Tungsten tetrachloride

In a dry box, an oven-dried 500-mL three-necked round-bottomed flask equipped with an N2 gas inlet, a precision mechanical stirrer, and a stopper is charged with 39.66 g (100 mmol) of WC16 and 18 g (51 mmol) of W(CO)6. The sealed flask is removed from the dry box, connected to a source of prepurified N2, and bubbler for pressure release. The stopper is replaced with a rubber septum and 300 mL of purified chlorobenzene is added via cannula techniques. Carbon monoxide evolution starts immediately. 

After the solvent is added, the septum is replaced with a reflux condenser, topped with an N2-CO gas outlet, which is connected to a mineral oil bubbler. The reaction mixture is stirred at reflux for 12 h, and a slow N2 purge is maintained throughout this period. After cooling to room temperature, the gray-green powder is isolated by filtration, washed with 2 x 50 mL of fresh chlorobenzene, followed by 4 x 50 mL of hexane, and dried in vacuo (10 storr, 25 °C, 8h). It is important to free the product of all traces of chlorobenzene in order to obtain clean reductions in the following syntheses. Yield 47 g (or 96% based on WC16). 

Tungsten tetrachloride is an air and moisture-sensitive gray-green solid, which may be stored indefinitely under a dry nitrogen atmosphere. It is insoluble in common organic solvents. In addition to its use as a precursor for compounds 

Tetrakis(trifluoroacetato)ditungsten(II) is a bright yellow, diamagnetic solid that is highly air sensitive. It is very soluble in diethyl ether, THF, toluene, and dichloromethane and moderately soluble in hexane. The 84.26 MHz 19F NMR spectrum (in C6D6) consists of a single sharp resonance at 5 — 70.1 versus CFC13( 5 0.0). Other spectroscopic data and physicochemical properties are reported in the literature.17 

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Tungsten tetrachloride [13470-14-9], WCl, is obtained as a coarse, crystalline, deHquescent soHd that decomposes upon heating. It is diamagnetic and maybe prepared by the thermal-gradient reduction of WCl with aluminum (10). 

Although commercially available (Aldrich), polymeric tungsten tetrachloride is routinely prepared by McCarley s method,7,15 which is given below. Tungsten hexachloride and tungsten hexacarbonyl (Strem) are used without further purification. Sodium-mercury amalgam (0.5 wt%) is prepared in a 500-mL two-necked round-bottomed flask equipped with a N2 gas inlet and a stopper, by adding 6.83 g (297 mmol) of sodium metal in small pieces ( 0.1-0.2 cm3) to 100 mL of mercury. 

Cl40,Ru2C24Hj4, Ruthenium(II) x-aqua-bis-(p.-chloroacetato)bis[(chloroacetato)-T)4-cycloocta-1,5-diene)-, 26 256 C14W, Tungsten tetrachloride, 26 221 C15H8MoN20, Molybdate(V), pentachloro-oxo-... 

More recently the W2(C8H8)3 species was prepared from tungsten tetrachloride and potassium cyclooctatetraenide in THF (88). The crystal structure of this air-stable dimer has been interpreted in terms of a quadruple bond, albeit the tungsten-tungsten separation is a relatively lengthy 2.38 A as compared to the 2.26 A distance found in the W2Me8 xaJ ion noted above. Earlier reports of W2(C8II8)3 did not include structural or preparative details (32). 

Tungsten tetrachloride is a very useful starting material for preparing many lower-valent tungsten compounds. The best methods of preparation are ... 

Tungsten Tetrachloride, WGI4.—By partial reduction, with hydrogen, of the hexachloride. Riche obtained this compound in the form of voluminous, greyish-brown crystals, which may be more readily obtained by distilling a mixture of the hexa- and penta-ehlorides at a... 

The colloidal solution may also be prepared by dissoh-ing tungsten tetrachloride in alcohol and ether (equal volumes) and then diluting with alcohol and water. The solution obtained acts as a positive colloid and coagulates immediately when small quantities of neutral salts, hydroxides, or strong acids are added. On passing an electric current through the solution, a deep blue precipitate separates at the cathode. ... 

For large-scale preparations of the tetrachloride oxides, the reaction of the metal trioxide with sulfinyl chloride is most convenient. The procedure outlined below is similar to that of Col ten and co-workers,7 but gives details for obtaining the compounds, particularly tungsten tetrachloride oxide, in excess of 50-g quantities. The reactions may be scaled up or down several fold without deleterious effect. 

U02CI2 URANIUM DICHLORIDE DIOXIDE 1751 WCI4 TUNGSTEN TETRACHLORIDE 1793... 

U02F2 URANIUM DIFLUORIDE DIOXIDE 1752 WCI4[g] TUNGSTEN TETRACHLORIDE (GAS) 1793... 

VC0.88 VANADIUM 0.88-CARBIDE 1766 WOCI4 TUNGSTEN TETRACHLORIDE OXIDE 1811... 

V2C DIVANADIUM CARBIDE 1767 WOCI4[g] TUNGSTEN TETRACHLORIDE OXIDE (GAS) 1812... 

Cl4Nb02CgH,g, Niobium, tetrachlorobis-(tetrahydrofuran)-, 29 120 CI4OW, Tungsten tetrachloride oxide,... 

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