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The physisorption-based separation of CO2 from CO is an energy-efficient yet challenging approach to obtain pure CO. We have applied an intrinsically porous molecular crystal (PMC), assembled from the readily synthesized macrocyclic cyclotetrabenzoin acetate to the problem of CO2/CO separation. This nanoporous material possesses both kinetic (micropore) and thermodynamic (CO2–π and CO2–carbonyl interactions) factors needed for selective CO2 capture. The moderate CO2–adsorbent interaction allows easy regeneration needed for pressure swing adsorption (PSA). Both trace (1%) and bulk (50%) amounts of CO2 can be removed from CO2/CO gas mixtures in PSA processes. [ABSTRACT FROM AUTHOR]

An experimental plan is developed for measuring the effective hydrogen/deuterium steric kinetic effect (KIE), which is based on greater bowl depth and barrier to bowl inversion in sym-1,3,5,7,9-pentamanisyl-corannule when compared to corannulene. The results have shown the usefulness of the N-heterocyclic carbene (NHC) ligand even for the coupling reaction with multichlorides.

An efficient method is described to prepare symmetric 7,8,9,10-substituted fluoranthenes from the reaction of peri-diynes and alkynes catalyzed by Wilkinson's complex. The crystal structure of indenocorannulenes have helped in understanding the bowl-shaped geometry of these compounds and this new synthetic method has occurred under neutral conditions.

Dimethoate, one of the organophosphorus pesticides, was selectively determined by ion mobility spectrometry (IMS) along with the single and mixed alternate reagent ions. By doping ammonium, acetone, ethanol, ether, and methanol into the carrier gas, the best selective detection was obtained by the addition of ammonium having the highest proton affinity among these single alternate reagent ions. Three mixed alternate reagents including ammonium-acetone, ammonium-ether, and acetone-ether, which were also used to improve the selectivity, showed better results than that single-solvent dopants gained. The best resolution and the highest abundance of the dimethoate peak were observed in its IMS spectrum after the addition of the mixed ammonium-acetone among all the above-mentioned dopants. The relationship curves for the concentration of ammonium and mixed ammonium-acetone to the response of dimethoate were studied. Ammonium at [approximately]1.0 [[micro]gram]/L levels or 1.0 [[micro]gram]/L ammonium at plus acetone at [approximately]1.0[[micro]gram]/L levels exhibited the strongest response of dimethoate. In addition, the direct determination of dimethoate residues was compared to its selective detection with mixed ammonium-acetone as the alternate reagent ions in a field test. A model for the selective analysis of an analyte having middle proton affinity in mixed compounds is proposed.

The syntheses, crystal structures, ab initio density functional theory calculations and photophysical properties of 1,6-di-, 1,2,5,6-tetra-, and 1,3,5,7,9-pentaethynyl-substituted coraanulenes are described. Most of the aryl derivatives have exhibited high-quantum-efficiency solution luminescence and variable emission wavelengths that are dependent on the nature of the substitution.

The synthesis and structure of monodispersed single-walled carbon nanotubes (SWCNT) from per-ethynylcorannulenes are described using a solution-phase method. Cognates [C.sub.40[H.sub.10] are the first members in the series of 5-fold symmetric SWCNT and potential seed compounds for preparing monodisperse higher order SWCNT.

The synthetic methods and physical properties of molecule bowls based on the corannulene motif which was first characterized bowl-shaped polynuclear aromatic hydrocarbon (PAH) is presented. The molecule stacking and alignment of the bowl-shaped aromatic compounds in the solid state affect the dipoles and electronic properties.

A room-temperature light-driven molecular brake ( 1), consisting of a pentiptycene rotator, a 3,5-dinitrophenyl brake, and a photoisomerizable ethenyl spacer, is reported. The rotation rates of the rotator differ by about 9 orders of magnitude between the brake-on ( cis- 1) and brake-off ( trans- 1) states. [ABSTRACT FROM AUTHOR]

The article discusses the synthesis, structure, and isomerization of decapentynylcorannulene enediyne cyclization of isomers, which open a solution-phase method to the synthesis of monodispersed single-walled carbon nanotubes (SWCNT). Cognates can be viewed as the potential seed compounds for the preparation of monodisperse higher order SWCNT. It inferred that there would be good reasons to be optimistic on finding efficient conditions for solution-phase syntheses of SWCNTs.

