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Phosphaphenalenes, extended π conjugates with the incorporation of phosphorus, are attractive avenues towards molecular materials for the applications in organic electronics, but their electron accepting ability have not been investigated. Herein we present systematic studies on the reductive behavior of a representative phosphaphenalene and its oxide by chemical and electrochemical methods. The chemical reduction of the phosphaphenalene by alkali metals reveals the facile P−C bond cleavage to form phosphaphenalenide anion, which functions as a transfer block for structure modification on the phosphorus atom. In contrast, the pentavalent P‐oxide reacts with one or two equivalents of elemental sodium to form stable radical anion and dianion salts, respectively. [ABSTRACT FROM AUTHOR]

Chemical reduction of a [4]cumulene with cesium metal was explored, and the structural changes stemming from electron acquisition are detailed using X‐ray crystallography. It is found that the [4]cumulene undergoes dramatic geometric changes upon stepwise reduction, including bending of the cumulenic core and twisting of the endgroups from orthogonal to planar. The structural deformation is consistent with early theoretical reports that suggest that the twisting should occur upon reduction of both even and odd [n]cumulenes. The current results, on the other hand, are inconsistent with a previous experimental study of a [3]cumulene in which the predicted twisting is not observed upon reduction. DFT calculations reveal that the barrier to deformation is an order of magnitude lower in a [3]cumulene than a [4]cumulene, allowing the barrier to be overcome in the solid‐state. [ABSTRACT FROM AUTHOR]

Borane–trimethylamine complex (Me3N·BH3; BTM) is the most stable of the amine–borane complexes that are commercially available, and it is cost-effective. It is a valuable reagent in organic chemistry with applications in the reduction of carbonyl groups and carbon–nitrogen double bond reduction, with considerable examples in the reduction of oximes, hydrazones and azines. The transfer hydrogenation of aromatic N-heterocycles and the selective N-monomethylation of primary anilines are further examples of recent applications, whereas the reduction of nitrobenzenes to anilines and the reductive deprotection of N-tritylamines are useful tools in the organic synthesis. Moreover, BTM is the main reagent in the regioselective cleavage of cyclic acetals, a reaction of great importance for carbohydrate chemistry. Recent innovative applications of BTM, such as CO2 utilization as feedstock and radical chemistry by photocatalysis, have extended their usefulness in new reactions. The present review is focused on the applications of borane–trimethylamine complex as a reagent in organic synthesis and has not been covered in previous reviews regarding amine–borane complexes. [ABSTRACT FROM AUTHOR]

We report the formation of a NpIV complex from the complexation of NpVIO22+ with the redox‐active ligand tBu‐pdiop2−=2,6‐bis[N‐(3,5‐di‐tert‐butyl‐2‐hydroxyphenyl)iminomethyl]pyridine. To the best of our knowledge, this is the first example of the direct complexation‐induced chemical reduction of NpVIO22+ to NpIV. In contrast, the complexation of UVIO22+ with tBu‐pdiop2− did not induce the reduction of UVIO22+, not even after the two‐electron electrochemical reduction of [UVIO2(tBu‐pdiop)]. This contrast between the Np and U systems may be ascribed to the decrease of the energy of the 5 f orbitals in Np compared to those in U. The present findings indicate that the redox chemistry between UVIO22+ and NpVIO22+ should be clearly differentiated in redox‐active ligand systems. [ABSTRACT FROM AUTHOR]

Triazolo[4,3-a]pyrimidine is one of the promising structural fragments for the development of drugs, including anticancer drugs. This work is devoted to the synthesis of a number of new 2-arylhydrazone derivatives of thiazolo[3,2-a]pyrimidine, which are synthetic precursors for triazolo[4,3-a]pyrimidines. The crystal structure of 6-acetyl-7-methyl-5-phenyl-2-(2-phenylhydrazineylidene)-5H-thiazolo[3,2-a]pyrimidin-3(2H)-one was established by SCXRD. In the reduction reaction of the compound, the following system was used: vanadium(V) oxide, and sodium borohydride in ethanol at room temperature, which led to the formation of only one pair of diastereomers (1R*)-1-((5S*,6R*,7R*)-(1-(hydroxymethyl)-7-methyl-1,5-diphenyl-1,5,6,7-tetrahydro[1,2,4]triazolo[4,3-a]pyrimidin-6-yl)ethan-1-ol. [ABSTRACT FROM AUTHOR]

The Birch reduction of biaryls generally converts one of the two arenes into a cyclohexa-1,4-diene. Biaryls are more reactive than monocyclic arenes under the Birch conditions. Unlike the reduction of monocyclic arenes, biaryl reduction proceeds through two consecutive electron transfer steps before the protonation of the dianion intermediate. The biaryl reductions and subsequent alkylations in one pot rapidly increase the molecular complexity and thus have been used in the synthesis of natural products and drug-like molecules. 1 Introduction 2 The Physical Organic Chemistry of the Birch Reduction of Biaryls 3 Biaryls as the Mediators of Electron Transfer 4 Methods for the Dissolving-Metal Reduction of Biaryls 5 Intercepting the Biaryl Reduction Intermediates with Electrophiles 6 Synthetic Applications of the Dissolving-Metal-Mediated Reductions of Biaryls 7 Outlook [ABSTRACT FROM AUTHOR]

Technetium‐99 is a prevalent fission product from nuclear waste. The long half‐life (211,000 yr) and environmental mobility of pertechnetate (TcO4−) render Tc particularly challenging to isolate and stabilize. Here we present two approaches for development of potential wasteforms using titanium dioxide, TiO2. Approach 1 is a low temperature chemical synthesis of TiO2 doped with Tc(IV) from TcO4− intended to mimic the Tc waste stream from the UREX family of separations and removes 98.5 % of the Tc, mainly present as edge‐shared Tc(IV) pairs. Approach 2 utilizes TiO2 to photocatalytically reduce TcO4− to Tc(IV) stabilized on the surface of or within the TiO2 lattice. The %Tc removed from solution and adsorbed to TiO2 is pH dependent, with the maximum Tc(IV) adsorbed at pH 3–4 as either TcO2 or edge‐sharing Tc(IV) octahedra. The Tc(IV)‐TiO2 composites materials formed by both approaches are suitable for consolidation into a dense wasteform by Hot Isostatic Pressing (HIPing). [ABSTRACT FROM AUTHOR]

