Chemistry of highly electrophilic binuclear cations.: 2.: Oxidation reactions of [W2(η5-C5H5)2(CO)4(μ-Ph2PCH2PPh2)] with [FeCp2][B{3,5-C6H3(CF3)2}4]

Chemical oxidation of the title compound [W2Cp2(CO)(4)(mu-dppm)] (Cp = eta(5)-C5H5; dppm = Ph2PCH2PPh2) with 1 equiv of [FeCp2](BAr4') (Ar' = 3,5-C6H3(CF3)(2)) leads to the tetracarbonyl radical [W2Cp2(CO)(4)(mu-dppm)](BAr4'), which experiences spontaneous decarbonylation to give the 31-electron radical [W2Cp2(mu-CO)(CO)(2)(mu-dppm)](BAr4'). Oxidation of [W2Cp2(CO)(4)(mu-dppm)] with 2 equiv of [FeCp2](BAr4') gives the tricarbonyl derivative [W2Cp2(mu-CO)(CO)(2)(mu-dppm)](BAr4')(2). The same result is obtained when oxidizing the radical [W2Cp2(mu-CO)(CO)(2)(mu-dppm)]-(BAr4') with [FeCp2](BAr4'). The triply bonded complex [W2Cp2(mu-CO)(CO)(2)(mu-dppm)](BAr4')(2), which displays fluxional behavior in solution, reacts with P(OMe)(3) to give [W2Cp2(mu-CO)(CO){P(OMe)(3)}(mu-dppm)](BAr4')(2), the structure of which has been solved through a single-crystal X-ray diffraction study. Reaction of [W2Cp2(mu-CO)(CO)(2)(mu-dppm)](BAr4')(2) with salts of halide ions X- (X = Cl, Br, I) gives the corresponding halo derivatives [W2Cp2(mu-X)(mu-CO)(CO)(2)(mu-dppm)] (BAr4'). When X = I, a mixture of two isomers differing in the relative positions of the bridging halide and carbonyl is obtained. The same halide compounds were obtained in the reactions of paramagnetic [W2Cp2(mu-CO)(CO2(mu-dppm)]-(BAr4') with halogens X-2. The tricarbonyl radical was found to react slowly with water to give the known hydroxycarbyne derivative [W2Cp2(mu-COH)(CO2(mu-dppm)](BAr4').