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Gavin O Jones, Zachary J Krebs
Thorough computational studies were performed on mechanisms and energies for the thermal trimerizations of neutral or electron-rich acetylenes used as cross-linkers in organic hard-masks for lithography applications. These studies indicate that the operative mechanism proceeds through initial cyclobutadiene formation via a biradical mechanism. Cyclobutadienes form Dewar benzenes via Diels-Alder cycloadditions, or biradical processes, or both, before producing benzenes by electrocyclic ring-opening reactions...
September 22, 2017: Organic & Biomolecular Chemistry
Qian Rong, Yumin Zhang, Chao Wang, Zhongqi Zhu, Jin Zhang, Qingju Liu
Ag-LaFeO3 molecularly imprinted polymers (ALMIPs) were fabricated, which provided special recognition sites to methanol. Then ALMIPs fiber 1, fiber 2 and fiber 3 were prepared using filter paper, silk and carbon fibers template, respectively. Based on the observation of X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and Nitrogen adsorption surface area analyzer (BET), the structure, morphology and surface area of the fibers were characterized. The ALMIPs fibers (fiber 1, fiber 2 and fiber 3) show excellent selectivity and good response to methanol...
September 21, 2017: Scientific Reports
Daniel Bouchard, Philipp Wanner, Hong Luo, Patrick W McLoughlin, James K Henderson, Robert J Pirkle, Daniel Hunkeler
The methodology of the solvent-based dissolution method used to sample gas phase volatile organic compounds (VOC) for compound-specific isotope analysis (CSIA) was optimized to lower the method detection limits for TCE and benzene. The sampling methodology previously evaluated by [1] consists in pulling the air through a solvent to dissolve and accumulate the gaseous VOC. After the sampling process, the solvent can then be treated similarly as groundwater samples to perform routine CSIA by diluting an aliquot of the solvent into water to reach the required concentration of the targeted contaminant...
August 24, 2017: Journal of Chromatography. A
Mostafa Leili, Sima Farjadfard, George A Sorial, Bahman Ramavandi
A biofiltration system was developed to treat benzene, toluene, ethylbenzene, and xylene (BTEX) and Hg° vapour from a petrochemical waste stream during overhaul maintenance. The biofilter compost bed was inoculated with a microbial consortium provided by a petrochemical wastewater treatment plant. The effect of the a BTEX concentration (192.6-973.8 g/m(3)h) and empty bed residence time (EBRT) of 20-100 s were studied under the conditions of steady state, transient, shock BTEX-loading, and off-restart. The findings revealed that during a biofilter start-up, an increase in the influent BTEX concentration to around 334...
September 18, 2017: Journal of Environmental Management
Qiang Meng, Fei Chen, Wei Yu, Bing Han
A novel method for the synthesis of trifluoromethyl-containing 1'H-spiro[azirine-2,4'-quinolin]-2'(3'H)-ones by a CF3-radical-triggered tandem reaction of benzene-linked 1,7-enynes is described. This protocol utilizes 1-trifluoromethyl-1,2-benziodoxole as the trifluoromethylating reagent and TMSN3 as the aminating reagent. By this method, various potentially bioactive trifluoromethylated 1'H-spiro[azirine-2,4'-quinolin]-2'(3'H)-ones were facilely synthesized via a radical cascade process.
September 21, 2017: Organic Letters
Takumi Ishizuka, Pei-Yan Zhao, Hong-Liang Bao, Yan Xu
In the present study, we developed a multi-functional guanine derivative, (8F)G, as a G-quadruplex stabilizer, a fluorescent probe for the detection of G-quadruplex formation, and a (19)F sensor for the observation of the G-quadruplex. We demonstrate that the functional nucleoside bearing a 3,5-bis(trifluoromethyl)benzene group at the 8-position of guanine stabilizes the DNA G-quadruplex structure and fluoresces following the G-quadruplex formation. Furthermore, we show that the functional sensor can be used to directly observe DNA G-quadruplexes by (19)F-NMR in living cells...
September 21, 2017: Analyst
Jim Simpson, Shaaban K Mohamed, Adel A Marzouk, Antar A Abdelhamid, Mustafa R Albayati
The title compound, C24H21N3O3, crystallizes with two unique but closely r.m.s. overlay fit = 0.215 Å) comparable mol-ecules (1 and 2) in the asymmetric unit of the triclinic unit cell. In molecule 1, the dihedral angles between the central imidazlole ring and the benzene-ring substituents are 42.51 (9), 45.41 (9) and 56.92 (8)°, respectively. Comparable data for molecule 2 are 39.36 (10), 34.45 (11) and 60.34 (8)°, respectively. The rings at the 2-positions carry p-nitro substituents that subtend dihedral angles of 12...
