Molybdenum and Tungsten Carbonyls

Feldmann J, WR Cullen (1997) Occurrence of volatile transition metal compounds in landfill has synthesis of molybdenum and tungsten carbonyls in the environment. Environ Sci Technol 31 2125-2129. 

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. 

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. 

CjHjS, Thiophene, tetrahydro-gold complexes, 26 85-87 C4H,NO, 2-Propenamide, 2-methyl-nickel complex, 26 205 C4H1()02, Ethane, 1,2-dimethoxy-solvates of chromium, molybdenum, and tungsten carbonyl cyclopentadienyl complexes, 6 343 tungsten complex, 26 50 ytterbium complex, 26 22 C4H i02.NaC5H5, Ethane, 1,2-dimethoxy-compd. with cyclopentadienylsodium, 26 341... 

It is also noteworthy that both molybdenum and tungsten carbonyls react with carboxylic acids to give excellent yields of another type of trinuclear cluster with equilateral triangles of metal atoms, in which the triangles are capped above and below by single oxygen atoms (52). 

Molybdenum and tungsten carbonyl nitrosyls undergo oxidative addition with SnCl4 and SnBr4 in CHjClj in yields close to 100%, e.g. ... 

Since 1939 I have come into closer contact with the organometallic chemistry of transition metals than I did during my first attempts to arylate Fe(CN)g , My attention was attracted to the paper by Job and Cassal, who synthesized chromium, molybdenum, and tungsten carbonyls by a simultaneous reaction of the halides with carbon monoxide and Grignard compounds. 

Benzenetellurolates reacted with molybdenum and tungsten carbonyl complexes. 

C4H 0., Ethane, 1,2-dimethoxy-, ytterbium complex, 26 22 solvates of chromium, molybdenum, and tungsten carbonyl cyclopentadienyl complexes, 26 343 tungsten complex, 26 50... 

Typical trends have been observed in two-bond C-P couplings measured by Sanchez et for two series of the new molybdenum and tungsten carbonyl complexes [M(CO)4(o-Ph2PC6H4-CH=NR)] (M = Mo, W R = Aik), the trans couplings ca. 35 Hz) being significantly larger than the cis ones (3-9 Hz). 

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