The article presents data on the synthesis and antimicrobial properties of guanidine-containing carboxymethylcellulose derivatives with different physical and chemical characteristics. The regularities of the reaction of nucleophilic substitution of the aldehyde groups of modified Na-carboxymethylcellulose (Na-CMC) by guanidine under different conditions have been studied. It has been found that the maximal replacement of reactive electrophilic groups by nucleophilic reagent depends on the pH value of the medium, molar ratio of guanidine, and the degree of oxidation of cellulose ester. The azomethine derivatives with different content of nitrogen-containing fragments in the polymer chain have been synthesized by varying the reaction conditions and the number of aldehyde groups in oxidized Na-CMC. Chemical reduction of labile azomethine bonds has led to water-soluble derivatives that contain strong amino-bound guanidine groups. The study shows and substantiates the influence of structural parameters (degree of substitution, quantitative guanidine content, pKα values, and nature of counterions) of macromolecular systems on antibacterial and antifungal properties. The developed approach to the synthesis opens up prospects for the creation of antimicrobial derivatives with regulated physical and chemical characteristics and specified biologically active properties. [ABSTRACT FROM AUTHOR]

MXenes, such as Ti 3 C 2 T x , demonstrate tremendous potential as heavy metal adsorbents due to their abundant reaction sites, high hydrophilicity, controllable interlayer spacing, and inherent reduction ability. However, their structural dependent pollutant removal performances and the related mechanisms are far less studied. Therefore, the removing abilities of Cr(VI) from water on Ti 3 C 2 T x MXenes with different structures (multilayer (ML-) and delaminated (DL-) Ti 3 C 2 T x) synthesized via several etching techniques were evaluated. Focusing on the most effective ML- and DL-Ti 3 C 2 T x obtained by acid/fluoride salt etching, the impacts of structural variations on the Cr(VI) removal performances were explored. Both ML- and DL-Ti 3 C 2 T x demonstrate outstanding Cr(VI) adsorption and reduction capabilities, achieving equilibrium within 500 min with capacities of 92.7 and 205 mg/g, respectively. The differences in removal mechanisms stemed from the varying adsorption and reduction capacities of two MXenes. ML-Ti 3 C 2 T x , with lower surface area and porosity, had low adsorption capacity but superior reduction ability, efficiently converting most Cr(VI) to Cr(III) (66.8%). Conversely, DL-Ti 3 C 2 T x exhibited better removal efficiency but a lower capacity for reduction (45.7%). Notably, although the partial reduction of DL-Ti 3 C 2 T x to TiO 2 results in its limited chemical reduction capacity, Ti 3 C 2 T x might serve as a co-catalyst for TiO 2 , boosting the photoresponsiveness of DL-Ti 3 C 2 T x or TiO 2 through Ti 3 C 2 T x /TiO 2 heterojunctions, thereby facilitating photocatalysis to realize the reduction of Cr(VI). Both Ti 3 C 2 T x exhibited both excellent Cr(VI) removal capacity and detoxification capacity, demonstrating their high potential in treating heavy metal pollutants in wastewater. [Display omitted] • Acid/fluoride salt etching produced Ti 3 C 2 T x with the highest Cr(VI) adsorption capacity. • The presence of TiO 2 enhanced the adsorption-photoreduction of Cr(VI) by DL-Ti 3 C 2 T x. • ML-Ti 3 C 2 T x reduced most adsorbed Cr(VI) to Cr(III) via inherent reduction capacity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Trithiocyanuric-linked covalent triazine frameworks are fabricated via facile condensation reaction. • The fabricated TTC-CTFs enabled photo-enhanced precious metal recovery. • TTC-CTFs were competent for continuous flow-through gold recovery from e-waste leachate. • Recovery mechanism was systematically investigated. Precious metals recovery from secondary resources is crucial for ensuring the sustainable supply of resources and development of circular economy. Herein, the trithiocyanuric-linked covalent triazine frameworks (denoted as TTC-CTFs) are proposed and constructed for efficient recovery of precious metals. As expected, the proposed TTC-CTFs afford ultrahigh uptake capacities of 3365 mg g−1 for Au(III) and 1125 mg g−1 for Pt(IV) under light irradiation, achieving the respective 2.3-fold and 1.5-fold enhancement relative to those in the dark and outperforming the previously reported materials. Meanwhile, fast kinetics and superior recyclability are achieved, as reflecting by 15 min of the equilibrium time and neglect decline in recovery efficiency during ten cycles. Post-recovery characterizations and theoretical calculations reveal the combination of adsorption, photoreduction/chemical reduction, and crystallization is responsible for the photo-enhanced Au recovery. Significantly, TTC-CTFs are also competent for selective and efficient gold recovery from the computer processing unit (CPU) leachate, as companied by 99% of recovery efficiency and considerable profit, highlighting the feasibility of the proposed TTC-CTFs for the precious metal recovery from the actual e-waste. [ABSTRACT FROM AUTHOR]

This work reports on the fabrication of a novel planar reduced graphene oxide (rGO) memristor (MR) device. For the first time in the literature, the MR tunable resistive switching behavior is controlled by the GO reduction time at a constant temperature. The device is fabricated using standard microfabrication techniques on a flexible cyclic olefin copolymer substrate (COC). Thermal reduction of the GO layer at low temperatures (100 °C) avoids the drawbacks of chemical reduction methods such as toxicity and electrode metal damage during fabrication, while allowing for fine-tuning of the MR's switching behavior. The device has analog switching characteristics, with a range of different resistance states. By taking advantage of the slow nature of GO thermal annealing, the switching properties of the rGO memristors can be precisely controlled by adjusting the reduction period. At short annealing times (i.e., T < 20 h), the devices switch from high to low resistance states, while at longer annealing times the switching behavior is reversed, with the device switching from low to high resistance states (LRS to HRS). Resistive switching occurs as a result of the diffusion and removal of the oxygen functional groups in the GO film caused by Joule heating induced by the electric current. Complete electrical characterization tests are presented along with wettability and X-ray diffraction (XRD) tests. This work opens a new vision for realizing rGO-based MR devices with tunable switching properties, broadening the application horizon of the device. [ABSTRACT FROM AUTHOR]