September 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
Saray Argibay-Otero, Ezequiel M Vázquez-López
The structure of the title compound, C11H15N3OS, shows the flexibility due to the methyl-ene group at the thio-amide N atom in the side chain, resulting in the mol-ecule being non-planar. The dihedral angle between the plane of the benzene ring and that defined by the atoms of the thio-semicarbazide arm is 79.847 (4)°. In the crystal, the donor-acceptor hydrogen-bond character of the -OH group dominates the inter-molecular associations, acting as a donor in an O-H⋯S hydrogen bond, as well as being a double acceptor in a centrosymmetric cyclic bridging N-H⋯O,O' inter-action [graph set R2(2)(4)]...
September 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
Wannur Sofiasalamah Khairiah A Rahman, J Ahmad, Siti Nadiah Abdul Halim, Mukesh M Jotani, Edward R T Tiekink
The full mol-ecule of the binuclear title compound, [Cd2Cl2(C6H8O4)(C6H8N2)2(H2O)2], is generated by the application of a centre of inversion located at the middle of the central CH2-CH2 bond of the adipate dianion; the latter chelates a Cd(II) atom at each end. Along with two carboxyl-ate-O atoms, the Cd(II) ion is coordinated by the two N atoms of the chelating benzene-1,2-di-amine ligand, a Cl(-) anion and an aqua ligand to define a distorted octa-hedral CdClN2O3 coordination geometry with the monodentate ligands being mutually cis...
September 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
Peter W R Corfield, Richard A Kershaw
The crystal structures of the trans-fused compound potassium trans-bi-cyclo-[5.1.0]octane-4-carboxyl-ate monohydrate, K(+)·C9H13O2(-)·H2O, (I), and of cis-bi-cyclo-[5.1.0]octan-4-yl 4-bromo-benzene-sulfonate, C14H17BrO3S, (II), have been determined. Compound (I) represents the smallest trans-fused cyclo-propane structure known to date, and features the expected shortening of the bridging C-C bond relative to the other cyclo-propane bond lengths, in contrast to the cis-fused system, (II), where all of the cyclo-propane bond lengths are the same...
September 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
Wenju Liu, Qiliang Chen, Linda Yu
The title salt, C13H22NO3(+)·C7H5O2(-), comprises one salbutamol cation {sys-tematic name: 4-[2-(tert-butyl-aza-nium-yl)-1-hy-droxy-eth-yl]-2-(hy-droxy-meth-yl)phenol} and a benzoate anion. The cation shows disorder of the hy-droxy group [occupancy ratio 0.738 (3):0.262 (3)] at the stereogenic C atom. The non-planar benzoate anion [the dihedral angle between the benzene ring and the carboxyl group is 11.30 (8)°] is linked to the salbutamol cation by a medium-strength O-H⋯O hydrogen bond. Other inter-molecular O-H⋯O and N-H⋯O hydrogen bonds of weaker nature give rise to [001] chains...
September 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
Yousef M Hijji, Rajeesha Rajan, Said Mansour, Hamdi Ben Yahia
In the title compound, C12H9NO3, the benzoate and furan rings are almost coplanar, making a dihedral angle of 11.68 (9)°. The twist angle between the -COO group and the benzene ring is only 2.79 (16)°. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, forming chains along [100]. The mol-ecules stack in a herringbone fashion and inversion-related chains are linked by offset π-π inter-actions [inter-centroid distance = 3.931 (1) Å], forming ribbons propagating along the a-axis direction...
September 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
Hyunjin Park, Jineun Kim, Hojae Chiang, Tae Ho Kim
The title compound, C16H14F5N5O5S [systematic name: 2-(2,2-di-fluoro-eth-oxy)-N-(5,8-dimeth-oxy-1,2,4-triazolo[1,5-c]pyrimidin-2-yl)-6-(tri-fluoro-meth-yl)benzene-sulfonamide], is used as a herbicide. The asymmetric unit of this structure comprises two independent mol-ecules, A and B. The dihedral angles between the ring planes of the triazolo-pyrimidine ring systems and the benzene rings are 68.84 (7)° for A and 68.05 (6)° for B. In the crystal, weak inter-molecular π-π inter-actions, with centroid-centroid separations of 3...
September 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
Jing Zhu, Guo Hui Hou, Qian Li, Fu Wei Zheng, Hong Liang Wei, Hui Juan Chu, Gang Wang, Juan He, Ling Bo Qu
The title compound, C48H42N3O18P3, achieved in a two-step synthesis, comprises a cyclo-triphosphazene core and six 4-meth-oxy-carbonyl-phen-oxy groups. Each P atom is attached to two substituents located up and down with respect to the plane of the phosphazene ring, the central P3N3 ring having a twist-boat conformation. The three O/P/O planes and five of the six benzene rings are nearly perpendicular to the mean plane through the phosphazene ring [dihedral angles = 82.98 (8)-88.92 (8)°], while the remaining benzene ring forms a dihedral angle of 25...
