Double Nitrogenation Layer Formed Using Nitric Oxide for Enhancing Li+ Storage Performance, Cycling Stability, and Safety of Si Electrodes.

To enhance Li storage properties, nitrogenation methods are developed for Si anodes. First, melamine, urea, and nitric oxide (NO) precursors are used to nitrogenize carbon-coated Si particles. The properties of the obtained particles are compared. It is found that the NO process can maximize the graphitic nitrogen (N) content and electronic conductivity of a sample. In addition, optimized N functional groups and O─C species on the electrode surface increase electrolyte wettability. However, with a carbon barrier layer, NO hardly nitrogenizes the Si cores. Therefore, bare Si particles are reacted with NO. Core-shell Si@amorphous SiNx particles are produced using a facile and scalable NO treatment route. The effects of the NO reaction time on the physicochemical properties and charge-discharge performance of the obtained materials are systematically examined. Finally, the Si@SiNx particles are coated with N-doped carbon. Superior capacities of 2435 and 1280 mAh g-1 are achieved at 0.2 and 5 A g-1, respectively. After 300 cycles, 90% of the initial capacity is retained. In addition, differential scanning calorimetry data indicate that the multiple nitrogenation layers formed by NO significantly suppress electrode exothermic reactions during thermal runaway.

Late-stage modification of bioactive compounds: Improving druggability through efficient molecular editing.

Synthetic chemistry plays an indispensable role in drug discovery, contributing to hit compounds identification, lead compounds optimization, candidate drugs preparation, and so on. As Nobel Prize laureate James Black emphasized, "the most fruitful basis for the discovery of a new drug is to start with an old drug"1. Late-stage modification or functionalization of drugs, natural products and bioactive compounds have garnered significant interest due to its ability to introduce diverse elements into bioactive compounds promptly. Such modifications alter the chemical space and physiochemical properties of these compounds, ultimately influencing their potency and druggability. To enrich a toolbox of chemical modification methods for drug discovery, this review focuses on the incorporation of halogen, oxygen, and nitrogen-the ubiquitous elements in pharmacophore components of the marketed drugs-through late-stage modification in recent two decades, and discusses the state and challenges faced in these fields. We also emphasize that increasing cooperation between chemists and pharmacists may be conducive to the rapid discovery of new activities of the functionalized molecules. Ultimately, we hope this review would serve as a valuable resource, facilitating the application of late-stage modification in the construction of novel molecules and inspiring innovative concepts for designing and building new drugs.

A Catalytic Method to Activate Nitromethane by the Cooperation of Homo- and Heterogeneous Catalysis.

The achievement of directly activating and utilizing bulk small molecules has remained a longstanding objective in the field of chemical synthesis. The present work reports a catalytic activation method for bulk chemical nitromethane (MeNO2 ). This method combines homogeneous Lewis acid with recyclable heterogeneous Brønsted acid catalysis, featuring practicality, sustainability, and low cost, thus solving the inherent drawbacks of previous Nef processes where stoichiometric reductants or activators were required. By combining the advantages of both homo- and heterogeneous catalysts, this chemistry may not only offer new opportunities for the further development of MeNO2 as a nitrogen source for organic synthesis, but also promote the catalysis design in synthetic chemistry.

Nitrogen-Doped CuO@CuS Core-Shell Structure for Highly Efficient Catalytic OER Application.