The present research focuses on the synthesis of high-purity nickel powder through solution-based chemical reduction using hydrazine hydrate as a reducing agent. A series of synthesis experiments were carried out with variations in the concentration ratio of hydrazine to nickel ions ([N 2 H 4 ]/[Ni2+] = 5–15), the concentration ratio of hydroxyl ions to nickel ions ([OH−]/[Ni2+] = 10–20), temperature (T = 60–80 °C), and reaction time (t = 30–90 min). The Taguchi L9 design of experiments and analysis of variance (ANOVA) was used to identify the role of the hydroxyl-to-nickel ion ratio ([OH⁻]/[Ni2⁺]) in determining the apparent purity of the nickel powder. The highest apparent nickel powder content, which was 92.75 %, was obtained in the experiment with [N 2 H 4 ]/[Ni2+] = 5, [OH−]/[Ni2+] = 12.5, T = 60 °C, and t = 30 min. The optimum conditions that significantly influence the apparent purity of nickel powder derived from data processing are used as the basis for the second stage of the experiment to determine the effect of the [OH−]/[Ni2+] ratio on particle size, morphology, and purity of the synthesized nickel powder. It was found that higher hydroxyl concentrations lead to finer particles, and the morphology of nickel particles is linked to their apparent purity, with the chain of beads of nanoparticle aggregates morphology achievable when [OH−]/[Ni2+] = 12.5 and [OH−]/[Ni2+] = 15. The presented results may contribute to filling the gap in the knowledge to synthesize high-purity nickel powder with controlled size and morphology, which can be used in various applications such as catalysts, conductive fillers, and advanced electrodes. • High-purity Ni powder was succesfully synthesized via a solution-based chemical reduction using hydrazine hydrate. • Higher hydroxyl concentrations produce finer particle sizes. • The particle morphology is related to its purity. • Nanoparticle aggregates morphology achievable at [OH−]/[Ni2+] = 12.5 and [OH−]/[Ni2+] = 15. [ABSTRACT FROM AUTHOR]

Lanthanide (Ln) metals are strong reducing agents (E0(Ln3+/Ln0)≈−2.3 V vs. NHE) which can be applied in various manners in organic synthesis. While samarium and ytterbium have been employed for more than 50 years, the last 20 years have seen the emergence of synthetic applications using other metals, such as lanthanum, cerium, praseodymium, neodymium or dysprosium. The large electron reservoir of lanthanide metals, the Lewis acidic character of the Ln3+ ions and their intermediate electronegativity compared to lithium or magnesium can provide unique reactivity patterns. This review provides an overview on the potential of these metals for synthetic organic chemistry in the following areas: 1) for Grignard type reactivity and radical generation, 2) in reduction chemistry involving carbonyl compounds and dehalogenation reactions and 3) in combination with transition metals. [ABSTRACT FROM AUTHOR]

The article presents the results of scientific research on the method of performing thermophysical calculation of a plasma chemical reactor of a new type which is used for the hydrogen reduction of tungsten and molybdenum oxides. Dependence of geometric dimensions of the reactor chamber of new type plasma chemical reactor on the parameters of the jet flow is given in the article. [ABSTRACT FROM AUTHOR]

In this study, the reduced graphene hydrogel rGH with three-dimensional structure was prepared by chemical reduction method, that the adsorption and removal performance of heavy metal Cr (VI) in water was discussed. Graphene hydrogel is capable of high specific surface area, three-dimensional structure and narrow pore size distribution. Moreover, there are a large number of oxygen-containing functional groups such as hydroxyl groups on the surface of the material. Graphene hydrogel can remove Cr (VI) in water efficiently and continuously, and the removal of Cr (VI) in 1 ppm can keep over 99.5% in 6 hours, indicating the excellent application. [ABSTRACT FROM AUTHOR]

The association between cyclodextrins (CDs) and silver nanoparticles (AgNPs) has been successfully exploited in a large number of applications. Generally, CDs act as stabilizers, however, their reactivity as reducing agents can be directly involved in the synthesis of AgNPs. Herein, the most recent results regarding AgNPs prepared by chemical reduction from native α-, β- and γ-cyclodextrins are reported. The behavior of CDs in host-guest inclusion complexes onto the metal surface, and the effects on the AgNPs properties have also been examined. Unlike β-CD/AgNPs and γ-CD/AgNPs, additional reducing agents were required for the investigated α-CD/AgNPs. [ABSTRACT FROM AUTHOR]

Reduction chemistry induced by divalent lanthanides has been primarily focused on samarium so far. In light of the rich physical properties of the lanthanides, this limitation to one element is a drawback. Since molecular divalent compounds of almost all lanthanides have been available for some time, we used one known and two new non‐classical reducing agents of the early lanthanides to establish a sophisticated reduction chemistry. As a result, six new d/f‐polyphosphides or d/f‐polyarsenides, [K(18‐crown‐6)] [Cp′′2Ln(E5)FeCp*] (Ln=La, Ce, Nd; E=P, As) were obtained. Their reactivity was studied by activation of P4, resulting in a selective expansion of the P5 rings. The obtained compounds [K(18‐crown‐6)] [Cp′′2Ln(P7)FeCp*] (Ln=La, Nd) are the first examples of an activation of P4 by a f‐element‐polypnictide complex. Additionally, the first systematic femtosecond (fs)‐spectroscopy investigations of d/f‐polypnictides are presented to showcase the advantages of having access to a broader series of lanthanide compounds. [ABSTRACT FROM AUTHOR]

The chemical reduction of a π‐expanded polycyclic framework comprising a cyclooctatetraene moiety, octaphenyltetrabenzocyclooctatetraene, with lithium metal readily affords the corresponding tetra‐anion instead of the expected aromatic dianion. As revealed by X‐ray crystallography, the highly contorted tetra‐anion is stabilized by coordination of two internally bound Li+, while two external cations remain solvent separated. The variable‐temperature 7Li NMR spectra in THF confirm the presence of three types of Li+ ions and clearly differentiate internal binding, consistent with the crystal structure. Density‐functional theory calculations suggest that the formation of the highly charged tetra‐reduced carbanion is stabilized through Li+ coordination under the applied experimental conditions. [ABSTRACT FROM AUTHOR]

Hexavalent chromium has been widely distributed in the environment by natural and anthropogenic sources characterized by higher toxicological and solubility properties than the trivalent form. Remediation-by-reduction of chromium (VI) to chromium (III) through the use of chemicals has offered an environmental and cost-effective approach for chromate detoxification. One of the major disadvantages of chemical reduction is that the addition of reductant constitutes a secondary source of contamination; for instance, sodium dithionite at low pH can decompose to sulfur dioxide which can irritate the skin and respiratory tract. In this review, the application of safer reductants of conventional and nanotechnological approaches is addressed. The use of antioxidant biomaterials for chromium (VI) remediation may offer benign alternatives to the use of chemical reductants. [ABSTRACT FROM AUTHOR]

