Source Of Radicals Research Articles

Unlocking carbene reactivity by metallaphotoredox α-elimination.

The ability to tame high-energy intermediates is important for synthetic chemistry, enabling the construction of complex molecules and propelling advances in the field of synthesis. Along these lines, carbenes and carbenoid intermediates are particularly attractive, but often unknown, high-energy intermediates1,2. Classical methods to access metal carbene intermediates exploit two-electron chemistry to form the carbon-metal bond. However, these methods are usually prohibitive because of reagent safety concerns, limiting their broad implementation in synthesis3-6. Mechanistically, an alternative approach to carbene intermediates that could circumvent these pitfalls would involve two single-electron steps: radical addition to metal to forge the initial carbon-metal bond followed by redox-promoted α-elimination to yield the desired metal carbene intermediate. Here we realize this strategy through a metallaphotoredox platform that exploits iron carbene reactivity using readily available chemical feedstocks as radical sources and α-elimination from six classes of previously underexploited leaving groups. These discoveries permit cyclopropanation and σ-bond insertion into N-H, S-H and P-H bonds from abundant and bench-stable carboxylic acids, amino acids and alcohols, thereby providing a general solution to the challenge of carbene-mediated chemical diversification.

Direct Synthesis of Monofluoromethylthioesters from Acyl Chlorides with Elemental Sulfur and Fluoroiodomethane

AbstractWe report an unprecedented Ni‐catalyzed direct monofluoromethylthiolation of acyl chlorides, in situ generated from carboxylic acids, with elemental sulfur (S8) as the S source and fluoroiodomethane (ICH2F) as the CH2F radical source to produce a series of monofluoromethylthioesters in moderate to good yields. This approach features excellent functional group tolerance and broad substrate scope. Additionally, the late‐stage monofluoromethylthiolation of complex bioactive molecules can also be accomplished using this method.

Carbon-based nanomaterials cause toxicity by oxidative stress to the liver and brain in Sprague–Dawley rats

Carbon-based nanomaterials have important research significance in various disciplines, such as composite materials, nanoelectronic devices, biosensors, biological imaging, and drug delivery. Recently, the human and ecological risks associated with carbon-based nanomaterials have received increasing attention. However, the biological safety of carbon based nanomaterials has not been systematically studied. In this study, we used different types of carbon materials, namely, graphene oxide (GO), single-walled carbon nanotubes (SWCNTs), and multiwalled carbon nanotubes (MWCNTs), as models to observe their distribution and oxidative damage in vivo. The results of Histopathological and ultrastructural examinations indicated that the liver and lungs were the main accumulation targets of these nanomaterials. SR-μ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\upmu$$\\end{document}-XRF analysis revealed that SWCNTs and MWCNTs might be present in the brain. This shows that the three types of carbon-based nanomaterials could cross the gas–blood barrier and eventually reach the liver tissue. In addition, SWCNTs and MWCNTs could cross the blood–brain barrier and accumulate in the cerebral cortex. The increase in ROS and MDA levels and the decrease in GSH, SOD, and CAT levels indicated that the three types of nanomaterials might cause oxidative stress in the liver. This suggests that direct instillation of these carbon-based nanomaterials into rats could induce ROS generation. In addition, iron (Fe) contaminants in these nanomaterials were a definite source of free radicals. However, these nanomaterials did not cause obvious damage to the rat brain tissue. The deposition of selenoprotein in the rat brain was found to be related to oxidative stress and Fe deficiency. This information may support the development of secure and reasonable applications of the studied carbon-based nanomaterials.

Primary Radical Effectiveness: Do the Different Chemical Reactivities of Hydroxyl and Chlorine Radicals Matter for Tropospheric Oxidation?

