REACTIONS OF DINUCLEAR AND POLYNUCLEAR COMPLEXES .7. REACTION OF [(CO)3CO(MU-RC2R')CO(CO)3] (R = R' = CF3, CO2ME - R = CF3, C6H5 AND R' = H) WITH [(FECP(CO)2)2] - SYNTHESIS, CHARACTERIZATION, AND REACTIVITY OF DINUCLEAR AND TETRANUCLEAR MIXED-METAL COMPLEXES - ALKYNE COORDINATION AND SCISSION BY A TETRAMETALLIC FRAMEWORK - CRYSTAL-STRUCTURES OF [CO3FECP(MU-4-ETA-2-C = CHCF3)(ETA-6-C7H8)(MU-CO)2(CO)4] AND [CO3FECP2(MU-4-ETA-2-C=CCF3)(MU-CO)(CO)5]

The dinuclear complexes [(CO)3 activated Co(mu-R-C = C-R')Co(CO)3] (R = R' = CF3, CO2 Me) react with [{CpFe(CO)2}2] in refluxing octane to afford tetranuclear mixed-metal complexes [Co2Fe2Cp2(CO)4(mu-3-CO)2(mu-4-RC2R')] (R = R' = CF3, 1; R = R' = CO2Me, 6), [CoFe3Cp3(CO)2(mu-3-CO)2(mu-4-RC2R')] (R = R' = CF3, 2) in good yields, together with the di- and tetranuclear species [(CO)3 activated Co(mu-C4R4)FeCp] (R = R' = CO2Me, 7), [Co4(CO)10(mu-4-RC2R')] (R = R' = CO2Me, 5), and [Co4Cp2(CO)6(mu-4-RC2R')] (R = R' = CF3, 4). Reactions between [(CO)3 activated Co(mu-H-C=C-R)Co(CO)3] (R = CF3, Ph) and [{CpFe(CO)2}2] in refluxing octane give the tetrametallic cluster compounds [Co3FeCp(CO)7(mu-CO)2(mu-4-C2HR)] (R = CF3, 9; R = Ph, 12) in good yields, together with small amounts of tetra- and dinuclear derivatives [Co3FeCp2(CO)7(mu-C2R)] (R = CF3, 8; R = Ph, 13), [Co2Fe2Cp2(CO)4(mu-3-CO)2(mu-4-HC2R)] (R = CF3, 10), and [Co2(CO)6(mu-RC2CH=CHR)] (R = Ph, 11). Heating 9, in refluxing toluene yields the toluene-substituted cluster [Co3FeCp(CO)4(mu-CO)2(C6H5Me){mu-4-C2H(CF3)}] (17). The molecular structures of compound 17 and 8 have been established by single-crystal X-ray diffraction studies. 17 crystallizes in the monoclinic space group P2(1)/n with a = 8.569 (2), b = 26.650 (6), c = 9.380 (10) angstrom, beta = 90.41 (7)-degrees; R = 0.040 for 1781 observed reflections. Cluster 17 is characterized by a ''butterfly'' arrangement of the FeCo3 core. All four metal atoms interact with a mu-4-vinylidene ligand. 8 crystallizes in the triclinic space groups P1BAR with a = 8.379 (1), b = 9.594 (2), c = 14.913 (2) angstrom, alpha = 89.06 (2), beta = 75.18 (1), gamma = 70.75 (2)-degrees; R = 0.034 for 2240 observed reflections. The tetranuclear complex 8 has an Fe-spiked-Co3-triangular metal atom frame. Thermolyses of 1 and 6 in refluxing toluene in presence of Me3NO provide in good yield the dialkylidyne clusters [Co2Fe2Cp2(CO)5(mu-3-CR)2] (R = CF3 3; R = CO2Me, 14) which result from C = C bond cleavage. The molecular structure of 3 has been previously established by a single-crystal X-ray diffraction study. Treatments of the dialkylidyne cluster 3 with phosphite and nitrosyl hexafluorophosphate give, respectively, the monosubstituted complex [Co2Fe2Cp(CO)4{P(OMe)3}(mu-C-CF3)2] (15) and the nitrosyl derivative [Co2Fe2Cp2(mu-CO)2(NO)2(mu-C-CF3)2] (16). Carbonylation of the mu-4-vinylidene product 9 affords the mu-carbyne complex [Co3(CO)9(mu-3-CCH2CF3)] (18). The mass, infrared, and H-1, F-19, and C-13{H-1} NMR spectra of the new compounds are reported and discussed.