highly volatile ruthenium tetroxide. In order to avoid ruthenium losses during electrolysis, the oxidation behavior of ruthenium in copper electrowinning was investigated by testing different oxygen overvoltages using lead alloy and diamond anodes. Furthermore, the temperature and the current density were varied to investigate a possible chemical or electrochemical reaction. The results of the study show that ruthenium is not directly electrochemically oxidized to ruthenium tetroxide at the anode. Especially at anodes with high oxygen overvoltage, the formation of other oxidants occurs parallel to the oxygen evolution in the electrolyte. These oxidants oxidize ruthenium compounds to highly volatile ruthenium tetroxide by chemical reactions. These reactions depend mainly on temperature; the formation of the active oxidants depends on the anodic potential. To avoid ruthenium losses in the copper electrowinning process, anodes with a low anodic potential should be used at low electrolyte temperatures.

Cover Feature: Single‐Atomic Ruthenium Active Sites on Ti3C2 MXene with Oxygen‐Terminated Surface Synchronize Enhanced Activity and Selectivity for Electrocatalytic Nitrogen Reduction to Ammonia (ChemSusChem 3/2022)

The Cover Feature shows a novel design of Ru single atoms anchored on Ti3C2O to catalyze the nitrogen reduction reaction. A series of advanced characterizations demonstrates that the enhanced activity and selectivity of nitrogen reduction to ammonia can be attributed to the structure of Ru–O4 coordination that permits the hydrogenation of *NNH2 to *NHNH2 in a novel distal/alternating hybrid path with lower energy. More information can be found in the Research Article by G. Chen et al.

Capture and immobilization of gaseous ruthenium tetroxide RuO4 in the UiO-66-NH2 metal-organic framework.

106Ru is a radioactive isotope usually generated by the nuclear industry within power plant reactors. During a nuclear accident, 106Ru reacts with oxygen, leading to the production of highly volatile ruthenium tetroxide RuO4. The combination of volatility and radioactivity makes 106RuO4, one of the most radiotoxic species and justifies the development of a specific setup for its capture and immobilization. In this study, we report for the first time the capture and immobilization of gaseous RuO4 within a porous metal-organic framework (UiO-66-NH2). We used specific installation for the production of gaseous RuO4 as well as for the quantification of this gas trapped within the filtering medium. We proved that UiO-66-NH2 has remarkable affinity for RuO4 capture, as this MOF exhibited the worldwide highest RuO4 decontamination factor (DF of 5745), hundreds of times higher than the DF values of sorbents daily used by the nuclear industry (zeolites or activated charcoal). The efficiency of UiO-66-NH2 can be explained by its pore diameters well adapted to the capture and immobilization of RuO4 as well as its conversion into stable RuO2 within the pores. This conversion corresponds to the reactivity of RuO4 with the MOF organic sub-network, leading to the oxidation of terephthalate ligands. As proved by powder X-ray diffraction and NMR techniques, these modifications did not decompose the MOF structure.

Atomic Layer Deposition of Ruthenium Dioxide Thin Films Using RuO4 and Alcohols As Reactants

Ruthenium dioxide (RuO2) is the most stable oxide of Ru and has attracted tremendous attention in different applications such as supercapacitors, catalysis, and electrochemical devices. The high conductivity, good chemical stability, a work function value that is even higher than metallic Ru are few properties that make this material so demanding1. Although RuO2 is such an interesting material, atomic layer deposition (ALD) literature reports on this material are scarce. The existing ALD processes based on metalorganic Ru precursors necessitate careful tuning of the O2 partial pressure in order to deposit RuO2 films, as Ru metal is produced at lower O2 partial pressures. Furthermore, reported processes often require high temperature (>180°C) depositions and suffer from high nucleation delays, up to several hundred cycles in some cases.2 In this scenario, we present a novel ALD strategy solely for the synthesis of RuO2 films that takes advantage of the reaction between various alcohols and ruthenium tetroxide (RuO4) without any significant nucleation delay. The process, which uses methanol and RuO4 as reactants, exhibits a growth per cycle (GPC) of 1 angstrom (Å) per cycle (Figure 1a and 1b) at a substrate temperature as low as 60 °C. A constant GPC of 1Å is obtained in the temperature window of 60 °C-120 °C, while the RuO4 precursor is known to decompose above 125 °C.3 The depositions result in amorphous RuO2 films, as confirmed with X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements. The films can be transformed into crystalline rutile RuO2 by annealing in helium or air at around 400 °C (Figure 1c). The films are conductive, as is evident from the resistivity value of 230 µΩ.cm for a 20 nm film, and the conductivity improved slightly after the anneal.Interestingly, the reaction of other alcohol molecules such as ethanol, 1-propanol, and 2-propanol with RuO4 results in a higher GPC compared to the methanol-based process and it is concluded that the GPC can be increased by increasing the number of carbon atoms in the alcohol chain (Figure 1d). However, all these processes employing different alcohols display typical self-saturating ALD properties. The reaction mechanism of the developed ALD approach was studied in depth using in situ mass spectrometry and in vacuo XPS studies. A reaction mechanism is proposed based on these learnings, wherein during the first half-cycle, alcohol molecules are oxidized into aldehyde and H2O on a RuO2 surface. This in turn causes the partial reduction of the surface RuO2 layer into RuOx or Ru. During the next half-cycle RuO4 oxidizes the surface back to RuO2 and additional RuO2 is deposited on the surface. References Ryden, W.; Lawson, A.; Sartain, C. C., Electrical Transport Properties of Ir O 2 and Ru O 2. Physical Review B 1970, 1 (4), 1494.Austin, D. Z.; Jenkins, M. A.; Allman, D.; Hose, S.; Price, D.; Dezelah, C. L.; Conley Jr, J. F., Atomic layer deposition of ruthenium and ruthenium oxide using a zero-oxidation state precursor. Chemistry of Materials 2017, 29 (3), 1107-1115.Minjauw, M. M.; Dendooven, J.; Capon, B.; Schaekers, M.; Detavernier, C., Atomic layer deposition of ruthenium at 100° C using the RuO 4-precursor and H 2. Journal of Materials Chemistry C 2015, 3 (1), 132-137. This work is funded by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No.765378. Figure 1