Water electrolysis is a highly efficient route to produce ideally clean H2 fuel with excellent energy conversion efficiency and high gravimetric energy density, without producing carbon traces, unlike steam methane reforming, and it resolves the issues of environmental contamination via replacing the conventional fossil fuel. Particular importance lies in the advancement of highly effective non-precious catalysts for the oxygen evolution reaction (OER). The electrocatalytic activity of an active catalyst mainly depends on the material conductivity, accessible catalytically active sites, and intrinsic OER reaction kinetics, which can be tuned via introducing N heteroatoms in the catalyst structure. Herein, the efficacious nitrogenation of CuS was accomplished, synthesized using a hydrothermal procedure, and characterized for its electrocatalytic activity towards OER. The nitrogen-doped CuO@CuS (N,CuO@CuS) electrocatalyst exhibited superior OER activity compared to pristine CuS (268 and 602 mV), achieving a low overpotential of 240 and 392 mV at a current density of 10 and 100 mA/cm2, respectively, ascribed to the favorable electronic structural modification triggered by nitrogen incorporation. The N,CuO@CuS also exhibits excellent endurance under varied current rates and a static potential response over 25 h with stability measured at 10 and 100 mA/cm2.

Adsorption of Chromium (VI) Using an Activated Carbon Derived from Petroleum Coke Feedstock.

This study aims to determine the main adsorption mechanism by which chromium (VI) is adsorbed onto the surface of a petroleum-coke sourced activated carbon, a feedstock not prevalent in current literature. The study also aims to produce an activated carbon adsorbent that is both cost-effective and efficient for the removal of chromium (VI) in neutral waters. The efficacy of thermally-treated petroleum coke-activated carbon and nitrogenated petroleum coke-activated carbon using ammonium chloride is compared to the efficacy of commercially available activated carbon. X-ray photoelectron spectroscopy of the activated carbons was obtained both before and after exposure to chromium (VI) for characterization of the materials and confirmation of chromium adsorption. The thermally-treated and nitrogenated activated carbons showed significant enhancement of chromium (VI) removal compared to the non-treated petroleum coke-activated carbon (22.4 mg/g, 21.9 mg/g, and 17.0 mg/g, respectively). However, there was no significant difference observed between the thermally-treated and nitrogenated materials. This indicates that the nitrogenation of the surface does not improve the adsorption capacity of the activated carbon, but rather the thermal treatment itself. X-ray photoelectron spectroscopy showed a significant increase in the alcohol functional groups on the surface of the activated carbon material as a result of the heat-treatment process; from 16.02 atomic percent in the non-treated activated carbon to 26.3 atomic percent in the thermally-treated activated carbon. The alcohol functional groups present on the surface allow for chromium (VI) to undergo reduction to chromium (III) under a similar mechanism to the well-known Jones Oxidation Reaction where the reduced chromium (III) species are then physisorbed to the surface of the activated carbon. XPS results are consistent with this as the chromium species present on the surface of the adsorbent is primarily Cr(OH)3 (85.6% in the standard AC and 82.5% in the thermally-treated AC). Pseudo-first-order and pseudo-second-order kinetic modeling of the adsorbents indicate that they follow a pseudo-second-order reaction where the rate-limiting step is the chemical sorption of the adsorbate itself.

Mechanochemical Synthesis and Nitrogenation of the Nd1.1Fe10CoTi Alloy for Permanent Magnet.

In this work, the mechanochemical synthesis method was used for the first time to produce powders of the nanocrystalline Nd1.1Fe10CoTi compound from Nd2O3, Fe2O3, Co and TiO2. High-energy-milled powders were heat treated at 1000 °C for 10 min to obtain the ThMn12-type structure. Volume fraction of the 1:12 phase was found to be as high as 95.7% with 4.3% of a bcc phase also present. The nitrogenation process of the sample was carried out at 350 °C during 3, 6, 9 and 12 h using a static pressure of 80 kPa of N2. The magnetic properties Mr, µ0Hc, and (BH)max were enhanced after nitrogenation, despite finding some residual nitrogen-free 1:12 phase. The magnetic values of a nitrogenated sample after 3 h were Mr = 75 Am2 kg-1, µ0Hc = 0.500 T and (BH)max = 58 kJ·m-3. Samples were aligned under an applied field of 2 T after washing and were measured in a direction parallel to the applied field. The best value of (BH)max ~ 114 kJ·m-3 was obtained for 3 h and the highest µ0Hc = 0.518 T for 6 h nitrogenation. SEM characterization revealed that the particles have a mean particle size around 360 nm and a rounded shape.

