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The Schmidt reaction has been an efficient and widely used synthetic approach to amides and nitriles since its discovery in 1923. However, its application often entails the use of volatile, potentially explosive, and highly toxic azide reagents. Here, we report a sequence whereby triflic anhydride and formic and acetic acids activate the bulk chemical nitromethane to serve as a nitrogen donor in place of azides in Schmidt-like reactions. This protocol further expands the substrate scope to alkynes and simple alkyl benzenes for the preparation of amides and nitriles.

Solution-based electrical doping protocols may allow more versatility in the design of organic electronic devices; yet, controlling the diffusion of dopants in organic semiconductors and their stability has proven challenging. Here we present a solution-based approach for electrical p-doping of films of donor conjugated organic semiconductors and their blends with acceptors over a limited depth with a decay constant of 10–20 nm by post-process immersion into a polyoxometalate solution (phosphomolybdic acid, PMA) in nitromethane. PMA-doped films show increased electrical conductivity and work function, reduced solubility in the processing solvent, and improved photo-oxidative stability in air. This approach is applicable to a variety of organic semiconductors used in photovoltaics and field-effect transistors. PMA doping over a limited depth of bulk heterojunction polymeric films, in which amine-containing polymers were mixed in the solution used for film formation, enables single-layer organic photovoltaic devices, processed at room temperature, with power conversion efficiencies up to 5.9 ± 0.2% and stable performance on shelf-lifetime studies at 60 °C for at least 280 h. A solution process for the diffusion of dopants in organic semiconducting films over a limited depth has been developed. The method is applied to single polymers and donor–acceptor mixtures, and for the realization of single-layer solar cells.

3,4-Methylenedioxy- β -nitrostyrene (MNS) is an inhibitor of NLRP3 (nucleotide-binding oligomerization domain-like receptor family, pyrin domain-containing 3) inflammasome. This inflammasome is a potential PET imaging target, because it is involved in the aggregation of amyloid- β and tau proteins in Alzheimer’s disease brains. We succeeded in a challenging radio-synthesis of [ 11 C]MNS using nitromethylenating piperonal with [ 11 C]nitromethane (CH 3 NO 2 ) in one pot. We then evaluated this ligand in rat brains. Although [ 11 C]MNS had some moderate brain uptake and quick washout in rat brains, we were unable to detect any presence of specific binding of this ligand to NLRP3 either in vivo or in vitro. Further studies appear needed to develop more suitable radioligands for PET imaging of NLRP3.

Which came first, the chicken or the egg? This age-old riddle is also present for the formation sequence of the surface methoxy species and dimethyl ether in zeolite-catalyzed methanol chemistry due to their inevitable interconversion at high temperatures. The challenge is the lack of feasible reaction conditions to achieve the formation of surface methoxy species by Brønsted acids at mild temperatures. This work proposes a microenvironment design strategy to manipulate the reaction routes inside zeolite channels with the assistance of nitromethane, realizes the surface methoxy species generation catalyzed by Brønsted acids at 363 kelvin, and solves the long-standing problem of the origin and evolution of the highly active surface methoxy species during zeolite Brønsted-acid-catalyzed methanol conversion process. It is found that the surface methoxy species mainly originate from dimethyl ether decomposition under these mild conditions. These findings provide a perspective to subtly manipulate the reaction routes by tailoring the chemical microenvironment, and offer fresh insights into the zeolite-catalyzed methanol chemistry. Deciphering the formation sequence of surface methoxy species (SMS) and dimethyl ether (DME) in zeolite-catalyzed methanol reactions remains a challenge. Here, the authors tackle this issue by employing a microenvironment design strategy to steer reaction pathways within zeolite channels, enabling SMS formation from DME decomposition catalyzed by Brønsted acids at 363 K.

