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BACKGROUND: Sodium chlorate (NaClO3) is extensively used in the paper industry, but its production uses strictly regulated highly toxic Na2Cr2O7 to reach high hydrogen evolution reaction (HER) Faradaic efficiencies. It is therefore important to find alternatives either to replace Na2Cr2O7 or reduce its concentration. RESULTS: The Na2Cr2O7 concentration can be significantly reduced by using Na2MoO4 as an electrolyte co-additive. Na2MoO4 in the millimolar range shifts the platinum cathode potential to less negative values due to an activating effect of cathodically deposited Mo species. It also acts as a stabilizer of the electrodeposited chromium hydroxide but has a minor effect on the HER Faradaic efficiency. X-ray photoelectron spectroscopy (XPS) results show cathodic deposition of molybdenum of different oxidation states, depending on deposition conditions. Once Na2Cr2O7 was present, molybdenum was not detected by XPS, as it is likely that only trace levels were deposited. Using electrochemical measurements and mass spectrometry we quantitatively monitored H-2 and O-2 production rates. The results indicate that 3 mu mol L-1 Na2Cr2O7 (contrary to current industrial 10-30 mmol L-1) is sufficient to enhance the HER Faradaic efficiency on platinum by 15%, and by co-adding 10 mmol L-1 Na2MoO4 the cathode is activated while avoiding detrimental O-2 generation from chemical and electrochemical reactions. Higher concentrations of Na2MoO4 led to increased oxygen production. CONCLUSION: Careful tuning of the molybdate concentration can enhance performance of the chlorate process using chromate in the micromolar range. These insights could be also exploited in the efficient hydrogen generation by photocatalytic water splitting and in the remediation of industrial wastewater.

Molybdenum is an essential dietary trace element required for several critical enzyme systems. High intake is associated with toxicity in ruminants and animal studies. The proposed therapeutic use of molybdenum-based drugs poses a potential risk for accumulation through chronic administration of therapeutic doses of this element. The current experiment was designed to study the effect of daily dosing of a molybdenum compound, bis-choline tetrathiomolybdate (TTM), in Sprague Dawley rats using laser ablation inductively coupled plasma time-of-flight mass spectrometry (LA-ICP-ToF-MS) and two dosing levels of TTM for up to 3 months. To investigate if molybdenum accumulation was associated with tissue toxicity, histopathology, haematology and clinical biochemistry markers of toxicity were incorporated into the study design. There were no behavioural signs of toxicity to the rats, and no clinical or anatomic pathology was associated with treatment. The current data did show a progressive accumulation of molybdenum within the adrenal gland, kidneys, liver, spleen, brain and testes. Although this was not associated with tissue toxicity within the 3-month study design, greater exposure over a longer period of time has the potential for producing adverse pathophysiological cellular function. Tissue toxicity, as a result of local excessive accumulation of molybdenum over time, has clear implications for the therapeutic use of molybdenum in humans and demands sensitive monitoring of tissue molybdenum levels to avoid toxicity. The current study highlights the shortcomings of conventional biomonitoring approaches to detect molybdenum accumulation with the goal of avoiding molybdenum-associated toxicity.

International audience; We present here the syntheses and structural characterizations of inorganic polymeric cluster compounds, Cs[Mn(salen)](3)[{Mo6Br6Se2}(CN)(6)] (1) and (H3O)(TBA)[Mn(salen)](2)[{Mo6Br6Se2}(CN)(6)] (2) (TBA=tetrabutylammonium ((n-C4H9)(4)N+)), built-up from [{Mo6Br6Se2}(CN)(6)](4-) molecular building blocks and Mn(salen)(+) complexes (salen = salen = N,N '-bis(salicylidene)ethylenediamine). The nature of additional counter cations (i. e. Cs+ or TBA(+)) enables to control the interactions between the [{Mo6Br6Se2}(CN)(6)](4-) building blocks and the Mn(salen)(+) groups. Thus, 1 was obtained by slow diffusion of a methanol solution of K2Cs2[{Mo6Br6Se2}(CN)(6)] cluster compound into a methanol solution of Mn(salen)ClO4. 2 was obtained in a similar way but after the addition of tetrabutylammonium bromide into the solution of Mn(salen)ClO4. 1 is a bimetallic 3D coordination compound ( R3?c ${R\bar{3}c}$ ) and 2 is a bimetallic 2D compound ( P1? ${P\bar{1}}$ ). Structural correlations between 1 and 2 are discussed and compared with relevant examples found in the literature.

