Search results for "Tungsten hexacarbonyl"
showing 5 items of 5 documents
Pentacyanopropenide group as ligand in organometallic chemistry. Crystal structure and electrochemical studies of (Et4N)[W(CO)5{(C(CN)2C(CN)C(CN)2}]
1999
Abstract The title complex has been obtained by reaction of the tetraethylammonium pentacyanopropenide with tungsten hexacarbonyl in acetone. Its crystal structure involves discrete [W(CO)5{C3(CN)5}]− anions in which the organic fragment is N-coordinated via one of the nitrogen atoms of a cyano group borne by one of the terminal carbon atoms of the allylic skeleton. The anion presents a distorted octahedral coordination with a W–N bond length [2.168(5) A] considerably longer than the W–C bond lengths [cis-W–C in the range 1.998(7)–2.068(4) A; trans-W–C 1.962(7) A]. Cyclic voltammograms of this complex, recorded in CH2Cl2 and CH3CN (Bu4NPF6 0.1 M), display a quasi-reversible reduction and ir…
WOx phase growth on SiO2/Si by decomposition of tungsten hexacarbonyl:Influence of potassium on supported tungsten oxide phases
2009
International audience; Synchrotron based photoemission spectroscopy was used to study the adsorption of tungsten hexacarbonyl on SiO2 surfaces modified by potassium. Results were compared with the ones obtained when no potassium was present. Experiments using W4f and Si2p intensities variations show that, at 140 K, the tungsten hexacarbonyl growth proceeds via a simultaneous multilayer mode for the two kinds of surfaces but with differences in compositions of growing layers. Indeed, it is evidenced that, even at cryogenic temperatures, the presence of potassium induces decomposition of a significant part of tungsten hexacarbonyl molecules through a strong interaction between tungsten and p…
From tungsten hexacarbonyl adsorption on TiO2(1 1 0) surface to supported tungsten oxide phases.
2008
Abstract Synchrotron-based photoemission spectroscopies were used to study the adsorption of tungsten hexacarbonyl on (1 1 0) TiO 2 surfaces: experiments using W4f and Ti2p intensities variations show that, at 140 K, the hexacarbonyl growth proceeds via a layer-by-layer mode. Moreover, it was evidenced using both core levels and valence band experiments that, after back to room temperature, W(CO) 6 desorbs without significant decomposition. However, low energy (500 eV) ion (Ar + ) irradiation can allow partial decomposition of tungsten hexacarbonyl molecules leading to sub-carbonyl tungsten molecules. The bonding of sub-carbonyl species to the TiO 2 surface was then stronger than the one of…
A tungsten oxide–lutetium bisphthalocyanine n–p–n heterojunction: from nanomaterials to a new transducer for chemo-sensing
2019
We report on a new hybrid heterojunction gas-sensitive device by combining a molecular material with a metal oxide. WO3 was synthesised via an aerosol-assisted chemical vapour deposition technique from a tungsten hexacarbonyl precursor. Onto an inorganic film, LuPc2 was vacuum evaporated. The morphology of the WO3–LuPc2 hybrid films is dominated by the morphological features of the tungsten oxide film, as shown by scanning electron microscopy and atomic force microscopy. Raman spectroscopy of the device confirms the presence of both materials. The non-linear I–V characteristics demonstrate the existence of an energy barrier at the interface between the inorganic and molecular materials. The…
Atomic layer deposition of WO3 thin films using W(CO)6 and O3 precursors
2012
Here we report a new atomic layer deposition (ALD) process for WO3 thin films based on W(CO)6 as a tungsten source and ozone as a source of oxygen. A narrow ALD temperature window is found at 195–205 °C for WO3 with a deposition rate of 0.23 A per cycle. As-deposited films are partially crystalline with root mean square (rms) roughness values of 4.7 nm for 90 nm thick films; annealing the films at 600–1000 °C under oxygen or nitrogen atmospheres enhances the degree of crystallinity considerably. Our results show that the straightforward ALD chemistry of carbonyl compounds and ozone is applicable to the deposition of WO3 thin films.