The atmospheric oxidation of organics occurs primarily via reaction cycles involving gas phase radical species, catalysed by nitric oxide (NO), which result in the production of secondary pollutants such as ozone. For these oxidation cycles to occur, they must be initialized by a primary radical, i.e., a radical formed from non-radical precursors. Once formed, these primary radicals can result in the oxidation of organic compounds to produce peroxy radicals that, providing sufficient NO is present, can re-generate "secondary" radicals which can go on to oxidize further organics. Thus, one primary radical can result in the catalytic oxidation of multiple organics. Although the photolysis of ozone in the presence of water vapor to form two hydroxyl (OH) radicals is accepted as the dominant tropospheric primary radical source, multiple other primary radical sources exist and can dominate in certain environments. The chemical reactivity of different radicals to organic and inorganic compounds can be very different, however, and how these differences in radical chemistry impact atmospheric organic oxidation under different atmospheric conditions has not been previously demonstrated. In this work, we use a series of model simulations to investigate the impact of the chemical reactivity of the primary radical on the effectiveness in initializing organic oxidation and thus the production of the secondary pollutant ozone. We compare the chemistries of the OH and atomic chlorine (Cl) radicals and their effectiveness at initializing organic oxidation under different nitrogen oxide and organic concentrations. The OH radical is the dominant tropospheric radical, with both primary and secondary sources. In contrast, Cl has primary sources that show significant spatial heterogeneity throughout the troposphere but is not typically regenerated in catalytic cycles. Both primary OH and Cl can initiate organic oxidation, but this work shows that the relative effectiveness with which they oxidize organics and produce ozone depends on their balance of propagation vs termination reactions which is in turn determined by the chemical environment in which they are produced. In particular, our work shows that in high NOx radical-limited environments, like those found in many urban areas, Cl will be more efficient at oxidizing organics than OH.

SOURCES OF SUPEROXIDE ANION RADICAL IN SMALL INTESTINE TISSUES IN RATS SUBJECTED TO SURGICAL TRAUMA SIMULATED UNDER EXPERIMENTAL MODEL OF POSTTRAUMATIC STRESS DISORDER

The sources of superoxide anion radical (.О ) in the tissues of the small intestine in rats subjected to surgical trauma simulated under an experimental model of posttraumatic stress disorder (PTSD) were investigated. The study involved 42 white Wistar rats weighing 210-230 g, divided into 6 groups: group 1 comprised intact animals, group 2 included animals with the PTSD induced through single-prolonged stress (SPS), group 3 consisted of rats subjected to a sham surgical operation, group 4 comprised animals undergoing laparotomy, group 5 involved rats undergoing a sham surgical operation following SPS, and group 6 included animals undergoing laparotomy under modeled SPS. The rate of .О generation in the small intestine homogenate was measured spectrophotometrically using the nitroblue tetrazolium test. The .О production by NADPH-dependent (microsomal and NO synthase) electron transport chains (ETC), NADH-dependent (mitochondrial) ETC and leukocyte NADPH oxidase was assessed. The findings obtained have demonstrated that experimental SPS modeling leads to an increase in oxidative stress in the small intestine tissues of rats. This is manifested by an increase in the rate of .О formation with the participation of microsomes, mitochondria and leukocyte NADPH oxidase. On the 7th day after laparotomy under the experimental PTSD model, the .О production in the tissues of the small intestine by different sources (microsomes, mitochondria and leukocyte NADPH oxidase) exceeds their values obtained after a single laparotomy or after performing a sham operation under single long-term stress.

Solvent-free thiol-Ene/-Yne click reactions for the synthesis of alkoxysilyl telechelic poly(propylene oxide)s

Thiol-ene/−yne click reactions can be a versatile toolbox for the design and modification of polymers, enhancing functionality and providing opportunities for the development of innovative materials and applications. Here, we report a simple strategy to synthesize alkoxysilyl telechelic poly(propylene oxide)s (PPO)s: a) through a post-polymerization functionalization via Williamson reactions, commercial PPO is modified at the chain-end secondary alcohols with allyl or propargyl units, achieving >99% conversion; b) subsequent click reactions of (3-mercaptopropyl)trimethoxysilane (MPTMS), triggered by thermal and photochemical radical initiators, result in the incorporation of alkoxysilane groups on the polyether chain. Both thermal and photochemical thiol-ene/−yne click pathways are robust methodologies for preparing alkoxysilyl-modified PPOs in excellent yields (> 99%). Optimal conditions were identified as solvent-free, at 65 °C with 2,2′-azobis(2-methylpropionitrile) (AIBN) as the radical source. Detailed NMR analyses confirm the quantitative transformation of vinyl/propargyl functionalities in the resulting alkoxysilyl telechelic PPOs. Preliminary studies on the stability of alkoxysilyl end-groups are reported using 29Si NMR spectroscopy.