To assess the prognostic capabilities of various diagnostic modalities for childhood brachial plexus injuries (BPIs) and brachial plexus birth injury (BPBI) and postneonatal BPI.In this single-center retrospective cross-sectional study, we examined children with BPIs diagnosed or confirmed by electrodiagnostic studies between 2013 and 2020, and compared the prognostic value of various components of the electrophysiologic findings, magnetic resonance imaging (MRI) data, and the Active Movement Scale (AMS). We developed scoring systems for electrodiagnostic studies and MRI findings, including various components of nerve conduction studies and electromyography (EMG) for electrodiagnostic studies.We identified 21 children (10 females and 11 males) aged 8 days to 21 years (mean 8y 6.95mo) who had a total of 30 electrodiagnostic studies, 14 brachial plexus MRI studies, and 10 surgical procedures. Among the diagnostic modalities assessed, brachial plexus MRI scores, EMG denervation scores, and mean total EMG scores were the most valuable in predicting surgical versus non-surgical outcomes. Correspondingly, a combined MRI/mean total EMG score provided prognostic value.Brachial plexus MRI scores and specific electrodiagnostic scores provide the most accurate prognostic information for children with BPI. Our grading scales can assist a multidisciplinary team in quantifying results of these studies and determining prognosis in this setting.A new scoring system to quantify results of electrodiagnostic and magnetic resonance imaging (MRI) studies is presented. Severity of denervation has good prognostic value for childhood brachial plexus injuries (BPIs). Composite electromyography scores have good prognostic value for childhood BPIs. Brachial plexus MRI has good prognostic value for childhood BPIs.

On the basis of the higher order perturbation formulas of g-factors for a 4d1 group in tetragonally compressed octahedra, the g-factors, optical absorption, local structure and their concentration dependences of pentavalent molybdenum in 40PbO-(10-x)Y2 O3 -50P2 O5 :xMoO3 (1 ≤ x ≤ 5 mol%) glass are uniformly investigated. The experimental optical absorption spectra and g factors for Mo5+ at various concentrations x are reasonably regenerated by using the reasonable exponential concentration functions of the cubic field parameter Dq, covalent factor N and relative tetragonal compression ratio ρ. The tetragonal compression ratio ρ due to the Jahn-Teller effect was found in the range of 3.8-4.2%. The decreasing trend of Dq and N and the increasing trend of ρ with concentration can be interpreted as the fact that the variations of MoO3 and Y2 O3 concentrations lead to the modulations of local structure and electron cloud distribution around Mo5+ , associated with the adjustment of the glass network. The concentration dependence of optical basicity is also analyzed for the above glass systems.

During the reduction of molybdenum trioxide (MoO3 ) to metallic molybdenum, the first reduction step yielding molybdenum dioxide as an intermediary product is of crucial importance. In this study, we examined the impact of the parameters reduction temperature, water influx, and potassium content on the hydrogen reduction of this first reaction step. Beginning from the same starting material, the chemical vapor transport mechanism was utilized to yield the phase pure MoO2 . Analyses including powder X-ray diffraction, inductively coupled plasma-mass spectrometry, scanning electron microscopy, and high performance optical microscopy were performed on the product phases. Modulations of the specific surface areas of molybdenum dioxide ranging from 2.28 to 0.41 m2 /g were possible. Furthermore, a distinct shift from small plate-like grains to cuboid-like forms was achieved.

A new [PCCP]-coordinated molybdenum platform comprising a coordinated alkyne was employed for the cleavage of molecular dinitrogen. The coordinated η2 -alkyne was left unaffected during this reduction. DFT calculations suggest that the reaction proceeds via an initially generated terminal N2 -complex, which is converted to a dinuclear μ-(η1 :η1 )-N2 -bridged intermediate prior to N-N bond cleavage. Protonation, alkylation and acylation of the resulting molybdenum nitrido complex led to the corresponding N-functionalized imido complexes. Upon oxidation of the N-acylated imido derivative in MeCN, a fumaronitrile fragment was built up via C-C coupling of MeCN to afford a dinuclear molybdenum complex. The key finding that the strong N≡N bond may be cleaved in the presence of a weaker, but spatially constrained C≡C bond contradicts the widespread paradigm that coordinated alkynes are in general more reactive than gaseous N2 .

