Modular metal-free catalytic radical annulation of cyclic diaryliodoniums to access π-extended arenes

2021 ◽  
Author(s):  
Daqian Zhu ◽  
Hui Peng ◽  
Yameng Sun ◽  
Zhouming Wu ◽  
Yun Wang ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Free Radical ◽  
Transition Metal ◽  
Ethyl Acetate ◽  
Aromatic Hydrocarbons ◽  
Environmentally Friendly ◽  
Metal Free ◽  
Polycyclic Aromatic

Tert-butylamine-catalyzed free radical annulations with cyclic diaryliodoniums occur in environmentally friendly ethyl acetate and do not require transition metal, providing diversified polycyclic aromatic hydrocarbons by modulating substituents.

scholarly journals A topological model for predicting adsorption energies of polycyclic aromatic hydrocarbons on late-transition metal surfaces

2019 ◽  
Vol 4 (2) ◽  
pp. 410-417
Author(s):  
Zhao-Bin Ding ◽  
Matteo Tommasini ◽  
Matteo Maestri
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Transition Metal ◽  
Aromatic Hydrocarbons ◽  
Topological Model ◽  
Late Transition Metal ◽  
Formation Enthalpies ◽  
Transition Metal Surfaces ◽  
Polycyclic Aromatic ◽  
Adsorption Energies ◽  
Late Transition

A topological model for the adsorption of PAHs is derived based on an analogy with the formation enthalpies of metal complexes.

An environmentally friendly method for the determination of polycyclic aromatic hydrocarbons in different soil typologies

2019 ◽  
Vol 16 (7) ◽  
pp. 517
Author(s):  
Flavia De Nicola ◽  
Estefanía Concha-Graña ◽  
Enrica Picariello ◽  
Valeria Memoli ◽  
Giulia Maisto ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Human Health ◽  
Aromatic Hydrocarbons ◽  
Analytical Method ◽  
Solid Phase ◽  
Environmentally Friendly ◽  
Limit Of Quantification ◽  
Industrial Soil ◽  
Relative Standard ◽  
Polycyclic Aromatic

Environmental contextPolycyclic aromatic hydrocarbons (PAHs) are widespread organic pollutants that tend to accumulate in soil. We developed an environmentally friendly analytical method for PAHs to evaluate human health risks associated with their presence in soils. The method is feasible for the analysis of soils with widely varying PAH contamination levels, and is well suited to environmental monitoring studies of relevance to human health. AbstractA microwave-assisted extraction, with a dispersive solid-phase purification step followed by programmed temperature vaporisation–gas chromatography–tandem mass spectrometry, is proposed as an environmentally friendly, simple and cheap analytical method for polycyclic aromatic hydrocarbons (PAHs) in soil. Different extraction and clean-up operating variables were tested to achieve satisfactory analytical performances: trueness from 92 to 114%, limit of quantification (LOQ) from 0.4 to 2µgkg−1 for most PAHs and intermediate precision, calculated as relative standard deviation (RSD), below 10%. The method was validated using both Certified Reference Material and real soil samples collected at sites subjected to different human activities. PAH contents ranged from 0.11 (in holm oak forest soil) to 1mgkg−1 d.w. (in an industrial soil) according to the anthropic gradient. The soil PAH contents measured were used to estimate the risk to human health, which suggested the exposure to the PAHs in soil as a potential risk for human health, especially at the industrial site. The feasibility of the method for soils with different PAH contamination degrees makes it relevant in monitoring programs.

scholarly journals Polycyclic aromatic azomethine ylides: a unique entry to extended polycyclic heteroaromatics

2015 ◽  
Vol 6 (1) ◽  
pp. 436-441 ◽  
Author(s):  
Reinhard Berger ◽  
Manfred Wagner ◽  
Xinliang Feng ◽  
Klaus Müllen
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Azomethine Ylides ◽  
Metal Free ◽  
Polycyclic Aromatic

Based on polycyclic aromatic azomethine ylides, a metal-free “cycloaddition-planarization-sequence” is proposed, providing a unique entry to nitrogen-containing polycyclic aromatic hydrocarbons.

Photoirradiation of representative polycyclic aromatic hydrocarbons and twelve isomeric methylbenz[a]anthracene with UVA light: formation of lipid peroxidation

2006 ◽  
Vol 22 (4) ◽  
pp. 147-156 ◽  
Author(s):  
Qingsu Xia ◽  
Ming W Chou ◽  
Jun J Yin ◽  
Paul C Howard ◽  
Hongtao Yu ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Free Radical ◽  
Methyl Linoleate ◽  
Aromatic Hydrocarbons ◽  
Lipid Peroxide ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Uva Light ◽  
Polycyclic Aromatic

