Tungsten carbonyl reaction

Tungsten complexes, 3, 973-1015 alkoxy carbonyl reactions, 2, 355 alkyl alkoxy reactions, 2, 358 amides... 

Tungsten carbonyl is also used as a metal source at 350 00°C but carbon tends to remain incorporated in the stmcture.P l The reaction is as follows ... 

This reaction proceeds at a much faster rate than the hydrogen reduction of WFg. The result is erosion of the silicon substrate causing encroachment and tunnel defects. The use of a different precursor, such as tungsten carbonyl, W(CO)g, may solve this problem. CVD tungsten is presently limited mostly to multilevel-via-fill applications. 

Molybdenum and tungsten carbonyl hydride complexes were shown (Eqs. (16), (17), (22), (23), (24) see Schemes 7.5 and 7.7) to function as hydride donors in the presence of acids. Tungsten dihydrides are capable of carrying out stoichiometric ionic hydrogenation of aldehydes and ketones (Eq. (28)). These stoichiometric reactions provided evidence that the proton and hydride transfer steps necessary for a catalytic cycle were viable, but closing of the cycle requires that the metal hydride bonds be regenerated from reaction with H2. 

The tungsten carbonyl, Wx(CO) was synthesized and studied as a catalyst for ORR reactions.198-200 Through these studies, it was found that the tungsten carbonyl was active for ORR. The Koutecky-Levich plots showed that the electrons transferred approached four during ORR.199 It was also found that the tungsten carbonyl was active for the electrolysis of water.199... 

Sulfoxide adducts of chromium, molybdenum, and tungsten carbonyls have been studied as catalysts for the polymerization of monomers such as vinyl chloride (248). Simple adducts of the type [M(CO)5(Me2SO)] may be prepared by carbonyl displacement from the corresponding hexacarbonyl. Photochemical reactions are frequently necessary to cause carbonyl displacement in this manner, many carbonyl complexes of higher sulfoxides have been prepared (255, 256). Infrared (257) and mass spectral studies (154) of these complexes have appeared, and infrared data suggest that S-bonding may occur in Cr(0) sulfoxide complexes, although definitive studies have not been reported. 

There are two general procedures for the preparation of monomeric W11 complexes.269 In one, substituted tungsten carbonyls are oxidized by halogens under controlled conditions as exemplified by equations (18) and (19). In the second, W(CO)6 is first oxidized by Cl2 or Br2 at low temperature, followed by reaction of the oxidized product with the appropriate ligands. This preparative procedure is exemplified by equation (20). 

Alkyne-vinylcyclopropanes, metal-catalyzed [5+23-cycloadditions, 10, 605 Alkynides, with tungsten carbonyls, 5, 666 Alkynoic acids, stannylmetallation, 9, 374 Alkynoles, hydration-dehydration reactions, 6, 841... 

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