The development of NIR emitters based on earth‐abundant elements is an important goal in contemporary science. We present here Cr(0), Mo(0), and W(0) carbonyl complexes with a pyridyl‐mesoionic carbene (MIC) based ligand. A detailed photophysical investigation shows that all the complexes exhibit dual emissions in the VIS and in the NIR region. The emissive excited states are assigned to two distinct triplet states by time‐resolved emission and step‐scan FTIR spectroscopy at variable temperature, supported by density functional theory. In particular, the NIR emissive triplet state exhibits unprecedented lifetimes of up to 600±10 ns and quantum yields reaching 1.7 ⋅ 10−4 at room temperature. These are the first examples of Cr(0), Mo(0) and W(0) complexes that emit in the NIR II region., This work presents emissive Cr(0), Mo(0), and W(0) complexes that contain a bidentate pyridyl‐mesoionic carbene ligand and CO coligands. These systems exhibit dual vis and NIR II emissions at room temperature. The emissive excited triplet states were characterized by temperature‐dependent luminescence and step‐san FTIR spectroscopy in combination with density functional theory. The NIR quantum yield increases from Cr(0) over Mo(0) to W(0), reaching a very high value of 1.4 ⋅ 10−3 at room temperature.

The construction of the C-N bond with nitroaromatics and boric acids using highly efficient and recyclable catalyst remains a challenging project. In this contribution, we have disclosed that the guest-host nanoporous MoO 3 confined in silica is efficient heterogeneous catalyst for C-N cross-coupling of nitroaromatics with aryl- or alkyl-boronic acids to deliver N -arylamines, and with desirable multiple reusability. Experimental results suggest that silica not only makes the Mo species be heterogenized in the confined mesoporous microenvironment but also conspicuously reduces the reaction induction period and regulates the chemical efficiency of the targeted product. The well-shaped MoO 3 @-m-SiO 2 catalyst exhibits improved catalytic performance both in yield and TON value contrast with that of homogeneous Mo catalysis, commercial Pd/C, or MoO 3 nanoparticals (NPs). This approach offers a brand-new avenue for the heterogeneous synthesis of valuable bioactive molecules.

Compression molded composites were prepared through a water-assisted mixing of an aqueous suspension of poly(ethylene-co-acrylic acid), additive,and pulp fibers [thermomechanical pulp (TMP) or dissolving pulp (DP)]. The lubricating additives used were magnesium stearate (MgSt) and molybdenum disulphide (MoS2). The composite materials had dry pulp contents ranging from 30 to 70 wt% and 5 wt% additive relative to the weight of the pulp. The adsorption of the additives onto the fibers was confirmed by scanning electron microscopy and energy dispersive X-ray analysis. DMA showed that MgSt and MoS2 gave similar interphase properties for the TMP samples at all loading contents, but the combination of MgSt and MoS2 improved the overall properties of the DP-based composites. The tensile modulus, at 70 wt% fiber content (TMP or DP), increased compared to the matrix by a factor of 6.3 and 8.1, without lubricants, and by a factor of 8 and 10.7, with lubricants, respectively. The increase in melt viscosity observed for the lubricated samples was greater for the TMP-based samples containing MoS2. At a lubricant content of 5 wt%, in 30 wt% TMP, the MoS2 behaved as both a lubricant and compatibilizer.

Programmable smart materials that can respond locally to specific stimuli hold great potential for many applications, but controllable fabrication of these materials remains challenging. This work reports the development of novel programmable anisotropic materials with both magnetic and photothermal stimuli-responsiveness, which are fabricated by anchoring thermosensitive poly(N-isopropyl acrylamide) (PNIPAm) and magnetic Fe

Corrosion and wear are commonly found at the taper-trunnion connection of modular total hip arthroplasty (THA) explanted devices. While metal/metal (M/M) modular taper-trunnion connections exhibit more wear/corrosion than ceramic/metal (C/M) modular taper-trunnion connections, damage is present in both, regardless of material. This study used a combination of assessment techniques including clinical data, visual scoring assessment, optical imaging, profilometry, and x-ray photoelectron microscopy (XPS), to investigate wear mechanisms and damage features at the modular taper-trunnion connection of 10 M/M and 8 C/M explanted THAs. No correlation was found between any demographic variable and corrosion wear and assessment scores. All assessment techniques demonstrated that the stem trunnions had more damage than head tapers for both explant groups and agreed that C/M explants had less corrosion and wear compared to M/M explants. However, visual assessment scores differed between assessment techniques when evaluating the tapers and trunnions within the two groups. Profilometry showed an increase (p