The electrochemical CO 2 reduction reaction (CO 2 RR) using renewable electricity is one of the most promising strategies for reaching the goal of carbon neutrality. Multicarbonous (C 2+ ) products have broad applications, and ethanol is a valuable chemical and fuel. Many Cu-based catalysts have been reported to be efficient for the electrocatalytic CO 2 RR to C 2+ products, but they generally offer limited selectivity and current density toward ethanol. Herein, we proposed a silica-mediated hydrogen-bonded organic framework (HOF)-templated approach to preparing ultrahigh-density Cu single-atom catalysts (SACs) on thin-walled N-doped carbon nanotubes (TWN). The content of Cu in the catalysts prepared by this method could be up to 13.35 wt %. It was found that the catalysts showed outstanding performance for the electrochemical CO 2 RR to ethanol, and the Faradaic efficiency (FE) of ethanol increased with the increase in Cu-N 3 site density. The FE of ethanol over the catalysts with 13.35 wt % Cu could reach ∼81.9% with a partial current density of 35.6 mA cm -2 using an H-type cell, which is the best result for electrochemical CO 2 RR to ethanol to date. In addition, the catalyst could be stably used for more than 25 h. Experimental and density functional theory (DFT) studies revealed that the adjacent Cu-N 3 active sites (one Cu atom coordinates with three N) were the active sites for the reaction, and their high density was crucial for the high FE of ethanol because the adjacent Cu-N 3 sites with a short distance could promote the C-C coupling synergistically.

NDIR CO 2 gas sensors using a 10-cm-long gas channel and CMOS-compatible 12% doped ScAlN pyroelectric detector have previously demonstrated detection limits down to 25 ppm and fast response time of ∼2 s. Here, we increase the doping concentration of Sc to 20% in our ScAlN-based pyroelectric detector and miniaturize the gas channel by ∼65× volume with length reduction from 10 to 4 cm and diameter reduction from 5 to 1 mm. The CMOS-compatible 20% ScAlN-based pyroelectric detectors are fabricated over 8-in. wafers, allowing cost reduction leveraging on semiconductor manufacturing. Cross-sectional TEM images show the presence of abnormally oriented grains in the 20% ScAlN sensing layer in the pyroelectric detector stack. Optically, the absorption spectrum of the pyroelectric detector stack across the mid-infrared wavelength region shows ∼50% absorption at the CO 2 absorption wavelength of 4.26 μm. The pyroelectric coefficient of these 20% ScAlN with abnormally oriented grains shows, in general, a higher value compared to that for 12% ScAlN. While keeping the temperature variation constant at 2 °C, we note that the pyroelectric coefficient seems to increase with background temperature. CO 2 gas responses are measured for 20% ScAlN-based pyroelectric detectors in both 10-cm-long and 4-cm-long gas channels, respectively. The results show that for the miniaturized CO 2 gas sensor, we are able to measure the gas response from 5000 ppm down to 100 ppm of CO 2 gas concentration with CO 2 gas response time of ∼5 s, sufficient for practical applications as the average outdoor CO 2 level is ∼400 ppm. The selectivity of this miniaturized CO 2 gas sensor is also tested by mixing CO 2 with nitrogen and 49% sulfur hexafluoride, respectively. The results show high selectivity to CO 2 with nitrogen and 49% sulfur hexafluoride each causing a minimum ∼0.39% and ∼0.36% signal voltage change, respectively. These results bring promise to compact and miniature low cost CO 2 gas sensors based on pyroelectric detectors, which could possibly be integrated with consumer electronics for real-time air quality monitoring.

A series of diindeno[2,1- b :2',1'- h ]biphenylenes with open-shell singlet ground states and interesting properties were prepared. The studied compounds consist of p -quinodimethane moieties, which suffer from geometric perturbation with bond angles of around 90°. The substituent effects on structural parameters, local aromaticity, and properties were systematically explored.

The tea shrub is grown in long-standing orchards, an environment that is suitable for persistent weed growth, which is increasingly controlled by herbicides. Therefore, there is increasing concern that tea consumers may be exposed to herbicide residues. In this study, the levels of glufosinate-ammonium (GLU), glyphosate [ N -(phosphonomethyl) glycine; PMG], and its metabolite aminomethyl phosphoric acid (AMPA) were determined in tea samples by HPLC-MS/MS using several current purification methods and a new method that we developed herein. The matrix effect of our proposed method was between -27.3 and 27.7%, which was lower than that in other methods, indicating that this method effectively reduced the interference of tea matrix in the mass spectrometry process. This method was used to determine the levels of PMG, GLU, and AMPA in 780 samples, including six traditional Chinese teas (green tea, black tea, oolong tea, dark tea, white tea, and yellow tea) and a floral tea, from 14 provinces of China. Probability estimates showed that the 95 th percentile risk entropy values of the three pesticide residues were far below the acceptable risk level. The risk assessment results showed that exposure to PMG, GLU, and AMPA caused by drinking tea beverages poses no significant risk to human health.

