A. Bates et al., NUCLEOPHILIC ACTIVATION OF COORDINATED CARBON-MONOXIDE - REACTION OF TUNGSTEN HEXACARBONYL WITH METHOXIDE SALTS, Inorganic chemistry, 32(12), 1993, pp. 2651-2656
Kinetics studies of the reactions of [Na+] [OCH3-] and [((C6H5)3P)2N+]
[OCH3-] with W(CO)6 are reported. The preparation of acetonitrile sol
utions Of ((C6H5)3P)2NOCH3, a convenient source of solubilized methoxi
de ion in aprotic media, is described. Second-order rate constants (73
0 +/- 130 M-1 s-1 and 743 +/- 61 M-1 s-1) and equilibrium constants (3
200 +/- 300 M-1 and 1400 +/- 200 M-1) for the formation of the methoxy
carbonyl complexes [M+] [W(CO)5CO2CH3-] (M+ = Na+ and ((C6H5)3P)2N+, r
espectively) at 25-degrees-C are several orders of magnitude lower tha
n those reported for the formation of group VIII methoxycarbonyl compl
exes. Addition of trace quantities of water to THF/CH30H solutions of
[Na+] [W(CO)5CO2CH3-] suprisingly resulted in the formation Of W(CO)6
and not the expected metal hydride HW(CO)5-. These observations are co
nsistent with the previously reported variation in catalytic activity
of group VI and VIII metal carbonyl compounds for the water gas shift
reaction.