The reduction chemistry of the newly emerging 2‐phosphaethynolate (OCP)− is not well explored, and many unanswered questions remain about this ligand in this context. We report that reduction of [Th(TrenTIPS)(OCP)] (2, TrenTIPS=[N(CH2CH2NSiPri3)]3−), with RbC8 via [2+2+1] cycloaddition, produces an unprecedented hexathorium complex [{Th(TrenTIPS)}6(μ‐OC2P3)2(μ‐OC2P3H)2Rb4] (5) featuring four five‐membered [C2P3] phosphorus heterocycles, which can be converted to a rare oxo complex [{Th(TrenTIPS)(μ‐ORb)}2] (6) and the known cyclometallated complex [Th{N(CH2CH2NSiPri3)2(CH2CH2SiPri2CHMeCH2)}] (4) by thermolysis; thereby, providing an unprecedented example of reductive cycloaddition reactivity in the chemistry of 2‐phosphaethynolate. This has permitted us to isolate intermediates that might normally remain unseen. We have debunked an erroneous assumption of a concerted fragmentation process for (OCP)−, rather than cycloaddition products that then decompose with [Th(TrenTIPS)O]− essentially acting as a protecting then leaving group. In contrast, when KC8 or CsC8 were used the phosphinidiide C−H bond activation product [{Th(TrenTIPS)}Th{N(CH2CH2NSiPri3)2[CH2CH2SiPri2CH(Me)CH2C(O)μ‐P]}] (3) and the oxo complex [{Th(TrenTIPS)(μ‐OCs)}2] (7) were isolated. [ABSTRACT FROM AUTHOR]

To assess the risk of failure of various components in solid oxide cell (SOC) stacks, the temporal evolution of stresses from sintering and thermal gradients in the operating stacks must be known. In this work it is shown experimentally that the residual stresses in a solid oxide cell are relaxed and, in most cases, go to zero at the point of chemical reduction of the structurally dominant fuel electrode from NiO-YSZ to Ni-YSZ. This is essential for understanding and modeling the stresses during the SOC stack assembly and after. In part I, the in-plane macro-strain and stresses in each layer is determined by in-situ X-ray diffraction at different temperatures and during the chemical reduction. The stresses are also analyzed by a multilayer model of the cell. The relaxation of stresses is explained and attributed to so-called accelerated creep occurring in the nickel phase of fuel electrode. • Stress relaxation in solid oxide cells measured in-situ during reduction of Ni(O). • Relaxation results in practically zero stress in cells after stack assembly. • Explained by chemo-thermo-mechanical accelerated creep. • Provides the initial condition for thermo-mechanical models. [ABSTRACT FROM AUTHOR]

Recently, our group employed surface fine crevice structures produced on Cu metal substrates using either laser irradiation or the reduction-sintering of oxide powders to induce region-selective super-spread wetting as a means of joining these substrates. The present work expanded the scope of this method by joining Cu and Fe substrates. Laser irradiation was found to permit the joining of Cu and Fe but generated voids at the join interface. In contrast, the reduction-sintering of mixed oxide powders allowed joining with essentially no voids. Thus, the latter technique is superior to laser irradiation when joining dissimilar metals. [ABSTRACT FROM AUTHOR]

Lanthanide triflates have been used to incorporate NdIII and SmIII ions into the 2.2.2‐cryptand ligand (crypt) to explore their reductive chemistry. The Ln(OTf)3 complexes (Ln=Nd, Sm; OTf=SO3CF3) react with crypt in THF to form the THF‐soluble complexes [LnIII(crypt)(OTf)2][OTf] with two triflates bound to the metal encapsulated in the crypt. Reduction of these LnIII‐in‐crypt complexes using KC8 in THF forms the neutral LnII‐in‐crypt triflate complexes [LnII(crypt)(OTf)2]. DFT calculations on [NdII(crypt)]2+], the first NdII cryptand complex, assign a 4f4 electron configuration to this ion. [ABSTRACT FROM AUTHOR]

In this review, the versatile and rich chemistry for the electrochemical reduction of substrates involving N−O bonds is surveyed. By the cathodic treatment of nitro, nitroso and other oxygenated organic nitrogen substrates, versatile and reactive intermediates are formed which can be subsequently converted to high value‐added products. In many examples, nitrogen heterocycles are selectively formed, but, also depending on the electrolytic conditions, free oximes, nitrones, amines and other entities can be obtained as well. The recent decades have witnessed two major advances – (i) going directly to more complex target molecules and (ii) conducting the electrolyses in much simpler set‐ups. Both improvements make the cathodic access of the target compounds much more practical and scalable. [ABSTRACT FROM AUTHOR]

The Ψ[CH2NH] reduced amide bond is a peptide isostere widely used in the development of bioactive pseudopeptides. Reported here is a method of chemoenzymatic posttranslational modification for the synthesis of Ψ[CH2NH]‐containing peptides converted from ribosomally expressed peptides. The posttranslational conversion composed of an enzymatic cyclodehydration and facile two‐step chemical reduction achieves deoxygenation of a specific amide bond present in a nonprotected peptide in water. This method generates the Ψ[CH2NH] bond in peptides and is applicable to various peptide sequences, potentially enabling the preparation of a library of Ψ[CH2NH]‐containing peptides. [ABSTRACT FROM AUTHOR]

Manganese mainly exists in the form of MnO2 in low grade pyrolusite. Reductant is necessary for leaching manganese from MnO2 ore. Reductant include organic substance and inorganic substance, and leaching process has organic reduction leaching and inorganic reduction leaching. Research progress on reductive leaching of low grade pyrolusite using inorganic substance such as simple substances, compound and roasting as reductant are reviewed at home and abroad. The current problems are pointed out and the recommendations are offered. [ABSTRACT FROM AUTHOR]

In this study, nZVI/LDH composites were prepared by loading nano zero-valent iron (nZVI) on layered double hydroxide (LDH) surface for adsorption coupled reduction of nitrate (NO 3 --N). The results showed that the removal of NO 3 --N and total nitrogen (TN) by the nZVI/LDH composites was 88.64% and 77.63%, respectively, with a selectivity of 55.21% for N 2 and only 1.86% for ammonia nitrogen (NH 4 +-N) within 180 min. The valence states of various N forms during the adsorption-reduction process were investigated. The mechanism of synergistic adsorption-reduction degradation of NO 3 --N was proposed by measuring the contents of NO 3 --N, nitrite (NO 2 --N), and NH 4 +-N in the aqueous and adsorbed phases in the reaction process, including rapid adsorption of initial NO 3 --N, chemical reduction of adsorbed NO 3 --N and resorption of the final product. The nZVI/LDH also maintained up to 82.56% NO 3 --N removal in natural water, with aging experiments proved that the composites maintained 60.48% NO 3 --N removal after 15 days. Therefore, the composites may have great application prospects for NO 3 --N removal in micro-polluted water. [Display omitted] • The nZVI/LDH composites was synthesized for removal of nitrate in micro-polluted water. • nZVI/LDH improved nitrogen selectivity and removed total nitrogen simultaneously. • The mechanism of synergistic adsorption-reduction removal of nitrate was proposed. • The nZVI/LDH composites showed stable and efficient performance in real water. [ABSTRACT FROM AUTHOR]