The development of C(sp(3))−H functionalizations of free carboxylic acids has provided a wide range of C−C and C−Y (Y = heteroatom) bond-forming reactions that both complement and expand upon what can be achieved through conventional methods. Additionally, C−H functionalizations have lent themselves to the one-step preparation of a number of valuable, synthetic motifs, that are often difficult to prepare through conventional methods. Herein, we report a β- or γ-C(sp(3))−H carbonylation of free carboxylic acids using Mo(CO)(6) as a convenient solid CO source and enabled by a bidentate ligand, leading to convenient syntheses of cyclic anhydrides. Among these, the succinic anhydride products are versatile stepping stones for the mono-selective introduction of alkyl, alkenyl, aryl, alkynyl, boryl, silyl, fluoro, iodo, and thiophenyl groups at the β position of the parent acids by decarboxylative functionalizations, thus providing a divergent strategy to synthesize a myriad of carboxylic acids inaccessible by previous β-C−H activation reactions. The enantioselective carbonylation of free cyclopropanecarboxylic acids has also been achieved using a chiral bidentate thioether ligand.

Temperature-programmed reduction of transition-metal phosphate precursors is the most commonly used method for the preparation of transition-metal phosphides (a new class of versatile metal catalysts), but the reduction processes are still not clear. Here we describe the construction of a temperature-programmed reduction-infrared spectroscopy apparatus (TPR-IR) to analyze the gas flows during the reduction of nickel, molybdenum, and tungsten phosphates. PH3 and Pn+ species already appeared in the gas flows at low temperature (ca. 200 °C), and PH3 was involved in the formation of phosphides. The emission of PH3 and Pn+ during the reduction of the molybdenum and tungsten phosphates was smaller than that of the nickel phosphate. Ni2 P drastically accelerated the formation of the PH3 and Pn+ . These results explain why excess phosphorus is needed for the preparation of Ni2 P, and also demonstrate that the TPR-IR technique is an efficient method to understand the complex processes of catalyst preparation.

Water-dispersible two-dimensional (2D) materials are desirable for diverse applications. Aqueous dispersions make processing safer and greener and enable evaluation of these materials on biological and environmental fronts. To evaluate the effects of 2D materials with biological systems, obtaining dispersions without additives is critical and has been a challenge. Herein, a method was developed for obtaining additive-free aqueous dispersions of 2D materials like transition metal dichalcogenides and hexagonal boron nitride (h-BN). The nanosheet dispersions were investigated through spectroscopic and microscopic methods, along with the role of size on stability. The aqueous media enabled investigations on cytocompatibility and enzymatic degradation of molybdenum disulphide (MoS2 ) and h-BN. Cytocompatibility with mixed glial cells was observed up to concentrations of 100 μg mL-1 , suggesting their plausible usage in bioelectronics. Besides, biodegradation using human myeloperoxidase (hMPO) mediated catalysis was investigated through Raman spectroscopy and electron microscopy. The findings suggested that additive-free 2H-MoS2 and h-BN were degradable by hMPO, with 2H-phase exhibiting better resistance to degradation than the 1T-phase, while h-BN exhibited slower degradation. The findings pave a path for incorporating 2D materials in the burgeoning field of transient bioelectronics.

Sodium‐ion batteries are considered one of the most promising candidates for affordable and scalable energy storage as required in smart grid and renewable energy. One of the principal challenges sodium‐ion batteries being faced is to search suitable anode materials that can accommodate and store large amounts of Na+ ions reversibly and sustainably at reasonable galvanostatic rates. Molybdenum‐based materials such as oxides and sulfides might meet this challenge as they afford a capacity much greater than those of the carbonaceous materials and exhibit rich Na‐reaction chemistry. However, these materials are facing several technical issues, such as multiple‐phase transformation, particle pulverization as the result of volume swelling, and low surface activity during sodiation/desodiation. To tackle these issues, materials design and engineering are of indispensability. In this brief review, we present a state‐of‐the‐art overview of the research progress of molybdenum‐based materials for sodium storage, and highlight materials engineering strategies that are capable of addressing the mentioned challenges. We also offer valuable insights into their further development direction and discuss their potentiality in practical batteries.

Here, we introduce an innovative "poison arrowhead" approach for disinfection based on a nanosheet bacterial inactivation system that acts synergistically to achieve sterilization rates of >99.99 % (Escherichia coli) over an ultrashort time period (≈0.5 min). The two-dimensional MoS2 "arrowhead" configuration has a sharp edge structure that enables the vigorous extraction of lipids from cell membranes and subsequent membrane disruptions. In the presence of permonosulfate, a strong oxidant, sulfur vacancies containing MoS2 activate the stable molecules, which in turn produce reactive oxygen species (ROS) from edge sites to basal areas. This process not only scavenges some portion of the phospholipids to allow for MoS2 surface refreshment but also directly attacks proteins thereby inflicting further damage to injured cells and amplifying the cell-membrane-destructive stresses toward pathogenic microorganisms. With small amounts of the new material, we successfully disinfected natural water (≈99.93 % inactivation in terms of total bacteria) within 30 s.

