Unusual reactions of cationic carbyne complexes of manganese and rhenium with [NMe4][HFe(CO)4] to form heteronuclear dimetal carbene-bridged complexes

Abstract

The reaction of a cationic carbyne complex of manganese [Mn(CPh)(η-C₅H₅)(CO)₂]BBr₄ 1 with the salt [NMe₄][HFe(CO)₄] 3 in thf at low temperature gave [Mn(η-C₅H₅)(CO)₃] 4 and a novel dimetal carbene-bridged complex [MnFe{µ-C(H)Ph}(η-C₅H₅)(CO)₅] 5. The cationic rhenium carbyne complex [Re(CPh)(η-C₅H₅)(CO)₂]BBr₄ 2 similarly reacted with 3 to give [Re(η-C₅H₅)(CO)₃] 6 and [ReFe{µ-C(H)Ph}(η-C₅H₅)(CO)₆] 7. Complex 5 reacted with carbon monoxide gas leading to cleavage of the µ-C–Mn and Mn–Fe bonds to afford 4 and a novel benzene-co-ordinated acyltricarbonyliron complex [Fe(PhCHCO)(CO)₃] 8. The reaction of 7 with PPh₃ yielded [ReFe{µ-C(H)Ph}(η-C₅H₅)(CO)₅(PPh₃)] 9. The structures of complexes 5, 8 and 9 have been established by X-ray diffraction studies.