2,3-Dibromo-1,3-bis­(4-fluoro­phen­yl)propan-1-one

In the title compound, C15H10Br2F2O, the dihedral angle between the two 3-fluoro-substituted benzene rings is 5.7 (5)°. The two bromine substituents on the chalcone moiety are close to anti as the Br—C—C—Br torsion angle is 176.9 (7)°. Weak C—Br⋯π inter­actions may contribute to the crystal stability

(1E)-1-(3-Bromo­phen­yl)ethanone 2,4-di­nitro­phenyl­hydrazone

The title compound, C14H11BrN4O4, contains 3-bromo­phenyl and 2,4-dinitro­phenyl groups on opposite sides of a hydrazone unit and crystallizes with two mol­ecules in the asymmetric unit. The dihedral angles between the two ring systems in each mol­ecule are 2.0 (1) and 2.5 (4)°. Weak C—H⋯O hydrogen bonds and weak π–π stacking inter­actions [centroid–centroid distance = 3.7269 (14) Å] help to establish the packing. Intra­molecular N—H⋯O hydrogen bonds are also observed. On one of the rings, the Br atom is disordered over two equivalent positions of the phenyl ring [occupancy ratio 0.8734 (10):0.1266 (10)

Water-gas-shift over metal-free nanocrystalline ceria: an experimental and theoretical study

A tandem experimental and theoretical investigation of a mesoporous ceria catalyst reveals the properties of the metal oxide are conducive for activity typically ascribed to metals, suggesting reduced Ce3+ and oxygen vacancies are responsible for the inherent bi-functionality of CO oxidation and dissociation of water required for facilitating the production of H-2. The degree of reduction of the ceria, specifically the (100) face, is found to significantly influence the binding of reagents, suggesting reduced surfaces harbor the necessary reactive sites. The metal-free catalysis of the reaction is significant for catalyst design considerations, and the suite of in situ analyses provides a comprehensive study of the dynamic nature of the high surface area catalyst system. This study postulates feasible improvements in catalytic activity may redirect the purpose of the water-gas shift reaction from CO purification to primary hydrogen production.Peer ReviewedPostprint (author's final draft

In situ characterization of mesoporous Co/CeO2 catalysts for the high-temperature water-gas shift

Mesoporous Co/CeO2 catalysts were found to exhibit significant activity for the high-temperature water-gas shift (WGS) reaction with cobalt loadings as low as 1 wt %. The catalysts feature a uniform dispersion of cobalt within the CeO2 fluorite type lattice with no evidence of discrete cobalt phase segregation. In situ XANES and ambient pressure XPS experiments were used to elucidate the active state of the catalysts as partially reduced cerium oxide doped with oxidized cobalt atoms. In situ XRD and DRIFTS experiments suggest facile cerium reduction and oxygen vacancy formation, particularly with lower cobalt loadings. In situ DRIFTS analysis also revealed the presence of surface carbonate and bidentate formate species under reaction conditions, which may be associated with additional mechanistic pathways for the WGS reaction. Deactivation behavior was observed with higher cobalt loadings. XANES data suggest the formation of small metallic cobalt clusters at temperatures above 400 °C may be responsible. Notably, this deactivation was not observed for the 1% cobalt loaded catalyst, which exhibited the highest activity per unit of cobalt.Peer ReviewedPostprint (author's final draft

3,5-Bis(4-fluoro­phen­yl)-1-phenyl-4,5-dihydro-1H-pyrazole

In the title compound, C21H16F2N2, the dihedral angle between the fluoro­phenyl groups is 66.34 (8)°, and the dihedral angle between the envelope-configured pyrazole group (N/N/C/C/C) and the benzene ring is 11.50 (9)°. The dihedral angles between the benzene and the two fluoro-substituted phenyl groups are 77.7 (6) and 16.7 (5)°. Weak C—H⋯π interactions contribute to the stability of the crystal structure

Vapor-Phase Oxidation of Benzyl Alcohol Using Manganese Oxide Octahedral Molecular Sieves (OMS-2)

Vapor-phase selective oxidation of benzyl alcohol has been accomplished using cryptomelane-type manganese oxide octahedral molecular sieve (OMS-2) catalysts. A conversion of 92% and a selectivity to benzaldehyde of 99% were achieved using OMS-2. The role played by the oxidant in this system was probed by studying the reaction in the absence of oxidant. The natures of framework transformations occurring during the oxidation reaction were fully studied using temperature-programmed techniques, as well as in situ X-ray diffraction under different atmospheres

Studies of Metal Oxide Nanomaterials: Applications in Energy & Catalysis

Archival abstract submitte

N-(4-Bromophenyl)acetamide: a new polymorph

A new polymorph of the title compound, C8H8BrNO, has been determined at 173 K in the space group P21/c. The previous room-temperature structure was reported to crystallize in the orthorhombic space group Pna21 [Andreetti et al. (1968). Acta Cryst. B24, 1195–1198]. In the crystal, molecules are linked by N—H...O hydrogen bonds forming chains along [010]. Weak C—H...π interactions are also present

(\it E)-3-(4-Meth\-oxy\-phen\-yl)-1-4-(piperidin-1-yl)phen{\-}ylprop-2-en-1-one

The piperidine ring in the title compound, C\sb 21H\sb 23NO\sb 2, is in a slightly distorted chair conformation. The dihedral angle between the two benzene rings is 5.6(4)\circ. The dihedral angles between the propenone unit and the benzene and meth\-oxy-substituted benzene rings are 5.6(7) and 10.7(8)\circ, respectively. Weak inter\-molecular C—-H⋅sO hydrogen bonds and weak C—-H⋅sπ inter\-actions contribute to the stability of the crystal structure