Spent MoSi2 and MoB were used as raw materials to prepare multilayer MoSi2/MoB coating on molybdenum by the two‐step method of Slurry Deposition and Spark Plasma Sintering. The results showed dense ...

Herein, we present a new strategy for the synthesis of 2D porous MoP/Mo2 N heterojunction nanosheets based on the pyrolysis of 2D [PMo12 O40 ]3- -melamine (PMo12 -MA) nanosheet precursor from a polyethylene glycol (PEG)-mediated assembly route. The heterostructure nanosheets are ca. 20 nm thick and have plentiful pores ( 55 mA cm-2 in neutral medium and >190 mA cm-2 in alkaline medium.

International audience; Recrystallization of Cs-2[Mo6X14] (X=Cl, Br) was examined using typical organic solvents, i. e., methanol (CH3OH), acetone (CH3COCH3) and dichloromethane (CH2Cl2) in order to modify crystal structures and optoelectronic properties by promoting purity or inducing insertion of guest molecules. To this context, we performed recrystallization in solvent liquid and exposure of Cs-2[Mo6X14] to vapor of those solvents. Subsequent single crystal X-ray diffraction analyses revealed that three new types of compounds which contain high concentration of guest organic solvent molecules were obtained. Indeed, the newly found structures are Cs-2[Mo6Cl14] . 3CH(3)OH and Cs-2[Mo6X14] . 6CH(3)COCH(3) belonging to triclinic P1? space group, and Cs-2[Mo6X14] . 4CH(2)Cl(2) belonging to tetragonal P4/mnc space group. Although breaking of centrosymmetry by insertion of the guest molecule is interesting in terms of optoelectronic properties, all those new compounds belong to centrosymmetric space groups. As DFT calculations for those new compounds show that the guest molecules, such as CH3OH, do not affect the atomic arrangements and electronic features of the [Mo6X14](2-) cluster based unit, they incorporated with the lattice while keeping with the electrostatic interaction between the [Mo6X14](2-) and Cs+ ions regardless of the very high concentration of the guest solvent molecules.

As an approach towards unraveling the nitrogenase mechanism, we have studied the binding of CO to the active‐site FeMo‐cofactor. CO is not only an inhibitor of nitrogenase, but it is also a substrate, undergoing reduction to hydrocarbons (Fischer–Tropsch‐type chemistry). The C−C bond forming capabilities of nitrogenase suggest that multiple CO or CO‐derived ligands bind to the active site. Herein, we report a crystal structure with two CO ligands coordinated to the FeMo‐cofactor of the molybdenum nitrogenase at 1.33 Å resolution. In addition to the previously observed bridging CO ligand between Fe2 and Fe6 of the FeMo‐cofactor, a new ligand binding mode is revealed through a second CO ligand coordinated terminally to Fe6. While the relevance of this state to nitrogenase‐catalyzed reactions remains to be established, it highlights the privileged roles for Fe2 and Fe6 in ligand binding, with multiple coordination modes available depending on the ligand and reaction conditions., Besides reducing dinitrogen, nitrogenases reduce CO to hydrocarbons, mediating C−C bond formation between multiple CO‐derived ligands. To shed light on how multiple C‐based ligands bind to the active site, we report a 1.33 Å resolution crystal structure of two CO ligands coordinated to the FeMo‐cofactor of molybdenum nitrogenase (see picture). The second CO ligand is coordinated to Fe6 in a previously unreported ligand binding mode.

Bifunctional hydrogen electrocatalysis (hydrogen-oxidation and hydrogen-evolution reactions) in alkaline solution is desirable but challenging. Among all available electrocatalysts, Ni-based materials are the only non-precious-metal-based candidates for alkaline hydrogen oxidation, but they generally suffer from low activity. Here, we demonstrate that properly alloying Ni with Mo could significantly promote its electrocatalytic performance. Ni4 Mo alloy nanoparticles are prepared from the reduction of molybdate-intercalated Ni(OH)2 nanosheets. The final product exhibits an apparent hydrogen-oxidation activity exceeding that of the Pt benchmark and a record-high mass-specific kinetic current of 79 A g-1 at an overpotential of 50 mV. A superior hydrogen-evolution performance is also measured in alkaline solution. These experimental data are rationalized by our theoretical simulations, which show that alloying Ni with Mo significantly weakens its hydrogen adsorption, improves the hydroxyl adsorption and decreases the reaction barrier for water formation.