Reactions Of Organic Compounds Research Articles

What are the DNA lesions underlying formaldehyde toxicity?

Formaldehyde is a highly reactive organic compound. Humans can be exposed to exogenous sources of formaldehyde, but formaldehyde is also produced endogenously as a byproduct of cellular metabolism. Because formaldehyde can react with DNA, it is considered a major endogenous source of DNA damage. However, the nature of the lesions underlying formaldehyde toxicity in cells remains vastly unknown. Here, we review the current knowledge of the different types of nucleic acid lesions that are induced by formaldehyde and describe the repair pathways known to counteract formaldehyde toxicity. Taking this knowledge together, we discuss and speculate on the predominant lesions generated by formaldehyde, which underly its natural toxicity.

Association between ethylene oxide exposure and sex steroid hormone levels in male adults in the United States

Sex steroid hormones play important roles in maintaining our health systems, including reproductive function and developmental health. Ethylene oxide (EtO) is a reactive organic compound that is widely used in the gas sterilization of materials such as foods, spices, and medical devices. Previous studies have suggested that EtO exposure is associated with carcinogenic risk, neurotoxicity, and reproductive toxicity. However, no studies focusing on the relationship between EtO exposure and changes in sex steroid hormone levels have been performed in human. The present study investigated the association between blood EtO levels and serum sex steroid hormone levels in 1,635 adult men from the NHANES 2013-2016. Multivariate linear regression analyses, a positive correlation between blood EtO and total testosterone levels, and the testosterone to estradiol ratio. Moderate EtO exposure was associated with a decrease in estradiol levels, but no relationship was found at the highest exposure range. No significant associations were observed between EtO exposure and free testosterone, bioavailable testosterone, or sex hormone-binding globulin levels. These findings suggest EtO exposure could impact human sex steroid hormone production, although analysis in females and further verification through prospective studies should be performed.

Positive association of ethylene oxide levels with young stroke: a population-based study.

Ethylene oxide (EtO), a highly reactive organic compound with extensive industrial applications, poses significant health risks. The association between EtO exposure and stroke was not well established. This study examined the association between EtO exposure and stroke among US adults using data from the 2013-2018 National Health and Nutrition Examination Survey (NHANES). We used appropriately weighted multifactorial logistic regression models to analyze the data and validated the findings with smoothed curve fitting. Stratified analysis and interaction assessments were performed to evaluate the robustness of the findings. The study included 5,071 participants, balanced between men and women, with a stroke prevalence of 4.1%. Higher EtO levels were associated with rising rates of stroke (OR = 1.23, 95% CI: 1.06-1.42). Individuals in the top 25% group displayed a stroke prevalence 1.6 times higher than those in the bottom 25% group (OR = 1.60, 95%CI: 1.03-2.48). Stratified analysis demonstrated a significant positive association between EtO and stroke in individuals under 50 years (OR = 1.94, 95%CI: 1.38-2.72), while no significant association was found in those aged 50 and above (OR = 0.97, 95%CI: 0.83-1.14). This study identified a significant association between EtO exposure and stroke occurrence in young adults in the United States.

Innovative Solutions for Food Analysis: Microextraction Techniques in Lipid Peroxidation Product Detection

Lipid peroxidation, the most aggressive reaction in food, results in the formation of reactive organic compounds that detrimentally impact food sensory qualities and consumers’ health. While controlled lipid peroxidation can enhance flavors and appearance in certain foods, secondary peroxidation products lead to sensory deterioration in a variety of products, such as oils, alcoholic beverages, and meat. This publication reviews the use of modern analytical techniques for detecting and quantifying carbonyl compounds, i.e., secondary lipid peroxidation products. The paper focuses specifically on microextraction-based methods: dispersive liquid-liquid microextraction (DLLME), solid-phase microextraction (SPME), and gas-diffusion microextraction (GDME). These techniques offer efficient and sensitive approaches to extracting and quantifying lipid oxidation products and contribute to the understanding of oxidative deterioration in various food products. The review outlines recent advancements, challenges, and limitations in these microextraction techniques, as well as emphasizes the potential for further innovation and improvement in the field of food analysis.