Polycyclic aromatic hydrocarbons (PAHs) are widespread genotoxic environmental pollutants, which require metabolic activation in order to exert biological activities, including mutagenicity and carcinogenicity. Photoactivation is another activation pathway that can lead to PAH genotoxicity. In this paper, we demonstrate that photoirradiation of a series of representative PAHs, with and without bearing a methyl substituent, with UVA light in the presence of methyl linoleate resulted in the formation of methyl linoleate hydroperoxides (a lipid peroxide). The lipid peroxide formation was inhibited by dithiothreitol (DTT) (free radical scavenger), NaN3 (singlet oxygen and free radical scavenger), and superoxide dismutase (SOD) (superoxide scavenger), but was enhanced by the presence of deuterium oxide (D2O) (extends singlet oxygen lifetime). These results suggest that photoirradiation of PAHs by UVA light generates reactive oxygen species (ROS), which induce lipid peroxidation.

Determination of Polycyclic Aromatic Hydrocarbons (PAHs) in Seafood Using Gas Chromatography-Mass Spectrometry: Collaborative Study

2015 ◽  
Vol 98 (2) ◽  
pp. 477-505 ◽  
Author(s):  
Katerina Mastovska ◽  
Wendy R Sorenson ◽  
Jana Hajslova ◽  
J Betzand ◽  
J Binkley ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Sample Preparation ◽  
Ethyl Acetate ◽  
Aromatic Hydrocarbons ◽  
Preparation Method ◽  
Collaborative Study ◽  
Gas Chromatography Mass Spectrometry ◽  
Sample Preparation Method ◽  
Expert Review ◽  
Polycyclic Aromatic

Abstract A collaborative study was conducted to determine selected polycyclic aromatic hydrocarbons (PAHs) and their relevant alkyl homologs in seafood matrixes using a fast sample preparation method followed by analysis with GC/MS. The sample preparation method involves addition of 13C-PAH surrogate mixture to homogenized samples and extraction by shaking with a water–ethyl acetate mixture. After phase separation induced by addition of anhydrous magnesium sulfate–sodium chloride (2 + 1, w/w) and centrifugation, an aliquot of the ethyl acetate layer is evaporated, reconstituted in hexane, and cleaned up using silica gel SPE. The analytes are eluted with hexane–dichloromethane (3 + 1, v/v), the clean extract is carefully evaporated, reconstituted in isooctane, and analyzed by GC/MS. To allow for the use of various GC/MS instruments, GC columns, silica SPE cartridges, and evaporation techniques and equipment, performance-based criteria were developed and implemented in the qualification phase of the collaborative study. These criteria helped laboratories optimize their GC/MS, SPE cleanup, and evaporation conditions; check and eliminate potential PAH contamination in their reagent blanks; and become familiar with the method procedure. Ten laboratories from five countries qualified and completed the collaborative study, which was conducted on three seafood matrixes (mussel, oyster, and shrimp) fortified with 19 selected PAH analytes at five different levels of benzo[a]pyrene (BaP) ranging from 2 to 50 μg/kg. Each matrix had a varying mixture of three different BaP levels. The other studied PAHs were at varying levels from 2 to 250 μg/kg to mimic typical PAH patterns. The fortified analytes in three matrixes were analyzed as blind duplicates at each level of BaP and corresponding other PAH levels. In addition, a blank with no added PAHs for each matrix was analyzed singly. Eight to 10 valid results were obtained for the majority of determinations. Mean recoveries of all tested analytes at the five different concentration levels were all in the range of 70–120%: 83.8–115% in shrimp, 77.3–107% in mussel, and 71.6–94.6% in oyster, except for a slightly lower mean recovery of 68.6% for benzo[ a ]anthracene fortified at 25 μg/kg in oyster (RSDr: 5.84%, RSDR: 21.1%) and lower mean recoveries for anthracene (Ant) and BaP in oyster at all three fortification levels (50.3–56.5% and 48.2–49.7%, respectively). The lower mean recoveries of Ant and BaP were linked to degradation of these analytes in oyster samples stored at –20°C, which also resulted in lower reproducibility (RSDR values in the range of 44.5–64.7% for Ant and 40.6–43.5% for BaP). However, the repeatability was good (RSDr of 8.78–9.96% for Ant and 6.43–11.9% for BaP), and the HorRat values were acceptable (1.56–1.94 for Ant and 1.10–1.45 for BaP). In all other cases, repeatability, reproducibility, and HorRat values were as follows: shrimp: RSDr 1.40–26.9%, RSDR 5.41–29.4%, HorRat: 0.22–1.34; mussel: RSDr 2.52–17.1%, RSDR 4.19–32.5%, HorRat: 0.17–1.13; and oyster: RSDr 3.12–22.7%, RSDR 8.41–31.8%, HorRat: 0.34–1.39. The results demonstrate that the method is fit-for-purpose to determine PAHs and their alkyl homologs in seafood samples. The method was approved by the Expert Review Panel on PAHs as the AOAC Official First Action Method 2014.08.

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