Search results for "Surfaces"
showing 10 items of 2837 documents
Epoxidation of stilbene using supported gold nanoparticles: cumyl peroxyl radical activation at the gold nanoparticle surface.
2014
The catalytic epoxidation of cis-stilbene using cumene as a solvent in the presence of supported gold nanoparticles (AuNP) yields a mixture of cis and trans-stilbene oxides. EPR and product distribution studies support a new mechanistic proposal where oxygen centred radicals activate the AuNP surface and form active surface oxygen species responsible for the epoxidation products.
Cyanide-bridged Fe(III)–Co(II) bis double zigzag chains with a slow relaxation of the magnetisation
2003
Reaction of [FeIII(bipy)(CN)4]¯ with fully solvated MII cations [M = Co (1) and Mn (2)] produces the isostructural bis double zigzag chains [[FeIII(bipy)(CN)4]2MII(H2O)]·MeCN·1/2H2O; 1 exhibits intrachain ferromagnetic and interchain antiferromagnetic couplings, slow magnetic relaxation and hysteresis effects. Luminita Marilena, Toma, Luminita.Toma@uv.es ; Lescouezec, Alain Francois Rodri, Alain.Lescouezec@uv.es ; Lloret Pastor, Francisco, Francisco.Lloret@uv.es ; Julve Olcina, Miguel, Miguel.Julve@uv.es
Photoinduced HS state in the first spin-crossover chain containing a cyanocarbanion as bridging ligand
2009
A new polymeric approach, based on cyanocarbanion ligands, for the design of spin crossover (SCO) compounds led us to the compound [Fe(abpt)2(tcpd)] (1) (tcpd^2 = (C[C(CN)2|3)^2 , abpt = 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole) which has been characterised as the first SCO molecular chain involving a cyanocarbanion as bridging ligand. Gomez Garcia, Carlos Jose, Carlos.Gomez@uv.es
Blending pieces of Dupin cyclides for 3D modeling and reconstruction : study in the space of spheres
2013
The thesis deals with the blending of canal surfaces in geometric modeling using pieces of Dupin Cyclides. We try to solve a problem of reconstructing real parts manufactured and controlled by the CEA of Valduc. Using the space of spheres in which we can manipulate both points, spheres and canal surfaces, we simplify some problems. This space is represented by a 4-dimensional quadric in a 5-dimensional space, equipped with the Lorentz form, it is the Lorentz space. In the space of spheres, problems of blending canal surfaces by pieces of Dupin cyclides are simplified in linear problems. We give algorithms to make such blends using the space of spheres and after we come back to 3 dimensions …
Model for Solid State Voltammetry of Zeolite-Associated Species
2004
The electrochemical reduction/oxidation of zeolite-associated species is described from the model of Lovric and Scholz for redox conductive microcrystals and the model of Andrieux and Saveant for redox polymers. It is assumed that the reaction starts at the three-phase boundary between electrode, zeolite particle, and electrolyte. From this point, the reaction zone grows while electrons and charge-balancing cations diffuse perpendicularly along the zeolite. As a result, at short times, a Cottrell-type behavior, controlled by the diffusion of electrolyte countercations in the zeolite can be expected. At larger times, a thin-layer response in which electron hopping between adjacent redox site…
Fluorescent Sensing of Maleate versus Fumarate by a Neutral Cyclohexane Based Thiourea Receptor.
2006
A new cyclohexyl based fluorescent anion receptor, is able to recognize maleate versus fumarate both as their TMA salts. Costero Nieto, Ana Maria, Ana.Costero@uv.es ; Colera Llavata, Manuel, Manuel.Colera@uv.es ; Gaviña Costero, Pablo, Pablo.Gavina@uv.es ; Gil Grau, Salvador, Salvador.Gil@uv.es
Asymmetric synthesis of cyclopentanes bearing four contiguous stereocenters via an NHC-catalyzed Michael/Michael/esterification domino reaction.
2016
An NHC-catalyzed Michael/Michael/esterification domino reaction via homoenolate/enolate intermediates for the asymmetric synthesis of tetrasubstituted cyclopentanes is described.
Enantiocontrol in the intermolecular cyclopropanation reaction catalyzed by dirhodium(II) complexes with ortho-metalated aryl phosphine ligands
2001
(P) and (M) dirhodium(II) complexes with ortho-metalated aryl phosphines are assessed as chiral catalysts in the enantioselective cyclopropanation of styrenes by ethyl diazoacetate; enantioselectivities up to 91% and up to 87%, respectively, for cis- and trans-2-arylcyclopropanecarboxylates are observed. Barberis, Mario, Mario.Barberis@uv.es ; Lahuerta Peña, Pascual, Pascual.lahuerta@uv.es ; Perez Prieto, Julia, Julia.Perez@uv.es ; Sanau Torrecilla, Mercedes, Mercedes.Sanau@uv.es
Enantio- and diastereocontrol in intermolecular cyclopropanation reaction of styrene catalyzed by dirhodium(II) complexes with bulky ortho-metalated …
2004
Enantiomerically pure dirhodium(II) complexes with ortho-metalated p-substituted aryl phosphines have been shown to be enantio- and diastereoselective in the cyclopropanation of styrene by ethyl diazoacetate. Enantioselectivities up to 91% and diastereoselectivities up to 90% are observed for ethyl cis-2-phenylcyclopropanecarboxylate. Estevan Estevan, Francisco, Francisco.Estevan@uv.es ; Lahuerta Peña, Pascual, Pascual.lahuerta@uv.es ; Lloret Fillol, Julio, Julio.Lloret@uv.es ; Sanau Torrecilla, Mercedes, Mercedes.Sanau@uv.es ; Ubeda Picot, M Angeles, Angeles.Ubeda@uv.es ; Vila Gomez, Jaume Llorenc, Jaume.Vila@uv.es
Monolayer Formation of Molybdenum Carbonyl on Cu(111) Revealed by Scanning Tunneling Microscopy and Density Functional Theory
2012
International audience; Molybdenum carbonyl Mo(CO)(6) was adsorbed on the Cu(111) surface at 160 K in the monolayer coverage range and studied by scanning tunneling microscopy. A well-ordered monolayer of hexacarbonyl molecules was observed experimentally for the first time. The monolayer has a hexagonal structure compatible with a (root 7 x root 7)R19 superlattice on the copper (111) plane. The arrangement and orientation of the molecules on the surface were determined by density functional theory calculations, including van der Waals interactions. The comparison of adsorption and cohesive energies reveals that the molecule-substrate interaction is stronger than the intermolecular one, whi…