Decatungstate‐Photocatalyzed Diastereoselective Dearomative Hydroalkylation of Indoles

AbstractIn this study, we present an efficient and straightforward dearomative hydroalkylation of indoles. By utilizing alkanes or ethers as alkyl radical sources and employing TBADT as a cost‐effective photocatalyst for direct hydrogen atom transfers (HAT), we achieved successful conversion of these heterocyclic derivatives into 2‐alkylindolines with good to excellent yields and high diastereoselectivity under mild reaction conditions.

Visible Light-Induced Reactions of Diazo Compounds and Their Precursors.

In recent years, visible light-induced reactions of diazo compounds have attracted increasing attention in organic synthesis, leading to improvement of existing reactions, as well as to the discovery of unprecedented transformations. Thus, photochemical or photocatalytic generation of both carbenes and radicals provide milder tools toward these key intermediates for many valuable transformations. However, the vast majority of the transformations represent new reactivity modes of diazo compounds, which are achieved by the photochemical decomposition of diazo compounds and photoredox catalysis. In particular, the use of a redox-active photocatalysts opens the avenue to a plethora of radical reactions. The application of these methods to diazo compounds led to discovery of transformations inaccessible by the classical reactivity associated with carbenes and metal carbenes. In most cases, diazo compounds act as radical sources but can also serve as radical acceptors. Importantly, the described processes operate under mild, practical conditions. This Review describes this subfield of diazo compound chemistry, particularly focusing on recent advancements.

Atmospheric Oxidation Capacity Elevated during 2020 Spring Lockdown in Chengdu, China: Lessons for Future Secondary Pollution Control.

This study presents the measurement of photochemical precursors during the lockdown period from January 23, 2020, to March 14, 2020, in Chengdu in response to the coronavirus (COVID-19) pandemic. To derive the lockdown impact on air quality, the observations are compared to the equivalent periods in the last 2 years. An observation-based model is used to investigate the atmospheric oxidation capacity change during lockdown. OH, HO2, and RO2 concentrations are simulated, which are elevated by 42, 220, and 277%, respectively, during the lockdown period, mainly due to the reduction in nitrogen oxides (NOx). However, the radical turnover rates, i.e., OH oxidation rate L(OH) and local ozone production rate P(O3), which determine the secondary intermediates formation and O3 formation, only increase by 24 and 48%, respectively. Therefore, the oxidation capacity increases slightly during lockdown, which is partly attributed to unchanged alkene concentrations. During the lockdown, alkene ozonolysis seems to be a significant radical primary source due to the elevated O3 concentrations. This unique data set during the lockdown period highlights the importance of controlling alkene emission to mitigate secondary pollution formation in Chengdu and may also be applicable in other regions of China given an expected NOx reduction due to the rapid transformation to electrified fleets in the future.

Initiation and Carbene Induced Radical Chain Reactions in CH2F2 Pyrolysis.

High temperature dissociations of organic molecules typically involve a competition between radical and molecular processes. In this work, we use a modeling, experiment, theory (MET) framework to characterize the high temperature thermal dissociation of CH2F2, a flammable hydrofluorocarbon (HFC) that finds widespread use as a refrigerant. Initiation in CH2F2 proceeds via a molecular elimination channel; CH2F2→CHF+HF. Here we show that the subsequent self-reactions of the singlet carbene, CHF, are fast multichannel processes and a facile source of radicals that initiate rapid chain propagation reactions. These have a marked influence on the decomposition kinetics of CH2F2. The inclusion of these reactions brings the simulations into better agreement with the present and literature experiments. Additionally, flame simulations indicate that inclusion of the CHF+CHF multichannel reaction leads to a noticeable enhancement in predictions of laminar flame speeds, a key parameter that is used to determine the flammability of a refrigerant.

Complexes of Borane and 1,3,5‐Triazinane‐Derived Carbenes

AbstractComplexes of borane with six‐membered N‐heterocyclic carbenes derived from readily accessible 1,3,5‐triazinium salts are described. Similar to the widely used imidazolium‐type borane complex, the obtained complexes behave as agents for the hydrogen atom transfer in the Giese reaction and as sources of the boryl radicals in addition to imines. The amine nitrogen of these complexes does not undergo alkylation, but it can bind with another borane molecule.