The particulate contamination degree of aviation coolants (ACs) is overestimated commonly because the bubbles in ACs are erroneously recognized as particulate contaminants during the measurement process. In this work, the factors that influence the foam behavior and contamination degree of ACs are investigated. It is evidenced that the foam behavior of ACs is basically unaffected by the ratio of glycol to water of the base solution, which, however, is highly influenced by the organic additive. Also, the more the organic additive arranged at the gas-liquid interface, the lower the surface tension of glycol aqueous (GA) solution and the higher the contamination degree. Furthermore, the foam characteristics and contamination degree of ACs are highly affected by the working conditions, such as airflow, operating temperature, and gas pressure. Besides, the defoaming rate can be accelerated by adding an antifoaming agent or ultrasonic processing; however, the defoaming effect of the natural static method and pressuring positively treatment is disappointing. To further improve the defoaming effect, several efficient synergetic methods of defoaming have been proposed., Competing Interests: The authors declare no competing financial interest., (© 2020 American Chemical Society.)

Infrared gas sensors have been proven promising for broad applications in Internet of Things and Industrial Internet of Things. However, the lack of miniaturized light sources with good compatibility and tunable spectral features hinders their widespread utilization. Herein, a strategy is proposed to increase the radiated power from microelectromechanical-based thermal emitters by coating with graphene oxide (GO). The radiation can be substantially enhanced, which partially stems from the high emissivity of GO coating demonstrated by spectroscopic methods. Moreover, the sp 2 structure within GO may induce plasmons and thus couple with photons to produce blackbody radiation and/or new thermal emission sources. As a proof-of-concept demonstration, the GO-coated emitter is integrated into a multifunctional monitoring platform and evaluated for gas detection. The platform exhibits sensitive and highly selective detection toward CO 2 at room temperature with a detection limit of 50 ppm and short response/recovery time, outperforming the state-of-the-art gas sensors. This study demonstrates the emission tailorability of thermal emitters and the feasibility of improving the associated gas sensing property, offering perspectives for designing and fabricating high-end optical sensors with cost-effectiveness and superior performance.

The identification of novel succinate dehydrogenase (SDH) inhibitors represents one of the most attractive directions in the field of fungicide research and development. During our continuous efforts to pursue inhibitors belonging to this class, some structurally novel pyrazole-furan carboxamide and pyrazole-pyrrole carboxamide derivatives have been discovered via the introduction of scaffold hopping and bioisosterism to compound 1, a remarkably potent lead obtained by pharmacophore-based virtual screening. As a result of the evaluation against three destructive fungi, including Sclerotinia sclerotiorum, Rhizoctonia solani, and Pyricularia grisea, a majority of them displayed potent fungicidal activities. In particular, compounds 12I-i, 12III-f, and 12III-o exhibited excellent fungicidal activity against S. sclerotiorum and R. solani comparable to that of commercial SDHI thifluzamide and 1.

A series of 9,10-diarylphenanthrenes was prepared, and their structures and dynamic behaviors were both theoretically and experimentally investigated. A more twisted and crowded phenanthrene backbone was associated with a lower barrier to the rotation of an aryl group.

The self-assembly of the C38H14-buckybowl, a fragment bowl of the C70 fullerene, has been studied with scanning tunneling microscopy on the Cu(111) surface. Isolated molecules adsorb bowl opening-up with the center C6 ring parallel to the surface. In extended 2D islands, however, 1/3 of the molecules are oriented such that the bowl opening points down. From a detailed analysis of relative orientation of the molecules, the nature of intermolecular lateral interactions is identified. In densely packed islands, π-π bonding between convex sides of the bowls dominate, while π-H bonding between rim and convex sides plays the important role in small molecular 2D clusters.

Zethrene-based condensed arenes dinaphthozethrene and diindenozethrene were synthesized by oxidative cyclodehydrogenation and palladium-catalyzed cyclization of 7,14-diarylzethrenes, respectively. Their structures were analyzed by X-ray crystallography. The photophysical and electrochemical properties of these compounds were investigated.

Fluorenes and methylene-bridged polyarenes were easily and efficiently synthesized from haloarenes (or aryl triflates) and diarylethynes by a one-pot, two-step procedure. This protocol involves the palladium-catalyzed cycloisomerization and a subsequent base-mediated retro-aldol condensation. A major advantage is that the starting materials need not have ortho functional groups to complete the annulation. The backbone of the designed products was enlarged using dihaloarenes, highly π-conjugated haloarenes, or diarylalkynes. The mechanism of the formation of benzo[a]fluorene was investigated. The bowl-shaped structure of methylene-bridged indenocorannulene was verified by X-ray crystallography. The photophysical and electrochemical properties of the products thus prepared were investigated.