Chemistry of Highly Electrophilic Binuclear Cations. 4. Synthesis and Reactivity of the Dinuclear Radicals [M2(η5-C5H5)2(μ-CO)2(CO)2(μ-L2)][B{3,5-C6H3(CF3)2}4] (M = Mo, W; L2= Ph2PCH2PPh2, Me2PCH2PMe2, (EtO)2POP(OEt)2)

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Oxidation of the compounds [M2Cp2(CO)4(μ-L2)] (M = Mo, W; Cp = η5-C5H5; L2 = Ph2PCH2PPh2 (dppm), Me2PCH2PMe2 (dmpm), (EtO)2POP(OEt)2 (tedip)) with [FeCp2](BAr‘4) (Ar‘ = 3,5-C6H3(CF3)2) gives the corresponding tetracarbonyl radicals [M2Cp2(μ-CO)2(CO)2(μ-L2)](BAr‘4). The stability of these paramagnetic complexes depends on the ligand and the metal. Thus, the dmpm complexes are stable in solution for reasonable periods of time, whereas the dppm complexes experience spontaneous decarbonylation at room temperature to give the radicals [Mo2Cp2(μ-CO)2(μ-dppm)](BAr‘4) and [W2Cp2(μ-CO)(CO)2(μ-dppm)](BAr‘4). The tedip-bridged derivatives are the most unstable radicals, with the ditungsten cation experiencing rapid hydrogen atom capture to give the hydride complex [W2Cp2(μ-H)(CO)4(μ-tedip)](BAr‘4). The complexes [M2Cp2(μ-CO)2(CO)2(μ-L2)](BAr‘4) react with NO to give the binuclear nitrosyl derivatives [M2Cp2(CO)4(NO)(μ-L2)](BAr‘4) (M = Mo, W; L2 = dmpm, tedip) and [Mo2Cp2(μ-CO)(CO)2(NO)(μ-dmpm)](BAr‘4). Some mononucl...