Pyrogenic HONO seen from space: insights from global IASI observations

Abstract. Nitrous acid (HONO) is a key atmospheric component, acting as a major source of the hydroxyl radical (OH), the primary oxidant in the Earth's atmosphere. However, understanding its spatial and temporal variability remains a significant challenge. Recent TROPOspheric Monitoring Instrument (TROPOMI)/Sentinel-5 Precursor (S5P) ultraviolet–visible (UV–Vis) measurements of fresh fire plumes shed light on the impact of global pyrogenic HONO emissions. Here, we leverage Infrared Atmospheric Sounding Interferometer (IASI)/MetOp's global infrared satellite measurements, complementing midday TROPOMI observations with morning and evening overpasses, to detect and retrieve pyrogenic HONO in 2007–2023. Employing a sensitive detection method, we identify HONO enhancements within concentrated fire plumes worldwide. Most detections are in the Northern Hemisphere (NH) mid- and high latitudes, where intense wildfires and high injection heights favour HONO detection. IASI's nighttime measurements yield 10-fold more HONO detections than daytime measurements, emphasizing HONO's extended lifetime in the absence of photolysis during the night. The annual detection count increases by at least 3–4 times throughout the IASI time series, mirroring the recent surge in intense wildfires at these latitudes. Additionally, we employ a neural-network-based algorithm for retrieving pyrogenic HONO total columns from IASI and compare them with TROPOMI in the same fire plumes. The results demonstrate TROPOMI's efficacy in capturing HONO enhancements in smaller fire plumes and in proximity to fire sources, while IASI's morning and evening overpasses enable HONO measurements further downwind, highlighting the survival of HONO or its secondary formation along long-range transport in smoke plumes.

Visible‐Light‐Mediated Alkylation of N‐Heteroarenes Using 2‐Mercaptothiazolinium Salts as Alkyl Radical Source

A visible‐light‐mediated radical heteroarylation of 2‑mercaptothiazolinium salts with N‐heteroarenes is reported, furnishing the corresponding functionalized N‐heteroarenes in good to high yields. Various alkyl bromides were converted conveniently into redox‐active thiazolinium salts and subsequently into alkyl radicals by reaction with an excited‐state photocatalyst. This mild protocol permits efficient functionalization of various N‐heteroarenes with a wild range of cyclic and acyclic primary and secondary alkyl groups.

Radical N2-Retention Cyclizations of Aryl Diazoniums: Access to 7/8/9-Membered Heterocycles.

We report herein a modular approach to synthesizing diverse functionalized 7/8/9-membered poly-N-containing heterocycles via oxidative radical N2-retention cyclizations of allylic aryl diazonium salts using CF3SO2Na as a CF3 radical source. A range of trifluoromethylated benzotriazepines, benzotriazocines, and benzotriazonines were obtained in moderate to good yields. This transition-metal-free protocol demonstrates atom economy, safe conditions, broad functional group tolerance, and availability of readily accessible reagents.

Reactive oxygen species and their role in the andrological factor of couple fertility.

Reactive oxygen species play a significant role in male fertility and infertility. They are essential for physiological processes, but when their concentration becomes excessive, they can be a cause of various sperm pathologies. Seminal leukocytes and pathologically abnormal sperm are the primary sources of oxygen radicals in ejaculate. They negatively affect sperm quality, including DNA fragmentation and sperm motility impairment. Addressing increased concentrations of reactive oxygen species involves various appropriate lifestyle modifications and measures, including the use of antioxidants, treatment of urogenital infections, management of varicocele, weight reduction, and others. In many cases, these interventions can lead to adjustments in the condition and improvement in sperm quality. Such improvements can subsequently lead to enhanced outcomes in assisted reproduction or even an increased likelihood of natural conception. In some instances, the need for donor sperm may be eliminated. However, a key factor is adhering to a sufficiently prolonged treatment, which requires patience on the part of both, the physician and the patient.

Immobilized lipase enzyme on green synthesized magnetic nanoparticles using Psidium guava leaves for dye degradation and antimicrobial activities.