July 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
Julio Zukerman-Schpector, Fabricia H Sugiyama, Ariel L L Garcia, Carlos Roque D Correia, Mukesh M Jotani, Edward R T Tiekink
The title compound, C14H17NO4, features an epoxide-O atom fused to a pyrrolidyl ring, the latter having an envelope conformation with the N atom being the flap. The 4-meth-oxy-phenyl group is orthogonal to [dihedral angle = 85.02 (6)°] and lies to the opposite side of the five-membered ring to the epoxide O atom, while the N-bound ethyl ester group (r.m.s. deviation of the five fitted atoms = 0.0187 Å) is twisted with respect to the ring [dihedral angle = 17.23 (9)°]. The most prominent inter-actions in the crystal are of the type methine-C-H⋯O(carbon-yl) and these lead to the formation of linear supra-molecular chains along the c axis; weak benzene-C-H⋯O(epoxide) and methine-C-H⋯O(meth-oxy) inter-actions connect these into a three-dimensional architecture...
July 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
Hemant P Yennawar, Ryan Fox, Quentin J Moyer, Ziwei Yang, Lee J Silverberg
In the racemic title compound, C20H15NO2S, the planes of the two phenyl substituents form dihedral angles of 48.97 (15) and 69.26 (15)° with that of the fused benzene ring of the parent benzo-thia-zine ring, while the heterocyclic thia-zine ring exhibits a screw-boat pucker. The O atom on the S atom of the ring is pseudo-axial on the thia-zine ring and trans to the 2-phenyl group. In the crystal, mol-ecules are arranged in layers in the ac plane, the layers being linked across b through inter-molecular C-H⋯O hydrogen-bonding inter-actions...
July 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
John Nicolson Low, Ligia R Gomes, Alexandra Gaspar, Fernanda Borges
Herein, the synthesis and crystal structure of 7-hy-droxy-3-(2-meth-oxy-phen-yl)-2-tri-fluoro-meth-yl-4H-chromen-4-one, C17H11F3O4, are reported. This isoflavone is used as a starting material in the preparation an array of potent and competitive FPR antagonists. The pyran ring significantly deviates from planarity and the dihedral angle between the benzo-pyran mean plane and that of the exocyclic benzene ring is 88.18 (4)°. In the crystal, O-H⋯O hydrogen bonds connect the mol-ecules into C(8) chains propagating in the [010] direction...
July 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
A K Bauri, S Foro, A F M M Rahman
In the title compound, tetra-hydro-seselin, C14H16O3, a pyran-ocoumarin [systematic name: 8,8-dimethyl-3,4,9,10-tetra-hydro-2H,8H-pyrano[2,3-f]chromen-2-one] obtained from the hydrogenation of seselin in the presence of Pd/C in MeOH at room temperature, the dihedral angle between the central benzene ring and the best planes of the outer fused ring systems are 6.20 (7) and 10.02 (8)°. In the crystal, mol-ecules show only very weak inter-molecular C-H⋯O inter-actions.
July 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
Mingjie Xie, Xi Chen, Michael D Hays, Michael Lewandowski, John H Offenberg, Tadeusz Edward Kleindienst, Amara Holder
Secondary organic aerosol (SOA) might affect the atmospheric radiation balance through absorbing light at shorter visible and UV wavelengths. However, the composition and optical properties of light-absorbing SOA is poorly understood. In this work, SOA filter samples were collected during individual chamber experiments with three biogenic and eight aromatic volatile organic compound (VOC) precursors in the presence of NOX and H2O2. Compared with the SOA generated using the aromatic precursors, biogenic SOA in general exhibits negligible light absorption above 350 nm; the aromatic SOA generated in the presence of NOX showed stronger light absorption than that generated with H2O2...
September 20, 2017: Environmental Science & Technology
Paola Romagnoli, Francesca Vichi, Catia Balducci, Andrea Imperiali, Mattia Perilli, Lucia Paciucci, Francesco Petracchini, Angelo Cecinato
Particulate polycyclic aromatic hydrocarbons (PAHs), n-alkanes, and gaseous pollutants were collected from the harbor and the urban area of Crotone (Southern Italy) in October 2015. The atmospheric concentrations of organic substances associated to PM10 were determined daily, while gaseous pollutants (BTEX, O3, SO2, NOx, NO2, and NH3) were monitored on monthly basis by means of diffusive sampling. Total PAHs reached, on the average, 1.56 ± 0.72, 0.33 ± 0.14, and 0.59 ± 0.37 ng/m(3) at the urban monitoring stations (Fiore, Fermi) and at the harbor, respectively...
September 19, 2017: Environmental Science and Pollution Research International
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