A Versatile and Unprecedented Triply Bonded Dimolybdenum Carbonyl Anion

Chemical reduction of [Mo 2 Cp 2 (μ-Cl)(μ-PA 2 )(CO) 2 ] (A = Cy, Ph, OEt) gives the corresponding alkaline metal salts of the triply bonded anions [Mo 2 Cp 2 (μ-PA 2 )(μ-CO) 2 ] -, which exhibit both molybdenum and oxygen nucleophilic sites. The PCy 2 anion reacts easily with NH 4 +, [AuCl(PR 3 )], or MeI to give unsaturated dicarbonyls [Mo 2 Cp 2 (μ-X)(μ-PA 2 )(CO) 2 ] (X = H, AuPR 3, Me), while [Me 3 O]BF 4 gives the methoxycarbyne [Mo 2 Cp 2 (μ-COMe)(μ-PCy 2 )(μ-CO)] and allyl chloride rearranges to give the unsaturated alkenyl complex [Mo 2 Cp 2 (μ-PCy 2 )(μ-CMeCH 2 )(CO) 2 ].