Zinc ferrite nanoparticles (ZnF NPs) were synthesized by a green method using Psidium guava Leaves extract and characterized via structural and optical properties. The surface of ZnF NPs was stabilized with citric acid (CA) by a direct addition method to obtain (ZnF-CA NPs), and then lipase (LP) enzyme was immobilized on ZnF-CA NPs to obtain a modified ZnF-CA-LP nanocomposite (NCs). The prepared sample's photocatalytic activity against Methylene blue dye (MB) was determined. The antioxidant activity of ZnF-CA-LP NCs was measured using 1,1-diphenyl-2-picryl hydrazyl (DPPH) as a source of free radicals. In addition, the antibacterial and antibiofilm capabilities of these substances were investigated by testing them against gram-positive Staphylococcus aureus (S. aureus ATCC 25923) and gram-negative Escherichia coli (E. coli ATCC 25922) bacterial strains. The synthesized ZnF NPs were discovered to be situated at the core of the material, as determined by XRD, HRTEM, and SEM investigations, while the CA and lipase enzymes were coated in this core. The ZnF-CA-LP NCs crystallite size was around 35.0nm at the (311) plane. Results obtained suggested that 0.01g of ZnF-CA-LP NCs achieved 96.0% removal of 5.0ppm of MB at pH 9.0. In-vitro zone of inhibition (ZOI) and minimum inhibitory concentration (MIC) results verified that ZnF-CA-LP NCs exhibited its encouraged antimicrobial activity against S. aureus and E. coli (20.0 ± 0.512, and 27.0 ± 0.651mm ZOI, respectively) & (1.25, and 0.625μg/ml MIC, respectively). ZnF-CA-LP NPs showed antibiofilm percentage against S. aureus (88.4%) and E. coli (96.6%). Hence, ZnF-CA-LP NCs are promising for potential applications in environmental and biomedical uses.

Effect of Giving Jamblang (Syzygium cumini) Leaf Extract on Testosterone Serum Level and Concentration of Spermatozoa in Male Rats Intoxicated with Lead Acetate

Lead is a source of free radicals in the environment. Lead accumulation in the blood generates increasing reactive oxygen species (ROS) in the body and various health problems, including male infertility. One effort that can be made to prevent this problem is to use antioxidants from natural sources such as jamblang (Syzygium cumini) leaf extract. This study is experimental with a randomised posttest-only control group design method. The object of this study was 30 white rats (Rattus norvegicus strain Wistar) which were divided into five groups (K-, K+, P1, P2, and P3). Lead acetate was given as much as 40 mg/kgBW in groups K+, P1, P2, P3 orally for 30 days. Jamblang (Syzygium cumini) leaf extract was given 50 mg/kgBW in the P1 group, 150 mg/kgBW in the P2 group, and 300 mg/kgBW in the P3 group orally for 30 days. Testosterone levels were examined using blood serum taken through the retro-orbital vein and examined using the Enzyme-Linked Immunosorbent Assay (ELISA) method. Spermatozoa were taken from the vas deferens and counted using the Neubauer counting chamber. The average level of testosterone serum was at K-2.47 ± 0.59 nmol/ml, K+ 2.23 ± 0.45 nmol/ml, P1 2.35 ± 0.65 nmol/ml, P2 2.56 ± 0 .73 nmol/ml, P3 1.96 ± 0.59 nmol/ml, there was no significant difference statistically (p > 0.05). The average concentration of spermatozoa at K-32.06 ± 2.66 million/ml, K+ 19.45 ± 8.07 million/ml, P1 27.05 ± 1.89 million/ml, P2 28.65 ± 1.10 million/ml, P3 27.11 ± 5.64 million/ml, statistically there was a significant difference (p < 0.05). There was no effect of giving jamblang (Syzygium cumini) leaf extract on testosterone serum levels and there was an effect of giving jamblang (Syzygium cumini) leaf extract on the concentration of spermatozoa of male Rattus norvegicus rats intoxicated with lead acetate. Keywords: lead acetate, jamblang leaf extract, testosterone, spermatozoa

Microcontaminants degradation in tertiary effluent by modified solar photo-Fenton process at neutral pH using organic iron complexes: Influence of the peroxide source and matrix composition