Tetrafluorenofulvalene as a sterically frustrated open-shell alkene

Electronic and steric effects are known to greatly influence the structure, characteristics and reactivity of organic compounds. A typical π bond is weakened by oxidation (corresponding to the removal of electrons from bonding orbitals), by reduction (through addition of electrons to antibonding orbitals) and by unpairing of the bonding electrons, such as in the triplet state. Here we describe tetrafluorenofulvalene (TFF), a twisted, open-shell alkene for which these general rules do not hold. Through the synthesis, experimental characterization and computational analysis of its charged species spanning seven redox states, the central alkene bond in TFF is shown to become substantially stronger in the tri- and tetraanion, generated by chemical reduction. Furthermore, although its triplet state contains a weaker alkene bond than the singlet, in the quintet state its bond order increases substantially, yielding a flatter structure. This behaviour originates from the doubly bifurcated topology of the underlying spin system and can be rationalized by the balancing effects of benzenoid aromaticity and spin pairing.

Kinetics of hypochlorous acid reactions with organic and chloride-containing tropospheric aerosol.

Chlorine plays an important role in tropospheric oxidation processes, in both marine and continental environments. Although modeling studies have explored the importance of halogen chemistry, uncertainty remains in associated chemical mechanisms and fundamental kinetics parameters. Prior kinetics measurements of multiphase halogen recycling reactions have been largely performed with dilute, bulk solutions, leaving unexplored more realistic chemical systems which have high solute concentrations and are internally mixed with both halide and organic components. Here, we address the multiphase kinetics of gaseous HOCl using an aerosol flow tube and aerosol mass spectrometer to study its reactions with particulate chloride, using atmospherically relevant particle acidity, solute concentrations, and ionic strength. We also investigate the chemistry that results when biomass burning (BB) aerosol components and chloride are internally mixed. Using pH-buffered deliquesced particles, we show that the rate constant for reaction of dissolved HOCl with H+ and Cl- at high relative humidity (RH) (80-85%) is within a factor of two of the literature value for bulk phase conditions. However, at lower RH values (60-70%) where the particles are considerably more concentrated, the rate constant for chloride loss from the particles is an order of magnitude higher. For pure organic compounds commonly found in biomass burning (BB) aerosol, such as coniferaldehyde, salicylic acid and furfural, an increase in the aerosol chlorine content occurs with HOCl exposure, indicating the formation of organochlorine species. Together, these independent findings explain results for internally mixed aerosol particles with both chloride and BB components present where we observed behavior consistent with both chloride loss and organochlorine formation occurring simultaneously upon HOCl exposure. Our results indicate that chlorine recycling via HOCl uptake by chloride-containing particles will occur in the atmosphere efficiently over a wide range of RH conditions, even when reactive organic compounds are present in the same particles as chloride. Simultaneously, formation of organochlorine compounds, which are commonly toxic, is likely occurring when reactive organic components are present.

Anthropogenic secondary organic aerosol and ozone production from asphalt-related emissions

Asphalt paving contributes to nationwide reactive organic compound emissions and these emissions can enhance local, predominantly urban, fine particulate matter concentrations.

Low NOX and high organic compound emissions from oilfield pumpjack engines

We measured a comprehensive suite of pollutants emitted from 58 natural gas-fueled pumpjack engines in Utah’s Uinta Basin. Air–fuel equivalence ratio (the ratio of air taken in by the engine to the amount of air needed for combustion of the fuel) was a strong predictor of emissions. Higher air–fuel equivalence ratios led to lower oxides of nitrogen (NOX) emissions and higher emissions of organic compounds. For engines with air–fuel equivalence ratios greater than 3 (34% of 58 total engines tested), a median of 57% of the fuel gas passed through the engine uncombusted, and exhaust gas contained a median of only 3 ppm NOX. Lower air–fuel equivalence ratios were associated with less fuel slip, higher NOX, and the formation of more reactive organic compounds, including alkenes and carbonyls. Average NOX emissions measured in this study were only 9% of average emissions from natural gas-fueled pumpjack engines in a regulatory oil and gas emissions inventory. In contrast, volatile organic compound emissions in the study were 15 times higher than in the inventory. We hypothesize that these discrepancies are due to changes in emissions as engines operate at lower loads and as they age in field conditions. In addition to improving emissions inventories and the effectiveness of related regulatory efforts, this work will improve the ability of photochemical models to simulate the atmospheric impacts of oil and gas development.