Electrochemical B-H Nitrogenation: Access to Amino Acid and BODIPY-Labeled nido-Carboranes.

Electrocatalyzed oxidative B-H nitrogenations of nido-carborane (nido-7,8-C2 B9 H12- ) with N-heterocycles have been established, enabling the preparation of various N-substituted nido-carboranes without chemical oxidants or metal catalyst under ambient conditions. The electrolysis manifold occurred with high levels of efficiency as well as chemo- and position- selectivity, employing sustainable electricity as the sole oxidant. The strategy set the stage for a user-friendly access to novel amino acid and fluorogenic boron-dipyrrin (BODIPY)-labeled nido-carborane hybrids.

First-Principles Study of Nitrogen Adsorption and Dissociation on PuH2 (111) Surface.

Plutonium mononitride is one of the main fuels for Generation IV reactors and can be prepared from nitrogenation of plutonium hydride. We investigated the adsorption and dissociation of nitrogen on PuH2 (111) surface to elaborate the initial stage of nitrogenation. The adsorption energies varied greatly with respect to the adsorption sites and orientations of the adsorbed molecule. The nitrogen exhibited preferential adsorption above the ccp site, where the molecular nitrogen was nearly parallel to the PuH2 surface and pointed to the nearest Pu atom. The orbital hybridization and the electrostatic attraction between the Pu and N weakened the N-N bond in the adsorbed molecule. The mechanism of the dissociation process was investigated within transition state theory, and the analysis of the activation barrier indicated that dissociation of nitrogen is not the rate-determining step of nitrogenation. These findings can contribute to a better understanding of the nuclear fuel cycle.

Synergistic Effects of Polymer Donor Backbone Fluorination and Nitrogenation Translate into Efficient Non-Fullerene Bulk-Heterojunction Polymer Solar Cells.

State-of-the-art non-fullerene bulk-heterojunction (BHJ) polymer solar cells outperform the more extensively studied polymer-fullerene BHJ solar cells in terms of efficiency, thermal-, and photostability. Considering the strong light absorption in the near-infrared region (600-1000 nm) for most of the efficient acceptors, the exploration of high-performing large band gap (LBG) polymer donors with complementary optical absorption ranging from 400 to 700 nm remains critical. In this work, the strategy of concurrently incorporating fluorine (-F) and unsaturated nitrogen (-N) substituents along the polymer backbones is used to develop the LBG polymer donor PB[N][F]. Results show that the F- and N-substituted polymer donor PB[N][F] realizes up to 14.4% efficiency in BHJ photovoltaic devices when paired with a benchmark molecule acceptor Y6, which largely outperforms the analogues PB with an efficiency of only 3.6% and PB[N] with an efficiency of 11.8%. Systematic examinations show that synergistic effects of polymer backbone fluorination and nitrogenation can significantly increase ionization potential values, improve charge transport, and reduce bimolecular recombination and trap-assisted recombination in the PB[N][F]:Y6 BHJ system. Importantly, our study shows that the F- and N-substituted conjugated polymers are promising electron-donor materials for solution-processed non-fullerene BHJ solar cells.

Nitrogen incorporation in saturated aliphatic C6-C8 hydrocarbons and ethanol in low-pressure nitrogen plasma generated by a hollow cathode discharge ion source.