Peroxymonosulfate (HSO5–) and persulfate (S2O82–), both sources of sulfate radicals (SO4*–), were evaluated for the first time in modified solar photo-Fenton using Fe-chelating agents (nitriloacetic acid (NTA), ethylene diaminetetraacetic acid (EDTA), ethylenediamine-N,N′-disuccinic acid (EDDS) and citrate (Cit)) in comparison with hydrogen peroxide (H2O2) to degrade benzophenone-3 (BP-3), fipronil (FIP) and propylparaben (PPB) (100 µg L–1 each) in municipal tertiary effluent. Increasing HSO5– concentrations from 1.5 to 5.9 mmol L–1 reached ≥ 96 % removal for all iron complexes, while treatment efficiencies for all tested S2O82– concentrations (1.5–5.9 mmol L–1) were limited to 20 % to 55 %. This difference can be attributed to a pH decrease in the HSO5– system. The influence of pH and matrix composition upon treatment performance were also assessed in the FeNTA/S2O82– system, which was more efficient at pH < 7.0 due to higher availability of soluble iron, and partial removal of bicarbonate and humic acids caused by acidification. Matrix composition significantly influenced the process as higher degradation rates were achieved after isolated or combined removals of chloride, bicarbonate and sulfate. The comparison between naproxen (a high electron density compound) degradation and that of BP-3, FIP, and PPB by SO4*– - based advanced oxidation processes (SR-AOPs) was used to evaluate the influence of target compound structures upon treatment performance. S2O82− and HSO5– were ineffective for treatment at pH 7.0. Thus, H2O2 was the best peroxide source for target compounds degradation at neutral pH as this is the natural pH of municipal tertiary effluent and results indicated that the assessment and choice for SR-AOPs should consider the chemical structure of target compounds.

The white rot basidiomycete Gelatoporia subvermispora produces fatty aldehydes that enable fungal manganese peroxidases to degrade recalcitrant lignin structures.

The ability of some white rot basidiomycetes to remove lignin selectively from wood indicates that low molecular weight oxidants have a role in ligninolysis. These oxidants are likely free radicals generated by fungal peroxidases from compounds in the biodegrading wood. Past work supports a role for manganese peroxidases (MnPs) in the production of ligninolytic oxidants from fungal membrane lipids. However, the fatty acid alkylperoxyl radicals initially formed during this process are not reactive enough to attack the major structures in lignin. Here, we evaluate the hypothesis that the peroxidation of fatty aldehydes might provide a source of more reactive acylperoxyl radicals. We found that Gelatoporia subvermispora produced trans-2-nonenal, trans-2-octenal, and n-hexanal (a likely metabolite of trans-2,4-decadienal) during the incipient decay of aspen wood. Fungal fatty aldehydes supported the in vitro oxidation by MnPs of a nonphenolic lignin model dimer, and also of the monomeric model veratryl alcohol. Experiments with the latter compound showed that the reactions were partially inhibited by oxalate, the chelator that white rot fungi employ to detach Mn3+ from the MnP active site, but nevertheless proceeded at its physiological concentration of 1 mM. The addition of catalase was inhibitory, which suggests that the standard MnP catalytic cycle is involved in the oxidation of aldehydes. MnP oxidized trans-2-nonenal quantitatively to trans-2-nonenoic acid with the consumption of one O2 equivalent. The data suggest that when Mn3+ remains associated with MnP, it can oxidize aldehydes to their acyl radicals, and the latter subsequently add O2 to become ligninolytic acylperoxyl radicals.IMPORTANCEThe biodegradation of lignin by white rot fungi is essential for the natural recycling of plant biomass and has useful applications in lignocellulose bioprocessing. Although fungal peroxidases have a key role in ligninolysis, past work indicates that biodegradation is initiated by smaller, as yet unidentified oxidants that can infiltrate the substrate. Here, we present evidence that the peroxidase-catalyzed oxidation of naturally occurring fungal aldehydes may provide a source of ligninolytic free radical oxidants.

Simplifying Nitration Chemistry with Bench-stable Organic Nitrating Reagents.

Nitro compounds play a crucial role in academia and industries, serving as building blocks for the synthesis of drugs, agrochemicals, and materials. Nitration, a fundamental process in organic synthesis, has undergone significant evolution since the 19th century. While electrophilic nitration dominates historically, recent decades have seen a focus on new reagents and their reactivity modes for achieving mild and robust synthesis of nitro compounds. Our group has a longstanding interest in developing cost-effective, readily available, recyclable nitrating reagents derived from organic scaffolds. These reagents serve as a controllable source of nitryl radical and nitronium ion species, enabling mild and practical nitration of hydrocarbons with exceptional functional group tolerance. This account details the development of nitrating reagents and their diverse applications in catalytic nitration across various classes of organic molecules.