• BiOBr@H 3 PW 12 O 40 @BiOI is prepared for the first time by simple solvothermal strategy. • S BET and photon trapping ability of BiOBr@BiOI are improved by loading H 3 PW 12 O 40. • W 5d electron orbitals improve the photogenerated electron transmission efficiency. • Photocatalytic redox mechanism is discussed based on the macro-thermodynamic model. In this paper, BiOBr@H 3 PW 12 O 40 @BiOI heterostructure with honeycomb-like morphology is successfully constructed for the first time by a simple one-step solvothermal strategy. The introduction of H 3 PW 12 O 40 effectively improves the specific surface area and photon trapping ability of BiOBr@BiOI heterostructure. More importantly, the W 5d electron orbital of H 3 PW 12 O 40 , as an electron bridge, effectively improves the transmission efficiency of photogenerated electrons in the BiOBr@BiOI heterostructure, thus making the BiOBr@H 3 PW 12 O 40 @BiOI heterostructure show excellent performance in the photocatalytic oxidation or reduction reaction. Based on the macro-thermodynamic model proposed in our previous work and the active species capture experiments, the photocatalytic oxidation or reduction mechanism by using as-prepared BiOBr@H 3 PW 12 O 40 @BiOI heterostructure is discussed in detail. [Display omitted] [ABSTRACT FROM AUTHOR]

The design and synthesis of uranium sorbent materials with high uptake efficiency, capacity and selectivity, as well as excellent hydrolytic stability and radiation resistance remains a challenge. Herein, a polyoxometalate (POM)–organic framework material (SCU‐19) with a rare inclined polycatenation structure was designed, synthesized through a solvothermal method, and tested for uranium separation. Under dark conditions, SCU‐19 can efficiently capture uranium through ligand complexation using its exposed oxo atoms and partial chemical reduction from UVI to UIV by the low‐valent Mo atoms in the POM. An additional UVI photocatalytic reduction mechanism can occur under visible light irradiation, leading to a higher uranium removal without saturation and faster sorption kinetics. SCU‐19 is the only uranium sorbent material with three distinct sorption mechanisms, as further demonstrated by X‐ray photoelectron spectroscopy (XPS) and X‐ray absorption near edge structure (XANES) analysis. [ABSTRACT FROM AUTHOR]

Lindane (γ-hexachlorocyclohexane) and its isomers (HCH) are some of the most common and most easily detected organochlorine pesticides in the environment. The widespread distribution of lindane is due to its use as an insecticide, accompanied by its persistence and bioaccumulation, whereas HCH were disposed of as waste in unmanaged landfills. Unfortunately, certain HCH (especially the most reactive ones: γ- and α-HCH) are harmful to the central nervous system and to reproductive and endocrine systems, therefore development of suitable remediation methods is needed to remove them from contaminated soil and water. This paper provides a short history of the use of lindane and a description of the properties of HCH, as well as their determination methods. The main focus of the paper, however, is a review of oxidative and reductive treatment methods. Although these methods of HCH remediation are popular, there are no review papers summarising their principles, history, advantages and disadvantages. Furthermore, recent advances in the chemical treatment of HCH are discussed and risks concerning these processes are given. Image 1 • Chemical degradation methods for HCH were critically reviewed. • Determination of HCH and related transformation products was reviewed. • First comparison of oxidative and reductive mechanism of HCH was made. • Remedial agents mainly react with HCH by dihalo-, β- and oxidative-elimination. • Discussion concerning risks related to both treatments was made. [ABSTRACT FROM AUTHOR]

Fragrance and flavor industries could not imagine business without aldehydes. Processes for their commercial production raise environmental and ecological concerns. The chemical reduction of organic acids to aldehydes is challenging. To fulfill the demand of a mild and selective reduction of carboxylic acids to aldehydes, carboxylic acid reductases (CARs) are gaining importance. We identified two new subtype IV fungal CARs from Dichomitus squalens CAR (DsCAR) and Trametes versicolor CAR (Tv2CAR) in addition to literature known Trametes versicolor CAR (TvCAR). Expression levels were improved by the co‐expression of GroEL‐GroES with either the trigger factor or the DnaJ‐DnaK‐GrpE system. Investigation of the substrate scope of the three enzymes revealed overlapping substrate‐specificities. Tv2CAR and DsCAR showed a preferred pH range of 7.0 to 8.0 in bicine buffer. TvCAR showed highest activity at pH 6.5 to 7.5 in MES buffer and slightly reduced activity at pH 6.0 or 8.0. TvCAR appeared to tolerate a wider pH range without significant loss of activity. Type IV fungal CARs optimal temperature was in the range of 25–35 °C. TvCAR showed a melting temperature (Tm) of 55 °C indicating higher stability compared to type III and the other type IV fungal CARs (Tm 51–52 °C). Finally, TvCAR was used as the key enzyme for the bioreduction of 3,4‐dihydroxyphenylacetic acid to the antioxidant 3‐hydroxytyrosol (3‐HT) and gave 58 mM of 3‐HT after 24 h, which correlates to a productivity of 0.37 g L−1 h−1. [ABSTRACT FROM AUTHOR]

• Recovery of Y(III) and Eu(III) from waste phosphor powder is studied using leaching, SX and chemical reduction. • 0.1 M D2EHPA is found to be the best among three types of extractants studied with separation factor of 60.6. • Precipitation stripping is used to recover yttrium as oxalate from the loaded organic containing 2.83 g/L Y and 0.06 g/L Eu. • Zinc metal can reduce 78% of Eu(III) to Eu(II). • A flow-sheet is developed for the whole process. This paper deals with the recovery of yttrium and europium from waste tube light phosphor powder leach liquor using solvent extraction and chemical reduction route. Hydrochloric acid (2 mol/L) is used as the leachant to generate the leach liquor. From the leach liquor, the separation of Y(III) and Eu(III) is carried out with three types of extractants (acidic, neutral and ionic liquid) with extractant concentration and pH variation. Highest separation factor of 60.6 is achieved with 0.1 mol/L D2EHPA at aqueous phase pH of 2.56. The quantitative extraction of yttrium from the leach liquor is achieved in two counter current stages at O:A ratio of 1:1.5 at pH 2.56. After extraction of yttrium, yttrium oxalate is prepared by precipitation stripping with 0.4 mol/L oxalic acid. The stability and reusability of the extractant is also investigated. The reduction process with zinc helps to reduce 78% of Eu (III) to Eu (II) but 16% Y(III) is precipitated as yttrium sulfate along with Eu(II) precipitation. A tentative flow-sheet is developed for the whole process. [ABSTRACT FROM AUTHOR]