The Kathmandu Valley in Nepal suffers from severe wintertime air pollution. Volatile organic compounds (VOCs) are key constituents of air pollution, though their specific role in the valley is poorly understood due to insufficient data. During the SusKat-ABC (Sustainable Atmosphere for the Kathmandu Valley–Atmospheric Brown Clouds) field campaign conducted in Nepal in the winter of 2012–2013, a comprehensive study was carried out to characterise the chemical composition of ambient Kathmandu air, including the determination of speciated VOCs, by deploying a proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) – the first such deployment in South Asia. In the study, 71 ion peaks (for which measured ambient concentrations exceeded the 2σ detection limit) were detected in the PTR-TOF-MS mass scan data, highlighting the chemical complexity of ambient air in the valley. Of the 71 species, 37 were found to have campaign average concentrations greater than 200 ppt and were identified based on their spectral characteristics, ambient diel profiles and correlation with specific emission tracers as a result of the high mass resolution (m ∕ Δm  >  4200) and temporal resolution (1 min) of the PTR-TOF-MS. The concentration ranking in the average VOC mixing ratios during our wintertime deployment was acetaldehyde (8.8 ppb)  >  methanol (7.4 ppb)  >  acetone + propanal (4.2 ppb)  >  benzene (2.7 ppb)  >  toluene (1.5 ppb)  >  isoprene (1.1 ppb)  >  acetonitrile (1.1 ppb)  >  C8-aromatics ( ∼ 1 ppb)  >  furan ( ∼ 0.5 ppb)  >  C9-aromatics (0.4 ppb). Distinct diel profiles were observed for the nominal isobaric compounds isoprene (m ∕ z  =  69.070) and furan (m ∕ z  =  69.033). Comparison with wintertime measurements from several locations elsewhere in the world showed mixing ratios of acetaldehyde ( ∼  9 ppb), acetonitrile ( ∼  1 ppb) and isoprene ( ∼  1 ppb) to be among the highest reported to date. Two \"new\" ambient compounds, namely formamide (m ∕ z  =  46.029) and acetamide (m ∕ z  =  60.051), which can photochemically produce isocyanic acid in the atmosphere, are reported in this study along with nitromethane (a tracer for diesel exhaust), which has only recently been detected in ambient studies. Two distinct periods were selected during the campaign for detailed analysis: the first was associated with high wintertime emissions of biogenic isoprene and the second with elevated levels of ambient acetonitrile, benzene and isocyanic acid from biomass burning activities. Emissions from biomass burning and biomass co-fired brick kilns were found to be the dominant sources for compounds such as propyne, propene, benzene and propanenitrile, which correlated strongly with acetonitrile (r2 > 0.7), a chemical tracer for biomass burning. The calculated total VOC OH reactivity was dominated by acetaldehyde (24.0 %), isoprene (20.2 %) and propene (18.7 %), while oxygenated VOCs and isoprene collectively contributed to more than 68 % of the total ozone production potential. Based on known secondary organic aerosol (SOA) yields and measured ambient concentrations in the Kathmandu Valley, the relative SOA production potential of VOCs were benzene  >  naphthalene  >  toluene  >  xylenes  >  monoterpenes  >  trimethylbenzenes  >  styrene  >  isoprene. The first ambient measurements from any site in South Asia of compounds with significant health effects such as isocyanic acid, formamide, acetamide, naphthalene and nitromethane have been reported in this study. Our results suggest that mitigation of intense wintertime biomass burning activities, in particular point sources such biomass co-fired brick kilns, would be important to reduce the emission and formation of toxic VOCs (such as benzene and isocyanic acid) in the Kathmandu Valley.

A simple green method for synthesizing the substituted pyrroles through one-pot multicomponent reaction of primary amines, 1,3-dicarbonyls, nitromethane and benzaldehyde catalysed by eosin Y under visible light irradiation at room temperature have been developed. The aim of this study is develop a green and cost-effective approach to synthesize substituted pyrroles and its derivatives with high yields in a short reaction time using an organic photocatalyst. Graphical Abstract

In this study, we assess the effectiveness of portable near-infrared (NIR) spectroscopy coupled with advanced machine learning algorithms for on-site detection and quantification of key explosive precursors, in accordance with EU Regulation 2019/1148. The research focuses on developing robust quantitative models for hydrogen peroxide, nitromethane, and nitric acid, addressing the challenge of varied concentrations and compositions encountered by first responders. The models demonstrated high predictive accuracy, with Root Mean Square Error of Prediction (RMSEP) values of 0.96 % for hydrogen peroxide, 2.46 % for nitromethane, and 0.70 % for nitric acid across diverse samples. The qualitative models created for those explosives precursors also showed high effectiveness and reliability, with minimal false negatives and false positives. The integration of machine learning algorithms facilitated the adaptation of these models to handle the complex variability of precursor formulations effectively. Additionally, the utilization of cloud operating systems provided significant advantages for real-time analysis and continuous data updating, essential for maintaining the accuracy and relevance of the models in rapidly changing field conditions. This research highlights the potential of integrating advanced spectroscopic techniques and machine learning within a cloud-based framework to improve the detection and management of explosive precursors in field settings. This integration enables the reliable detection and quantification of these precursors in a matter of seconds. Future work will extend this approach to additional precursors and explore complementary technologies to further enhance on-site detection capabilities. •Portable NIR spectroscopy detects and quantifies explosive precursors.•Machine learning models capture the variability of precursor formulations.•NIR architectures ensures accurate on-site detection and legal compliance.•Cloud-based systems enable real-time updates and decentralized analysis.

