UNUSUAL REACTIONS OF CATIONIC CARBYNE COMPLEXES OF MANGANESE AND RHENIUM WITH [NME4][HFE(CO)(4)] TO FORM HETERONUCLEAR DIMETAL CARBENE-BRIDGED COMPLEXES

The reaction of a cationic carbyne complex of manganese [Mn(=CPh)(eta- C5H5)(CO)(2)]BBr4 1 with the salt [NMe4][HFe(CO)(4)] 3 in thf at low t emperature gave [Mn(eta-C5H5)(CO)(3)] 4 and a novel dimetal carbene-br idged complex [MnFe{mu-C(H)Ph}(eta-C5H5)(CO)(5)] 5. The cationic rheni um carbyne complex [Re(=CPh)(eta-C5H5)-(CO)(2)]BBr4 2 similarly reacte d with 3 to give [Re(eta-C5H5)(CO)(3)] 6 and [ReFe{mu-C(H)Ph}(eta-C5H5 )(CO)(6)] 7. Complex 5 reacted with carbon monoxide gas leading to cle avage of the mu-C-Mn and Mn-Fe bonds to afford 4 and a novel benzene-c o-ordinated acyltricarbonyliron complex [Fe(PhCHCO)(CO)(3)] 8. The rea ction of 7 with PPh3 yielded [ReFe{mu-C(H)Ph}(eta-C5H5)(CO)(5)(PPh3)] 9. The structures of complexes 5, 8 and 9 have been established by X-r ay diffraction studies.