Bio-grafted silica to make an asphalt road a sink for reactive environmental pollutants

Asphalt-surfaced areas such as roads have been reported as major non-combustion sources of reactive organic compounds in urban areas. Emission of latter compounds from asphalt is exacerbated due to exposure to sunlight and high temperature, contributing to negative human and environmental health outcomes. Furthermore, loss of asphalt components over time is linked to bitumen's aging that reduces service life of roads. Here, we introduce a designed bio-grafted-silica nano-filler derived from wood pellet as a sink for latter volatile compounds in an asphalt mixture. Molecular modeling calculations showed the remarkable adsorptive activity of the bio-grafted silica for trapping select asphalt volatiles, especially for the sulfur-containing aromatics and the oxygen-containing aromatics. Laboratory experiment revealed that the bitumen modified with bio-grafted silica exhibited up to 23% lower signs of aging. Thermogravimetric analysis proved that the modified bitumen exhibited a 16% reduction in mass loss compared to neat bitumen. Dynamic vapor sorption analysis also showed bio-grafted silica adsorbed higher amounts of a candidate volatile than pristine silica. The study outcomes highlights the advantages of a bio-derived modifier in asphalt to address concerns associated with the loss of hazardous compounds.

Перспективи використання місцевих сировинних ресурсів у виробництві поліпшувачів ґрунту

Goal. To analyze the qualitative characteristics of local raw materials of different origins and assess the prospects of its rational use as a source of organic matter for the production of various types of improvers and secondary raw materials in Ukraine for the production of various types of soil improvers, Methods. Laboratory — for the study of agrochemical properties of the main types of local raw materials, conducted according to certified methods, followed by statistical data processing. Results. The agrochemical characteristics are given of fertilizing and reclamation materials of organic and mineral origin, which are considered as a source of nutrients and organic compounds, and can be used for the manufacture of soil improvers after the relevant technological solutions. Most of the analyzed materials are characterized by the significant potential for humus formation in soils. Conclusions. The solution of the ecological resource situation in Ukraine largely depends on the treatment of local raw materials, because it is the main factor in environmental pollution, it “frozen” a certain part of the resource and energy potential. This affects the balance of economic development of Ukraine in both environmental and resource terms. It is proved that with organic local raw materials the soil receives a complex of different chemical compositions, degree of stability, and reactivity of organic compounds, which cause significant reclamation potential of soil improvers. Involvement of local raw materials of different genesis in the production of soil improvers, the introduction of processing technologies to improve their reclamation properties, will allow obtaining a quality product balanced in terms of humus and nutrients.

Insight into structure-property relationship of organometallic terpyridine wires: Combined theoretical and experimental study

Recent development in combined theoretical and experimental analysis methods offer an attractive opportunity to investigate organometallic materials. The selection of optimally combined characterization techniques allows for an effective description and even prediction of structure-property relationship occurring in terpyridine (TPY) molecules. In this work, secondary ion mass spectrometry (SIMS), quantitative and qualitative characterization, hand-in-hand, with density functional theory (DFT) calculations, can aid analysis of the chemical stability and reactivity of organic compounds. A case study was based on the characterization of [M-(TPY)2]2+ complexes (M: Co/Fe) with specific organic and organometallic architectures. The SIMS mass spectra showed the step-by-step molecules fragmentation and the quantitative SIMS analysis allowed to predict its direction. Analysis of electron density, electrostatic potential visualization, and calculated bonds length and HOMO-LUMO energetic gap were employed to confirm the differences between the bond-breaking mechanism depending on the metal atom bound to the terpyridine. The combined DFT/SIMS approach was successfully used to assess the chemical stability of various isomers of the TPY compounds, and to determine the possible fragmentation pathways depending largely on the metal centre present within the TPY structure.