Ion/molecule reactions of saturated hydrocarbons (n-hexane, cyclohexane, n-heptane, n-octane and isooctane) in 28-Torr N2 plasma generated by a hollow cathode discharge ion source were investigated using an Orbitrap mass spectrometer. It was found that the ions with [M+14](+) were observed as the major ions (M: sample molecule). The exact mass analysis revealed that the ions are nitrogenated molecules, [M+N](+) formed by the reactions of N3 (+) with M. The reaction, N3 (+) + M → [M+N](+) + N2 , were examined by the density functional theory calculations. It was found that N3 (+) abstracts the H atom from hydrocarbon molecules leading to the formation of protonated imines in the forms of R'R″CNH2 (+) (i.e. C-H bond nitrogenation). This result is in accord with the fact that elimination of NH3 is the major channel for MS/MS of [M+N](+) . That is, nitrogen is incorporated in the C-H bonds of saturated hydrocarbons. No nitrogenation was observed for benzene and acetone, which was ascribed to the formation of stable charge-transfer complexes benzene⋅⋅⋅⋅N3 (+) and acetone⋅⋅⋅⋅N3 (+) revealed by density functional theory calculations. Copyright © 2016 John Wiley & Sons, Ltd.

Nitrogenated honokiol derivatives allosterically modulate GABAA receptors and act as strong partial agonists.

In traditional Asian medicinal systems, preparations of the root and stem bark of Magnolia species are widely used to treat anxiety and other nervous disturbances. The biphenyl-type neolignan honokiol together with its isomer magnolol are the main constituents of Magnolia bark extracts. We have previously identified a nitrogen-containing honokiol derivative (3-acetylamino-4'-O-methylhonokiol, AMH) as a high efficient modulator of GABAA receptors. Here we further elucidate the structure-activity relation of a series of nitrogenated biphenyl-neolignan derivatives by analysing allosteric modulation and agonistic effects on α1ß2γ2S GABAA receptors. The strongest IGABA enhancement was induced by compound 5 (3-acetamido-4'-ethoxy-3',5-dipropylbiphenyl-2-ol, Emax: 123.4±9.4% of IGABA-max) and 6 (5'-amino-2-ethoxy-3',5-dipropylbiphenyl-4'-ol, Emax: 117.7±13.5% of IGABA-max). Compound 5 displayed, however, a significantly higher potency (EC50=1.8±1.1 µM) than compound 6 (EC50=20.4±4.3 µM). Honokiol, AMH and four of the derivatives induced significant inward currents in the absence of GABA. Strong partial agonists were honokiol (inducing 78±6% of IGABA-max), AMH (63±6%), 5'-amino-2-O-methylhonokiol (1) (59±1%) and 2-methoxy-5'-nitro-3',5-dipropylbiphenyl-4'-ol (3) (52±1%). 3-N-Acetylamino-4'-ethoxy-3',5-dipropyl-biphenyl-4'-ol (5) and 3-amino-4'-ethoxy-3',5-dipropyl-biphenyl-4'-ol (7) were less efficacious but even more potent (5: EC50=6.9±1.0 µM; 7: EC50=33.2±5.1 µM) than the full agonist GABA.

Functionalization of alkynes by a (salen)ruthenium(VI) nitrido complex.

Exploring new reactivity of metal nitrides is of great interest because it can give insights to N2 fixation chemistry and provide new methods for nitrogenation of organic substrates. In this work, reaction of a (salen)ruthenium(VI) nitrido complex with various alkynes results in the formation of novel (salen)ruthenium(III) imine complexes. Kinetic and computational studies suggest that the reactions go through an initial ruthenium(IV) aziro intermediate, followed by addition of nucleophiles to give the (salen)ruthenium(III) imine complexes. These unprecedented reactions provide a new pathway for nitrogenation of alkynes based on a metal nitride.

Nitrogenation of some eugenol derivatives

Nitro compounds of eugenol were rarely described because eugenol derivatives with OH- and CH2=CH-CH2 groups in the molecular can be easy oxidated and polymerized on nitration reaction. The nitration of eugenol derivatives is an important reaction because the nitro group can be converted into a large variety of other functional groups. Eugenoxy acetic acid its methyl, ethyl esters were treated with HNO3 in CH3COOH to give dinitro eugenoxy acetic acid, methyl dinitro eugenoxy acetate and ethyl dinitro eugenoxy acetate. IR- and UV - spectra show that one nitro group replaces H at benzene ring, the other replaces H at alkyl group.