REACTION OF THE METAL-SUBSTITUTED VINYLIDENE COMPLEX CP'(CO)2MN[=C=(H)-FP-ASTERISK] WITH EXCESS BULI, GIVING ACYLATED DINUCLEAR BRIDGING ALKENYL COMPLEXES, CP'MNCP-ASTERISK-FE[MU-CH=C(E)-C(=O)-BU] (MU-CO)(CO)2 (E=H, ME) - CONFIRMATION OF THE INTRAMOLECULAR 1,2-H SHIFT MECHANISM PROPOSED FOR THE FLUXIONAL PROCESS OF THE CATIONIC DIIRON MU-ETHYNYL COMPLEXES [((ETA(5)-C5R5)FE(CO)2)2(MU-C-EQUIVALENT-TO-C-H)]BF4

Reaction of the heterobimetallic bridging vinylidene complex CpMn(CO)2[=C=C(H)Fp*] (2) with an excess amount of n--BuLi followed by quenching with electrophiles produces the dinuclear bridging mu-eta1-(Fe):eta2(Mn)-3-oxo-hept-1-en-1-yl complexes Cp'MnCp*Fe[mu-CH=C(E)-C(=O)-Bu](mu-CO)(CO)2 [E = H (6a), Me (6b)] via nucleophilic addition to the anionic ethynediyl intermediate [Cp'(CO)2Mn-C=C-Fe(CO)2Cp*]- (7) resulting from deprotonation of 2. It has been proved that the previously reported reaction of the cationic diiron mu-ethynyl complex [Fp2*(mu-C=C-H)]BF4 (3) (isoelectronic with 2) follows a similar reaction pathway. Crystal data for 6b: monoclinic, space group C2/c, a = 33.862(5) angstrom, b = 9.140(4) angstrom, c = 16.815(5) angstrom, beta = 98.72(2)-degrees, V = 5144(5) angstrom3, Z = 8.