Search results for "PAPER"
showing 10 items of 2166 documents
4-[5-(4-Fluorophenyl)-1H-imidazol-4-yl]pyridine
2009
In the title compound, C(14)H(10)FN(3), the imidazole ring makes dihedral angles of 28.2 (1) and 36.60 (9)° with the pyridine ring and the 4-fluoro-phenyl ring, respectively. The pyridine ring forms a dihedral angle of 44.68 (9)° with the 4-fluoro-phenyl ring. Inter-molecular N-H⋯N hydrogen bonds are observed in the crystal structure.
4-(4-Fluorophenyl)-3-(pyridin-4-yl)-1-(2,4,6-trichlorophenyl)-1H-pyrazol-5-amine
2012
In the title compound, C20H12Cl3FN4, the pyrazole ring forms dihedral angles of 47.51 (9), 47.37 (9) and 74.37 (9)° with the directly attached 4-fluorophenyl, pyridine and 2,4,6-trichlorophenyl rings, respectively. Only one of the two amino H atoms is involved in hydrogen bonding. The crystal packing is characterized by N—H...N hydrogen bonds, which result in infinite chains parallel to the c axis.
4-(4-Fluorophenyl)-1-phenyl-3-(pyridin-4-yl)-1H-pyrazol-5-amine
2012
In the title compound, C20H15FN4, the pyrazole ring forms dihedral angles of 43.51 (6), 39.95 (6) and 32.23 (6)° with the directly attached 4-fluorophenyl, pyridine and phenyl rings, respectively. The crystal packing is stabilized by intermolecular N—H...N and N—H...F hydrogen bonds.
N-Benzyl-2,3,4,5,6-pentafluorobenzamide
2010
In the title compound, C14H8F5NO, the dihedral angle between the planes of the pentafluorophenyl and phenyl rings is 18.34 (5)°. An intermolecular N—H...O hydrogen bond between the amide groups connects these molecules to form an infinite chain through the crystal structure. One weak intermolecular C—H...O contact and one π–π interaction [centroid–centroid distance = 3.772 (3) Å] are also involved in crystal structure stabilization between the phenyl rings.
N-(4-Acetyl-3-methyl-1-phenyl-1H-pyrazol-5-yl)-N-methyl-2-(2-methyl-4-oxo-3,4-dihydroquinazolin-3-yl)benzamide
2013
In the title compound, C29H25N5O3, the dihedral angle between the benzene ring and the pendant quinazoline ring system (r.m.s. deviation = 0.036Å) is 87.60 (17)°. The equivalent angle between the pyrazole ring and the phenyl group is 70.0 (2)°. The dihedral angle between the benzene and pyrazole rings is 30.7 (2)° and overall, the molecular conformation approximates to a Z shape. A short intramolecular C—H...O contact occurs. In the crystal, the molecules are linked by Cπ—H...O-type hydrogen bonds and aromatic π–π stacking interactions [centroid–centroid distance = 3.860 (3) Å], generating a three-…
rac-Ethyl (2Z)-3-{2-[(Z)-4-ethoxy-4-oxobut-2-en-2-ylamino]cyclohexylamino}but-2-enoate
2011
The asymmetric unit of the title compound, C18H30N2O4, contains two independent molecules. In each molecule, the cyclohexane ring adopts a chair conformation with equatorial orientation of the substituents, and the conformation is stabilized by two intramolecular N—H...O hydrogen bonds, forming rings of S(6) graph-set motif. One ethoxy group and one ethyl group are disordered over two sets of sites with refined occupancy ratios of 0.704 (2):0.296 (2) and 0.505 (3):0.495 (3), respectively. In the crystal, a weak intermolecular C—H...O hydrogen interaction is observed, involving the O atom of the major component of the disordered eth…
Hydrogen and methane production in extreme thermophilic conditions in two-stage (upflow anaerobic sludge bed) UASB reactor system
2013
Abstract Two-stage hydrogen and methane production in extreme thermophilic (70 °C) conditions was demonstrated for the first time in UASB-reactor system. Inoculum used in hydrogen and methane reactors was granular sludge from mesophilic internal circulation reactor and was first acclimated for extreme thermophilic conditions. In hydrogen reactor, operated with hydraulic retention time (HRT) of 5 h and organic loading rate (OLR) of 25.1 kg COD/m 3 /d, hydrogen yield was 0.73 mol/mol glucose added . Methane was produced in second stage from hydrogen reactor effluent. In methane reactor operated with HRT of 13 h and OLR of 7.8 kg COD/m 3 /d, methane yield was 117.5 ml/g COD added . These resul…
Conformational equilibrium in supramolecular chemistry: Dibutyltriuret case
2015
The association of substituted benzoates and naphthyridine dianions was used to study the complexation of dibutyltriuret. The title molecule is the simplest molecule able to form two intramolecular hydrogen bonds. The naphthyridine salt was used to break two intramolecular hydrogen bonds at a time while with the use of substituted benzoates the systematic approach to study association was achieved. Both, titrations and variable temperature measurements shed the light on the importance of conformational equilibrium and its influence on association in solution. Moreover, the associates were observed by mass spectrometry. The DFT-based computations for complexes and single bond rotational barr…
Co-production of Hydrogen and Methane From the Organic Fraction of Municipal Solid Waste in a Pilot Scale Dark Fermenter and Methanogenic Biofilm Rea…
2018
The co-production of biohydrogen and methane from the organic fraction of municipal solid waste was investigated using a two-stage AD system, composed of a pilot scale dark fermenter (DF) and a continuous methanogenic biofilm reactor. From the DF process, a biohydrogen yield of 41.7 (± 2.3) ml H2/gVSadded was achieved. The liquid DF effluent (DFE) was rich in short chain volatile fatty acids, i.e., mainly acetic and butyric acid. The DFE was valorized by producing methane in the methanogenic biofilm reactor. Two methanogenic biofilm reactors were used to assess the biotic and abiotic role of the DFE on the performance of the reactors. Regardless of the different DFE feeding (i.e., biotic an…
Singlet‐Contrast Magnetic Resonance Imaging: Unlocking Hyperpolarization with Metabolism
2020
Abstract Hyperpolarization‐enhanced magnetic resonance imaging can be used to study biomolecular processes in the body, but typically requires nuclei such as 13C, 15N, or 129Xe due to their long spin‐polarization lifetimes and the absence of a proton‐background signal from water and fat in the images. Here we present a novel type of 1H imaging, in which hyperpolarized spin order is locked in a nonmagnetic long‐lived correlated (singlet) state, and is only liberated for imaging by a specific biochemical reaction. In this work we produce hyperpolarized fumarate via chemical reaction of a precursor molecule with para‐enriched hydrogen gas, and the proton singlet order in fumarate is released a…