The article presents an evaluation of the detonation performance of a nitromethane-ammonium nitrate fuel oil energetic material. The brisance and relative strength of this material were assessed using the Hess and Trauzl methods. Both methods confirmed that the shattering effect and relative work increase in a polynomial manner with the increasing content of nitromethane. A significant enhancement in detonation parameters was observed with up to 9% nitromethane addition. The results from the Trauzl and Hess tests indicated that at 9% nitromethane content, the average cavity expansion and brisance were 371 cm 3 and 10.01 mm, respectively. The improved detonation performance is attributed to the introduction of additional nitro groups from nitromethane, replacing fuel oil, as well as the increased density of the energetic material.

The detection of intact explosives in the field provides a unique challenge for investigators, considering the sensitive and dangerous nature of these samples. Handheld Raman instruments have grown in popularity for the analysis of unknown samples in the field, combining speed of data collection and reliability with a size that allows for the instruments to be field portable. Handheld Raman instruments are used commonly in the field, and yet there is very little research on the detection capabilities of these instruments, specifically for explosive compounds. The present study aimed to evaluate the detection capabilities of two handheld Raman spectrometers, the Rigaku ResQ-CQL and the Field Forensics HandyRam™, using explosives analytical standards, including 2,4,6-trinitrotoluene (TNT), nitromethane (NM), ammonium nitrate (AN) and smokeless powder components such as diphenylamine (DPA), ethyl centralite (EC), and methyl centralite (MC). The spectrometers were evaluated on their sensitivity, the repeatability of the data, and the performance of the internal library when available. In addition, an interference study with glass and plastic containers was also performed. Finally, authentic intact explosive samples, including TNT flakes, a mixture of ammonium nitrate and fuel oil (ANFO), smokeless powder and nitromethane were analyzed to evaluate the developed method and test the detection capabilities of the spectrometers with authentic samples. Spectra were reproducible for all the analytes across both instruments, with regards to the peak location and the intensity. Spectra obtained with the Rigaku ResQ-CQL displayed better resolution for all analytes, including the authentic samples. In addition, its wider scan range allowed for the detection of more detailed peaks below 400 cm−1. Identifying the detection capabilities of these handheld instruments can therefore help guide investigators on how to best utilize them in the field. [Display omitted] •Peak location and intensity of spectra were reproducible for all analytes with both spectrometers.•Rigaku ResQ-CQL showed low fluorescence and better resolution across all analytes.•Primary limitation identified of handheld spectrometers was relatively high limits of detection.•All analytes could be detected in glass and plastic containers with both spectrometers.

Nitroalkanes such as nitromethane, nitroethane, 1-nitropropane (1NP), and 2-nitropropane (2NP), derived from anthropogenic activities, are hazardous environmental pollutants due to their toxicity and carcinogenic activity. In nature, 3-nitropropionate (3NPA) and its derivatives are produced as a defense mechanism by many groups of organisms, including bacteria, fungi, insects, and plants. 3NPA is highly toxic as its conjugate base, propionate-3-nitronate (P3N), is a potent inhibitor of mitochondrial succinate dehydrogenase, essential to the tricarboxylic acid cycle, and can inhibit isocitrate lyase, a critical enzyme of the glyoxylate cycle. In response to these toxic compounds, several organisms on the phylogenetic scale express genes that code for enzymes involved in the catabolism of nitroalkanes: nitroalkane oxidases (NAOs) and nitronate monooxygenases (NMOs) (previously classified as nitropropane dioxygenases, NPDs). Two types of NMOs have been identified: class I and class II, which differ in structure, catalytic efficiency, and preferred substrates. This review focuses on the biochemical properties, structure, classification, and physiological functions of NMOs, and offers perspectives for their in vivo and in vitro applications.Key points• Nitronate monooxygenases (NMOs) are key enzymes in nitroalkane catabolism.• NMO enzymes are involved in defense mechanisms in different organisms.• NMO applications include organic synthesis, biocatalysts, and bioremediation.