Evolution of Atmospheric Total Organic Carbon from Petrochemical Mixtures.

Reactive organic compounds play a central role in the formation of ozone and secondary organic aerosols. The ability to accurately predict their fate, in part, relies upon quantitative knowledge of the chemical and physical parameters associated with the total organic carbon (TOC), which includes both precursors and oxidation products that evolve in the atmosphere over short to long time scales. However, such knowledge, obtained via limited carbon closure experiments, has not been attained for complex anthropogenic emissions. Here we present the first comprehensive characterization of TOC in the atmospheric oxidation of organic vapors from light and heavy oil mixtures associated with oil sand operations. Despite the complexity of the investigated oil mixtures, we are able to achieve carbon closure (83-116%) within the uncertainties (±20%), with the degree of the closure being dependent upon the vapor composition and NOx levels. In contrast to biogenic precursors (e.g., α-pinene), the photochemical time scale required for a largely complete oxidation and evolution of chemical parameters is very long for the petrochemical vapors (i.e., ∼7-10 days vs ∼1 day), likely due to the lower initial precursor reactivity. This suggests that petrochemical emissions and their impacts are likely to extend further spatially than biogenic emissions, and retain more of their complex composition and reactivity for many days. The results of this work provide key parameters to regional models for further improving the representation of the chemical evolution of petrochemical emissions.

Acyl(imidoyl)ketenes: Reactive Bidentate Oxa/Aza-Dienes for Organic Synthesis

Polyfunctional building blocks are essential for the implementation of diversity-oriented synthetic strategies, highly demanded in small molecule libraries’ design for modern drug discovery. Acyl(imidoyl)ketenes are highly reactive organic compounds, bearing both oxa- and aza-diene moieties, conjugated symmetrically to the ketene fragment, enabling synthesis of various skeletally diverse heterocycles on their basis. The highlights of reactions utilizing acyl(imidoyl)ketenes are high yields, short reaction time (about several minutes), high selectivity, atom economy, and simple purification procedures, which benefits the drug discovery. The present review focuses on the approaches to thermal generation of acyl(imidoyl)ketenes, patterns of their immediate transformations via intra- and intermolecular reactions, including the reactions of cyclodimerization, in which either symmetric or dissymmetric heterocycles can be formed. Recent advances in investigations on mechanisms, identifications of intermediates, and chemo- and regioselectivity of reactions with participation of acyl(imidoyl)ketenes are also covered.

Schiff Bases: Interesting Scaffolds with Promising Antitumoral Properties

Schiff bases, named after Hugo Schiff, are highly reactive organic compounds broadly used as pigments and dyes, catalysts, intermediates in organic synthesis, and polymer stabilizers. Lots of Schiff bases are described in the literature for various biological activities, including antimalarial, antibacterial, antifungal, anti-inflammatory, and antiviral. Schiff bases are also known for their ability to form complexes with several metals. Very often, complexes of Schiff bases with metals and Schiff bases alone have demonstrated interesting antitumor activity. Given the innumerable vastness of data regarding antitumor activity of all these compounds, we focused our attention on mono- and bis-Schiff bases alone as antitumor agents. We will highlight the most significant examples of compounds belonging to this class reported in the literature.

Emission drivers and variability of ambient isoprene, formaldehyde and acetaldehyde in north-west India during monsoon season