Hierarchical Microphase Behaviors of Chiral Block Copolymers under Kinetic and Thermodynamic Control

Hierarchical Microphase Behaviors of Chiral Block Copolymers under Kinetic and Thermodynamic Control

A theoretical investigation on the intermolecular potential curve between ruthenium tetroxide and NOX (X = 1, 2)

AbstractRuthenium tetroxide (RuO4) is one of chemical species of fission products assumed to be released to the environment during a severe accident of nuclear facilities and a target compound to assess the amount produced, reactivity, mobility and release timing. In this article, the NOX (X = 1, 2) adduct formation of RuO4 has been investigated, based on the potential energy curve (PEC) evaluated by UM06, UTPSSh, CASSCF, and CASPT2 methods. At several stationary points, CCSD and LR‐CCSD(T) energies are also computed for a comparison. The PEC shows that there is an activation barrier to form the NOX adduct and that the process is endothermic in terms of free energy. In the system, the electron transfer occurs from NOX to RuO4 when the bond between the nitrogen and oxo ligand is formed. It has been discussed in detail using active orbitals, weight of electron configurations and spin population obtained by CASSCF.

Nanoparticle size distribution quantification from transmission electron microscopy (TEM) of ruthenium tetroxide stained polymeric nanoparticles

HypothesisDynamic Light Scattering (DLS) generated particle size distributions (PSD) of polymer-stabilized nanoparticles are dependent on the optimization parameters used to generate an inversion solution fit to the measured autocorrelation function. The accuracy of the DLS PSD average and polydispersity can be determined by comparing analyzed Transmission Electron Microscopy (TEM) images with the DLS results if the TEM measured sizes can be corrected for the thickness of the hydrated polymer corona that impacts particle hydrodynamics but is a collapsed, desiccated shell in the TEM images. ExperimentsNanoparticles were prepared by Flash NanoPrecipitation with either poly(ethylene glycol) (PEG) or hydroxypropyl methylcellulose acetate succinate (HPMCAS) stabilizing polymers. Solvated nanoparticle size distributions were measured by DLS in aqueous media. The same nanoparticle dispersions were lyophilized onto TEM grids and stained by ruthenium tetroxide (RuO4) vapor to improve electron contrast. Desiccated particle size distributions were generated by measuring a minimum of 300 particle diameters in the stained TEM images. FindingsUsing our protocol for staining soft matter nanoparticles in TEM measurements, we have quantitatively analyzed the correlation between DLS and TEM generated PSDs. Average diameters disagree by the hydrated polymer corona thickness for each stabilizer due to the high-vacuum TEM environment, with 21.4 nm for PEG and 51.2 nm for HPMCAS. While corrected average diameter agrees within 10% for each technique, DLS consistently over-estimates the standard deviation of the PSD by 100% compared to the TEM measurement.

Comparative effect of osmium tetroxide and ruthenium tetroxide on Lacazia loboi ultrastructure.

Lobomycosis is a skin infection produced by the fungus Lacazia loboi, which mainly affects some indigenous and afro-descendant populations in Tropical America. We previously reported the comparative effect of osmium tetroxide (OsO4 ) and ruthenium tetroxide (RuO4 ) in the electron microscopy (EM) of other related microorganisms. The objective of this study is to compare the effect of postfixation with OsO4 and RuO4 in the ultrastructure of L. loboi yeasts. Skin biopsies on patients diagnosed with lobomycosis were fixed in glutaraldehyde at 3% and postfixed in the following solutions: (a) 1% OsO4 , (b) 0.2% RuO4 , and (c) OsO4 at 1% followed by RuO4 at 0.2%. They were then processed using the conventional method for EM. Unlike OsO4, the treatment with RuO4 revealed different shades of gray and electron dense bands in the cell wall and other cell components of L. loboi. The most notable finding was the presence of radial filamentous structures around the yeast, which made the image look like the sun. Postfixation with RuO4 revealed ultrastructural details that had not been previously reported for L loboi. The combined use of OsO4 and RuO4 in EM of microorganisms with cell walls can be useful to evaluate the effect of microbicide substances.

Decomposition behavior of gaseous ruthenium tetroxide under atmospheric conditions assuming evaporation to dryness accident of high-level liquid waste

ABSTRACT Emphasis has been placed on the behavior of ruthenium (Ru) in the evaporation to dryness accident due to the loss of cooling functions (EDLCF) of high-level liquid waste in fuel reprocessing plants. It is because Ru would form volatile compounds such as ruthenium tetroxide (RuO4) and could be released into the environment with other coexisting gasses such as nitric acid (HNO3), water (H2O). To contribute to the safety evaluation of this accident, we experimentally evaluated the decomposition and chemical change behavior of the gaseous RuO4 (RuO4(g)) under the various atmospheric conditions: temperature and composition of coexisting gasses. As a result, the behavior of the RuO4(g) was diverse depending on the atmospheric conditions. In the experiments with the dry air or H2O vapor, decomposition of RuO4(g) was observed. In the experiment with the mixed gas which containing HNO3, almost no decomposition of the RuO4(g) was observed, and chemical form of the RuO4(g) was retained.