Bynumpeters9265

The concept of alkynophilicity is revisited with group 13 MX3 metal salts (M = In, Ga, Al, B; X = Cl, OTf) using M06-2X/6-31+G(d,p) calculations. This study aims at answering why some of these salts show reactivity toward enynes that is similar to that observed with late-transition-metal complexes, notably Au(I) species, and why some of them are inactive. For this purpose, the mechanism of the skeletal reorganization of 1,6-enynes into 1-vinylcyclopentenes has been computed, including monomeric ("standard") and dimeric (superelectrophilic) activation. Those results are confronted with deactivation pathways based on the dissociation of the M-X bond. The role of the X ligand in the stabilization of the intermediate nonclassical carbocation is revealed, and the whole features required to make a good π-Lewis acid are discussed.Ground-level ozone (O3) is one of the main airborne pollutants detrimental to human health and ecosystems. However, the designed synthesis of high-performance O3 elimination catalysts suitable for broadly variable air compositions, especially a variable water vapor content, remains daunting. Herein, we report a new manganese-based metal organic framework, [Mn3(μ3-OH)2(TTPE)(H2O)4]·2H2O (H4TTPE = 1,1,2,2-tetrakis(4-(2H-tetrazol-5-yl)phenyl) ethane), denoted as ZZU-281. ZZU-281 catalyzes O3 decomposition with a nearly constant 100% working efficiency over the entire humidity range from dry (≤5% relative humidity (RH)) to high humidity (90% RH). learn more We found that the maintainable coordinated water molecules and OH groups are activated by Mn2+, becoming active sites for O3 transfer to O2 with a low activation energy. The unique open channels, water retainability, and water stability of ZZU-281 further support the high catalytic performance. This work opens a new avenue for designing efficient catalysts for O3 elimination in practice.The atmospheric chemistry of isoprene has broad implications for regional air quality and the global climate. Allylic radicals, taking 13-17% yield in the isoprene oxidation by •Cl, can contribute as much as 3.6-4.9% to all possible formed intermediates in local regions at daytime. Considering the large quantity of isoprene emission, the chemistry of the allylic radicals is therefore highly desirable. Here, we investigated the atmospheric oxidation mechanism of the allylic radicals using quantum chemical calculations and kinetics modeling. The results indicate that the allylic radicals can barrierlessly combine with O2 to form peroxy radicals (RO2•). Under ≤100 ppt NO and ≤50 ppt HO2• conditions, the formed RO2• mainly undergo two times "successive cyclization and O2 addition" to finally form the product fragments 2-alkoxy-acetaldehyde (C2H3O2•) and 3-hydroperoxy-2-oxopropanal (C3H4O4). The presented reaction illustrates a novel successive cyclization-driven autoxidation mechanism. The formed 3-hydroperoxy-2-oxopropanal product is a new isomer of the atmospheric C3H4O4 family and a potential aqueous-phase secondary organic aerosol precursor. Under >100 ppt NO condition, NO can mediate the cyclization-driven autoxidation process to form C5H7NO3, C5H7NO7, and alkoxy radical-related products. The proposed novel autoxidation mechanism advances our current understanding of the atmospheric chemistry of both isoprene and RO2•.Quantum materials have attracted much attention in recent years due to their exotic and incredible properties. Among them, van der Waals materials stand out due to their weak interlayer coupling, providing easy access to manipulating electrical and optical properties. Many fascinating electrical, optical, and magnetic properties have been reported in the moiré superlattices, such as unconventional superconductivity, photonic dispersion engineering, and ferromagnetism. In this review, we summarize the methods to prepare moiré superlattices in the van der Waals materials and focus on the current discoveries of moiré pattern-modified electrical properties, recent findings of atomic reconstruction, as well as some possible future directions in this field.The motive of this study is the rapid increase of industrial and domestic wastewater application for the growth of agricultural crops, which is closely associated with human health. In this study, the accumulation of eight heavy metals (Zn, Cu, Fe, Mn, Pb, Cr, Ni, and Cd) in the edible parts of five different species of common vegetables-cauliflower, bitter gourd, radish, pumpkin, and apple gourd-irrigated by two different water irrigation sources (wastewater/freshwater) grown in Pakistan's industrial and agricultural city Gujranwala and human health risks associated with the consumption of vegetables were evaluated. The mean concentration of each metal (Zn, Cu, Fe, Mn, Pb, Cr, Ni, and Cd) in five selected freshwater irrigated vegetables was observed as 48.91, 38.47, 133, 87.5, 4.62, 0.92, 1.46, and 0.36 mg/kg, respectively, while the mean concentration of each corresponding metal in wastewater irrigated vegetables was found to be 59.2, 49.5, 188, 90.9, 6.08, 2.66, 3.98, and 1.76 mg/kg, respectively. The estigenic and non-carcinogenic) would be posed to the adult population through the consumption of wastewater irrigated vegetables comparatively.Per- and polyfluoroalkyl substances (PFASs) were analyzed in outdoor (n = 101) and indoor dust (n = 43, 38 paired with outdoors) samples across mainland China. From 2013 to 2017, the median concentration of ∑PFASs in outdoor dust tripled from 63 to 164 ng/g with an elevated contribution of trifluoroacetic acid and 62 fluorotelomer alcohol. In 2017, the indoor dust levels of ∑PFASs were in the range 185-913 ng/g, which were generally higher than the outdoor dust levels (105-321 ng/g). Emerging PFASs were found at high median levels of 5.7-97 ng/g in both indoor and outdoor dust samples. As first revealed by the total oxidized precursors assay, unknown perfluoroalkyl acid (PFAA)-precursors contributed 37-67 mol % to the PFAS profiles in indoor dust samples. A great proportion of C8 PFAA-precursors were precursors for perfluorooctanesulfonic acid, while C6 and C4 PFAA-precursors were mostly fluorotelomer based. Furthermore, daily perfluorooctanoic acid (PFOA) equivalent intakes of PFAAs (C4-C12) mixtures via indoor dust were first estimated at 1.