Isoprene, formaldehyde and acetaldehyde are important reactive organic compounds which strongly impact atmospheric oxidation processes and formation of tropospheric ozone. Monsoon meteorology and the topography of Himalayan foothills cause surface emissions to get rapidly transported both horizontally and vertically, thereby influencing atmospheric processes in distant regions. Further in monsoon, Indo-Gangetic Plain is a major rice growing region of the world and daytime hourly ozone can frequently exceed phytotoxic dose of 40 ppb O3. However, the sources and ambient variability of these compounds which are potent ozone precursors are unknown. Here, we investigate the sources and photochemical processes driving their emission/formation during monsoon season from a sub-urban site at the foothills of the Himalayas. The measurements were performed in July, August and September using a high sensitivity mass spectrometer. Average ambient mixing ratios (±1σ variability) of isoprene, formaldehyde, acetaldehyde, and the sum of methyl vinyl ketone and methacrolein (MVK+MACR), were 1.4 ± 0.3 ppb, 5.7 ± 0.9 ppb, 4.5 ± 2.0 ppb, 0.75 ± 0.3 ppb, respectively, and much higher than summertime values in May. For isoprene these values were comparable to mixing ratios observed over tropical forests. Surprisingly, despite occurrence of anthropogenic emissions, biogenic emissions were found to be the major source of isoprene with peak daytime isoprene driven by temperature (r ≥ 0.8) and solar radiation. Photo-oxidation of precursor hydrocarbons were the main sources of acetaldehyde, formaldehyde and MVK+MACR. Ambient mixing ratios of all the compounds correlated poorly with acetonitrile (r ≤ 0.2), a chemical tracer for biomass burning suggesting negligible influence of biomass burning during monsoon season. Our results suggest that during monsoon season when radiation and rain are no longer limiting factors and convective activity causes surface emissions to be transported to upper atmosphere, biogenic emissions can significantly impact the remote upper atmosphere, climate and ozone affecting rice yields.

One‐Electron Reduction of Redox‐Active Esters to Generate Carbon‐Centered Radicals

The one‐electron reduction (OER) can profoundly affect the structure and reactivity of organic compounds. OER induced radical decarboxylative functionalizations of redox‐active esters have gained wide concerns in this century. In this review, we present recent advances using redox‐active esters as carbon‐centered radical precursors to form carbon–carbon and carbon–heteroatom bonds.

Organic Fanatic: A Quiz-Based Mobile Application Game to Support Learning the Structure and Reactivity of Organic Compounds

Organic Fanatic is a free-of-charge quiz-based mobile application game that encourages students to test their abilities and enhance their learning of organic structure and reactivity through a fun,...

Inorganic halide perovskite materials and solar cells

Organic-inorganic perovskite solar cells (PSCs) have achieved an inspiring third-party-certificated power conversion efficiency (PCE) of 25.2%, which is comparable with commercialized silicon (Si) and copper indium gallium selenium solar cells. However, their notorious instability, including their deterioration at elevated temperature, is still a serious issue in commercial applications. This thermal instability can be ascribed to the high volatility and reactivity of organic compounds. As a result, solar cells based on inorganic perovskite materials have drawn tremendous attention, owing to their excellent stability against thermal stress. In the last few years, PSCs based on inorganic perovskite materials have seen an astonishing development. In particular, CsPbI3 and CsPbI2Br PSCs demonstrated outstanding PCEs, exceeding 18% and 16%, respectively. In this review, we systematically discuss the properties of inorganic perovskite materials and the device configuration of inorganic PSCs as well as review the progress in PCE and stability. Encouragingly, all-inorganic PSCs, in which all functional layers are inorganic, provide a feasible approach to overcome the thermal instability issue of traditional organic-inorganic PSCs, leading to new perspectives toward commercial production of PSCs.

Photochemical aging of atmospherically reactive organic compounds involving brown carbon at the air–aqueous interface

