A versatile and unprecedented triply bonded dimolybdenum carbonyl anion

Chemical reduction of [Mo2Cp2(mu-Cl)(mu-PA(2))(CO)(2)] (A = Cy, Ph, OEt) gives the corresponding alkaline metal salts of the triply bonded anions [Mo2Cp2(mu-PA(2))(mu-CO)(2)](-), which exhibit both molybdenum and oxygen nucleophilic sites. The PCy2 anion reacts easily with NH4+, [AuCl(PR3)], or MeI to give unsaturated dicarbonyls [Mo2Cp2(mu-X)(mu-PA(2))(CO)(2)] (X = H, AuPR3, Me), while [Me3O]BF4 gives the methoxycarbyne [Mo2Cp2(mu-COMe)(mu-PCy2)(mu-CO)] and allyl chloride rearranges to give the unsaturated alkenyl complex [Mo2Cp2(mu-PCy2)(mu-CMeCH2)(CO)(2)].