A novel carbonaceous material (NCM), prepared by the pyrolyzation of the oily sludge of tank bottom, was proposed to remove Cr(VI) from a synthetic solution for the first time. The effects of initial Cr(VI) concentration, NCM dosage and initial solution pH on Cr(VI) removal and the adsorption kinetics, the adsorption isothem were investigated. The removal mechanism was studied by comparing the surface properties of NCM before and after the Cr(VI) removal. The results showed that NCM can effectively remove Cr(Ⅵ) from the synthetic solution with the increase of solution pH at equilibrium. At the initial Cr(Ⅵ) concentrations of 40, 100, 150 and 250 mg/L and NCM dosages of 1, 3, 6 and 8 g/L with initial solution pH of 2, the removal efficiency of Cr(VI) was 95.5, 96.8, 95.2 and 81.2%, and the solution pH at equilibrium reached 2.3, 3.5, 5.8 and 7.5, respectively. NCM was suitable for Cr(Ⅵ) removal while the initial Cr(VI) concentration was less than 100 mg/L and initial solution pH was lower than 2.5. Most of Cr(VI) was removed by the reduction of Fe2+ and S2− in NCM to Cr(III) and with the generation of stable FeCr 2 O 4. Some Cr(VI) may be removed by reacting with Fe2+ and Ca2+ to produce CaCrO 4 and FeCrO 4 on the NCM surface. The dissolution of CaAl 2 Si 2 O 8 and CaS in the solution increased the solution pH at equilibrium. NCM has been proved to be a material with dual functions both chemical reduction and adsorption. Image 1 • NCM can effectively remove Cr(Ⅵ) from a synthetic solution and increase solution pH. • NCM is a multifunctional material with chemical conversion of Cr(VI) to Cr(III) and adsorption. • The CaAl 2 Si 2 O 8 and CaS in NCM dissolved can increase the solution pH at equilibrium. • Cr(VI) was mostly removed by generating FeCr 2 O 4 on NCM surface with help of S2− and Fe2+. [ABSTRACT FROM AUTHOR]

Abstract Functional groups of the activated carbon play the major role in metals removal from aqueous solutions and, for this reason, different treatments can be used to modify the adsorbent surface improving the adsorption capacity for a particular pollutant. In this research, oxidation with nitric acid, heating under an inert atmosphere, and ammonia treatment were applied to modify the activated carbon surface. The modified adsorbents were used for the removal of hexavalent chromium (Cr(VI)) from aqueous solutions at different concentrations (10–500 mg L−1), pH 6, and 25 °C. Adsorption mechanisms of Cr(VI) on the activated carbon were proposed based on the surface chemistry, adsorption/reduction, and desorption experiments. Findings demonstrate that acid functional groups of the activated carbon had an important effect on the hexavalent chromium removal. For instance, a high reduction of Cr(VI) to Cr(III) (50%) was obtained by the oxidized adsorbents, whereas the heat treated adsorbents achieved a low reduction (35%), but the ammonia-treated activated carbon achieved the lowest reduction (20%). The heat-treated adsorbent showed the best Cr(VI) adsorption capacity (48 mg g−1), especially at equilibrium Cr(VI) concentration lower than 200 mg L−1, and the fastest adsorption kinetics among the studied adsorbents. Furthermore, the highest Cr(VI) desorption (90%) was achieved with 0.1 N NaOH-NaCl solutions. In summary, an anionic/reduction coupled adsorption mechanism of Cr(VI) seems to be feasible, and the heat-treated activated carbon is an interesting option for sequestering Cr(VI) species from aqueous effluents. Graphical abstract Image 10398 Highlights • Acid functional groups play the major role in the reduction of Cr(VI) to Cr(III). • Heat-treated adsorbent showed the best Cr(VI) adsorption and desorption capacity. • Basic functional groups enhance the adsorption of Cr(VI) species by electrostatic interactions. • Cr(VI) removal is carried out by anionic/reduction coupled adsorption mechanisms. [ABSTRACT FROM AUTHOR]

Highlights • A phosphorus-rich network polymer was prepared by Friedel-Crafts alkylation. • The polymer has a micro-mesoporous structure with a moderature surface area. • The polymer can efficiently support Ru nanoparticles toward catalytic reduction of nitroarenes. Abstract Hypercrosslinked polymers (HCPs) are a class of promising materials for heterogeneous catalysis in recent years due to their superior physicochemical properties. Herein, a phosphorus-rich network polymer was synthesized by anhydrous FeCl 3 promoted Friedel-Crafts alkylation tris(2-thienyl)phosphine and thiophene. Ruthenium (Ru) nanoparticles supported on this polymer was prepared by in-situ reduction method, which exhibits high catalytic activity for catalytic reduction of nitroarenes at room temperature using NaBH 4 as reductant. The catalyst can be readily recovered and reused without obvious loss of catalytic activity. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • MoS 2 -MnFe 2 O 4 was synthesized by hydrothermal method successfully. • MoS 2 -MnFe 2 O 4 exhibited excellent microwave-induced catalytic activity for the reduction of Cr(VI). • A possible mechanism of Cr(VI) reduction was elucidated. • Cr(VI) reduction occurred over the conduction band of MoS 2. • The loading of MoS 2 was beneficial to suppress the recombination of microwave-excited electron-hole pairs. Abstract Microwave-induced catalytic system has been widely used in oxidation of organic pollutants, but no report focuses on heavy metal reduction. To expand the application field of microwave-induced catalytic system, MoS 2 decorated MnFe 2 O 4 was synthesized by hydrothermal method and employed for the reduction of Cr(VI) in microwave-induced catalytic system. The morphologies, chemical compositions, and optical properties of the synthesized catalysts were investigated using SEM, XRD, FT-IR and XPS. The MoS 2 -MnFe 2 O 4 samples exhibited significantly enhanced microwave-catalytic performance for Cr(VI) reduction compared to pristine MoS 2 and MnFe 2 O 4 , among which, the MoS 2 -MnFe 2 O 4 (10 wt%) sample was most suitable for Cr(VI) reduction in aqueous solution. 85.8% of Cr(VI) removal was obtained in 16 min in the present of MoS 2 -MnFe 2 O 4. The effect of catalyst dosage, initial pH and microwave output on Cr(VI) reduction were investigated. Mechanism of Cr(VI) removal was investigated by radical quenching experiments. The enhanced microwave-catalytic activity of MoS 2 -MnFe 2 O 4 may be owing to the fact that MoS 2 can act as an electron acceptor to suppress the recombination of microwave-excited electron-holes. These results showed that microwave-induced catalytic reduction system is promising in Cr(VI) decontamination in aqueous solution. [ABSTRACT FROM AUTHOR]