Abstract. Water-soluble brown carbon in the aqueous core of aerosol may play a role in the photochemical aging of organic film on the aerosol surface. To better understand the reactivity and photochemical aging processes of organic coating on the aqueous aerosol surface, we have simulated the photosensitized reaction of organic films made of several long-chain fatty acids in a Langmuir trough in the presence or absence of irradiation. Several chemicals (imidazole-2-carboxaldehyde and humic acid), PM2.5 samples collected from the field, and secondary organic aerosol samples generated from a simulation chamber were used as photosensitizers to be involved in the photochemistry of the organic films. Stearic acid, elaidic acid, oleic acid, and two different phospholipids with the same carbon chain length and different degrees of saturation, i.e. 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and 1,2-dioleoylsn-glycero-3-phosphocholine (DOPC), were chosen as the common organic film-forming species in this analysis. The double bond (trans and cis) in unsaturated organic compounds has an effect on the surface area of the organic monolayer. The oleic acid (OA) monolayer possessing a cis double bond in an alkyl chain is more expanded than elaidic acid (EA) monolayers on artificial seawater that contain a photosensitizer. Monitoring the change in the relative area of DOPC monolayers has shown that DOPC does not react with photosensitizers under dark conditions. Instead, the photochemical reaction initiated by the excited photosensitizer and molecular oxygen can generate new unsaturated products in the DOPC monolayers, accompanied by an increase in the molecular area. The DSPC monolayers did not yield any photochemical oxidized products under the same conditions. The spectra measured with polarization modulation-infrared reflection–absorption spectroscopy (PM-IRRAS) were also consistent with the results of a surface pressure–area isotherm. Here, a reaction mechanism explaining these observations is presented and discussed. The results of PM2.5 and SOA samples will contribute to our understanding of the processing of organic aerosol aging that alters the aerosol composition.

Effects of inorganic salts on the heterogeneous OH oxidation of organic compounds: insights from methylglutaric acid–ammonium sulfate

Abstract. Atmospheric particles, consisting of inorganic salts, organic compounds and a varying amount of water, can continuously undergo heterogeneous oxidation initiated by gas-phase oxidants at the particle surface, changing the composition and properties of particles over time. To date, most studies focus on the chemical evolution of pure organic particles upon oxidation. To gain more fundamental insights into the effects of inorganic salts on the heterogeneous kinetics and chemistry of organic compounds, we investigate the heterogeneous OH oxidation of 3-methylglutaric acid (3-MGA) particles and particles containing both 3-MGA and ammonium sulfate (AS) in an organic-to-inorganic mass ratio of 2 in an aerosol flow tube reactor at a high relative humidity of 85.0 %. The molecular information of the particles before and after OH oxidation is obtained using the direct analysis in real time (DART), a soft atmospheric pressure ionization source coupled to a high-resolution mass spectrometer. Optical microscopy measurements reveal that 3-MGA–AS particles are in a single liquid phase prior to oxidation at high relative humidity. Particle mass spectra show that C6 hydroxyl and C6 ketone functionalization products are the major products formed upon OH oxidation in the absence and presence of AS, suggesting that the dissolved salt does not significantly affect reaction pathways. The dominance of C6 hydroxyl products over C6 ketone products could be explained by the intermolecular hydrogen abstraction by tertiary alkoxy radicals formed at the methyl-substituted tertiary carbon site. On the other hand, kinetic measurements show that the effective OH uptake coefficient, γeff, for 3-MGA–AS particles (0.99±0.05) is smaller than that for 3-MGA particles (2.41±0.13) by about a factor of ∼2.4. A smaller reactivity observed in 3-MGA–AS particles might be attributed to a higher surface concentration of water molecules and the presence of ammonium and sulfate ions, which are chemically inert to OH radicals, at the particle surface. This could lower the collision probability between the 3-MGA and OH radicals, resulting in a smaller overall reaction rate. Our results suggest that inorganic salts likely alter the overall heterogeneous reactivity of organic compounds with gas-phase OH radicals rather than reaction mechanisms in well-mixed aqueous organic–inorganic droplets at a high humidity, i.e., 85 % relative humidity (RH). It also acknowledges that the effects of inorganic salts on the heterogeneous reactivity could vary greatly, depending on the particle composition and environmental conditions (e.g., RH and temperature). For instance, at lower relative humidities, aqueous 3-MGA–AS droplets likely become more concentrated and more viscous before efflorescence, possibly giving rise to diffusion limitation during oxidation under relatively dry or cold conditions. Further studies on the effects of inorganic salts on the diffusivity of the species under different relative humidities within the organic–inorganic particles are also desirable to better understand the role of inorganic salts in the heterogeneous reactivity of organic compounds.