The dephosphorization of manganese ores and concentrates in a reducing atmosphere is thermodynamically analyzed. It is shown that phosphorus can completely pass to a gas phase in a closed reaction system in a wide temperature range (1273-2073 K) at the amounts of a reducing gas (CO) that exceed the stoichiometric minimum required for reduction reactions. The gaseous products of reduction is found to contain phosphorus in the form of mainly polyatomic "heavy" molecular oxides, which can decrease the real effect of dephosphorization as compared to that obtained by equilibrium calculations because of kinetic factors. A thermodynamic simulation of a flow reaction system shows that almost complete transition of phosphorus to light gaseous substances (PO, P2) is thermodynamically possible at the temperatures that are close to the technological operation temperatures. This transition is provided by the ratio of the rate of formation of volatile phosphorus-containing substances to the rate of their removal from reaction regions. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Recovery of iron values from Indian red mud through different routes. • Conventional beneficiation processes inefficient to recover iron values. • Concentrate with ∼47% grade, 88% recovery at 72% yield is attained in microwave route. • Microwave route better than conventional route and employs lower time and reductant. • Ferrite balls (∼92% iron content with 94% purity) are observed in the microwave route. Abstract This study investigates the recovery of iron values from Indian red mud through different routes. The conventional beneficiation was found futile to recover iron values from the red mud due to complex structure. The carbothermal reduction is carried out in both muffle and microwave furnace using statistical design. The XRD quantitative phase analysis of the magnetic concentrate indicates distinct phase transformation of hematite to ferrite as a function of temperature and in the sequence Fe 2 O 3 → Fe 3 O 4 → FeO → Fe. In microwave furnace, concentrate with ∼47% grade and 88% recovery at a yield of 72% is attained at optimal conditions of 1000 °C, 10 min with 11% C whereas in muffle furnace, optimal conditions of 1000 °C, 50 min reduction time with 16.5% C yields a concentrate ∼49% iron, 87% iron recovery with a yield of 56%. On comparison of carbothermal reduction in muffle and microwave routes, the microwave route provides a significant improvement in iron grade and recovery at comparatively lower levels of time and reductant dosage. Along with enhanced iron grade-recovery, significant ferrite balls of 1 ± 0.5 mm (∼92% iron content with 94% purity) are observed in the microwave route and were handpicked from the product. Nevertheless, the ferrite phase is forming in both the routes, but in microwave route, ferrite balls of appreciable size and purity accounting ∼8–10% of total iron values in the feed are also observed. In addition, the microwave assisted carbothermal reduction offers a faster reduction rate, cleaner processing and relatively economical in terms of energy and reductant consumption. The product obtained is rich in magnetite, wustite and ferrite phase which can be further used in alternate iron making units. [ABSTRACT FROM AUTHOR]

Treatment of p‐cresol and other substituted phenols in aqueous media with Fe as electron donor, an acid as proton provider and a reduction catalyst was carried out as to mimic the treatment of phenolic wastewaters, in a first attempt of a reductive decontamination. From the various combinations tested, best results were obtained with a mixture of 7 mmol Fe, 9 mL 0.8 M H2SO4 and 0.1 g Rh/C. The parent cyclohexanols were obtained quantitatively after only 50 minutes of shaking, at room temperature, at pH ~ 0.1. The effect of weight ratio phenol: reagents as well as the influence of the reaction time were studied. A reaction pathway was also proposed. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 483–488, 2019 [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Facile reduction of imines using PhSiH 3 as reductant and [M(CO) 5 NHC] (M = Cr, Mo, W) as catalysts. • Catalytic reduction of 11 aromatic imines demonstrated. • Electron density on the metal plays a key role in the catalytic activity. • Bis (NHC) substituted metal carbonyl is a better catalyst than a monosubstituted metal carbonyl. Abstract The catalytic activity of a series of metal carbonyls [M(CO) 6 ], and the corresponding NHC substituted [M(CO) 5 (NHC)], (M = Cr, Mo, W) complexes was examined in the reduction of N -benzylideneaniline and acetophenone using silyl hydrides and isopropanol/KOH as reductants. The use of various additives and ultraviolet irradiation to promote the reduction of imines using silyl hydrides as reductants was explored. From a comparison of the reactivity of [Mo(CO) 6 ], [Mo(CO) 5 (NHC)], and [Mo(CO) 4 (bis NHC)] it was inferred that electron density on the metal centre plays a key role in the catalysis. Four of the best catalysts were then tested in the reduction of a variety of imines with different electronic and steric properties. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Methods of reduction based on borane complexes afford to obtain derivatives protected from reoxidization. • Silanes are the most widespread reagents which are used for the reduction of compounds with P O bond. • The catalytic methods for the reduction of phosphine oxides were described. • Organocatalysis in the reduction of phosphine oxides is possible. Abstract The digest is devoted to the most widespread reducing agents which are used for the reduction of tertiary and secondary phosphine oxides, phospholene oxides, phospholane oxides, phosphonates, phosphinates, α- and β-hydroxy and thiomethyl phosphine oxides, α-aminophosphine oxides. Stereoselectivity of reactions is described. Methods of stabilization of phosphines which are prone to re-oxidation by the formation of borane-adduct or metal complexes are considered. [ABSTRACT FROM AUTHOR]

6-Functionalized 7-R-4,7-dihydro[1,2,4]azolo[1,5-a]pyrimidines (R = H or Me) were synthesized by Biginelli-like reaction of formaldehyde or acetaldehyde, aminoazoles, and corresponding β-dicarbonyl precursor. Alkylation of the obtained compounds proceeds smoothly at position 4, while oxidation leads to 7-R-[1,2,4]azolo[1,5-a]pyrimidines formation. 6-Ethoxycarbonyl derivatives could be reduced to the corresponding alcohols by LiAlH4 and hydrolyzed to the acids. [ABSTRACT FROM AUTHOR]

The metal-free reduction of nitroarenes to aniline derivatives was accomplished in a short time by using a benzothiazoline as the hydrogen donor in combination with a Brønsted acid. An enantioselective synthesis of 2-arylquinolines was achieved by using 1-aryl-3-(2-nitrophenyl)propan-1-ones as starting materials and a combination of a benzothiazoline and a chiral phosphoric acid. [ABSTRACT FROM AUTHOR]

The chemical reduction of a [3]cumulene ([3]TrTol) has been explored using alkali metals. Mono‐ and doubly reduced forms of [3]TrTol were isolated as solvent‐separated ion pairs with {Na(18‐crown‐6)THF2}+ and {K(18‐crown‐6)THF2}+ counterions and crystallographically characterized. This allowed analysis of structural parameters of the "naked" anions of [3]TrTol without interference from metal binding. The dianion of [3]TrTol was also isolated as a contact‐ion complex with {Cs(18‐crown‐6)}+ cations, thereby adding the effect of metal coordination to the core. Structural comparisons of anions to the neutral molecule, [3]TrTol, outline monotonic increases in bond‐length alternation (BLA) upon stepwise reduction. The greatest BLA value is found for the contact‐ion complex, which shows an alternating sequence of short and long carbon–carbon bonds, consistent with the structure of an alkyne. In contrast to studies on tetraphenyl[3]cumulene, the cumulenic framework of [3]TrTol remains planar in all the derivatives. Cumulene or alkyne? The reduction of a [3]cumulene using Na and K in the presence of 18‐crown‐6 gives the mono‐ and doubly reduced cumulenes as solvent‐separated ion pairs. The analogous reduction with Cs affords a contact‐ion complex. Crystallographic analysis of all the species shows dramatically increased bond‐length alternation upon reduction, while the cumulenic framework remains essentially planar in all cases. [ABSTRACT FROM AUTHOR]

The development of biomimetic chemistry based on the NAD(P)H with hydrogen gas as terminal reductant is a long‐standing challenge. Through rational design of the chiral and regenerable NAD(P)H analogues based on planar‐chiral ferrocene, a biomimetic asymmetric reduction has been realized using bench‐stable Lewis acids as transfer catalysts. A broad set of alkenes and imines could be reduced with up to 98 % yield and 98 % ee, likely enabled by enzyme‐like cooperative bifunctional activation. This reaction represents the first general biomimetic asymmetric reduction (BMAR) process enabled by chiral and regenerable NAD(P)H analogues. This concept demonstrates catalytic utility of a chiral coenzyme NAD(P)H in asymmetric catalysis. Through rational design of chiral and regenerable NAD(P)H analogues based on planar‐chiral ferrocene, a biomimetic asymmetric reduction has been realized using bench‐stable Lewis acids as transfer catalysts. A broad set of tetrasubstituted alkenes and imines could be reduced with up to 98 % yield and 98 % ee. This protocol represents the first general biomimetic asymmetric reduction process enabled by NAD(P)H analogues. [ABSTRACT FROM AUTHOR]

In contrast to organic cages which are formed by exploiting dynamic covalent chemistry, such as boronic ester cages, imine cages, or disulfide cages, those with a fully carbonaceous backbone are rarer. With the exception of alkyne metathesis based approaches, the vast majority of hydrocarbon cages need to be synthesized by kinetically controlled bond formation. This strategy implies a multiple step synthesis and no correction mechanism in the final macrocyclization step, both of which are responsible for low overall yields. Whereas for smaller cages the intrinsic drawbacks are not always obvious, larger cages are seldom synthesized in yields beyond a few tenths of a percent. Presented herein is a three‐step method to convert imine cages into hydrocarbon cages. The method has been successfully applied to even larger structures such as derivatives of C72H72 , an unknown cage suggested by Fritz Vögtle more than 20 years ago. All‐carbon cages: In just three steps imine cages are converted into hydrocarbon cages by reduction, nitrosylation, and formation of the C−C bonds by an Overberger reaction. The method has been successfully applied to even larger structures, such as derivatives of C72H72. [ABSTRACT FROM AUTHOR]

A new structural class of boron‐based diradicals is prepared by Lewis base addition to and reduction of singly cyclic (alkyl)(amino)carbene (CAAC) stabilised diborylalkenes. The diradicals feature a perpendicular olefinic bridge preventing delocalization between the B(CAAC) π systems, making the coupling between the spin centres very weak. DFT calculations indicate that the compounds are ground‐state (open‐shell) singlets, with triplet states negligibly higher in energy, thus making the triplet states easily populated thermally. B(CAAC) for more: A new structural class of boron‐based diradicals is prepared by Lewis base addition to and reduction of singly CAAC‐stabilised diborylalkenes. The diradicals feature a perpendicular olefinic bridge preventing delocalization between the B(CAAC) π systems, making the coupling between the spin centres very weak. [ABSTRACT FROM AUTHOR]

Abstract: We synthesized the reproducible heterogeneous catalyst of graphene oxide (GO)-supported palladium nanoparticles (NPs) via a simple and green process. The structure, morphology and physicochemical properties of the synthesized heterogeneous catalyst were characterized by the latest techniques such as high-resolution transmission electron microscopy (TEM), scanning TEM, energy-dispersive X-ray spectroscopy, X-ray diffraction analysis, and X-ray photoelectron spectroscopy. The GO-supported Pd NPs (Pd/GO nanocatalyst) exhibited excellent catalytic activity for the reduction of nitroaromatics to aminoaromatics in aqueous sodium borohydride. The nitroaromatics were converted to corresponding aminoaromatics with high yields (up to 99%) using Pd/GO nanocatalyst in aqueous solution. The hybrid heterogeneous catalyst showed 83% of conversion after six cycles in the reduction of nitrobenzene to aminobenzene. These features ensured the high catalytic activity of the introduced graphene oxide supported Pd nanocatalysts.Graphical abstract: [ABSTRACT FROM AUTHOR]

The metal-reducing γ-proteobacterium Shewanella oneidensis reduces iodate (IO3- as anaerobic terminal electron acceptor. Microbial IO3- electron transport pathways are postulated to terminate with nitrate (NO3-) reductase, which reduces IO3- as alternative electron acceptor. Recent studies with S. oneidensis, however, have demonstrated that NO3 reductase is not involved in IO3- reduction. The main objective of the present study was to determine the metal reduction and protein secretion genes required for IO3- reduction by Shewanella oneidensis with lactate, formate, or H2 as electron donors. With all electron donors, the type I and type V protein secretion mutants retained wild-type IO3- reduction activity, while the type II protein secretion mutant lacking the outer membrane secretin GspD was impaired in IO3- reduction. Deletion mutants lacking the cyclic AMP receptor protein CRP, cytochrome maturation permease CcmB, and inner membrane-tethered ctype cytochrome CymA were impaired in IO3- reduction with all electron donors, while deletion mutants lacking c-type cytochrome MtrA and outer membrane β-barrel protein MtrB of the outer membrane MtrAB module were were impaired in IO3- reduction with only lactate as electron donor. With all electron donors, mutants lacking the c-type cytochromes OmcA and MtrC of the metal-reducing extracellular electron conduit MtrCAB retained wild-type IO3- reduction activity. These findings indicate that IO3- reduction by S. oneidensis involves electron donor-dependent metal reduction and protein secretion pathway components, including the outer membrane MtrAB module and type II protein secretion of an unidentified IO3- reductase to the S. oneidensis outer membrane. [ABSTRACT FROM AUTHOR]