REACTIONS OF MOLYBDENUM AND TUNGSTEN PROPARGYL COMPOUNDS WITH IRON AND RUTHENIUM CARBONYLS - SYNTHESIS AND REACTIVITY OF HETERONUCLEAR METAL MU-ALLENYL COMPLEXES

Reactions of transition-metal-propargyl complexes L(n)MCH2C = CR (L(n)M = (CO)3CpMo, R = Me (1a), Ph (1b); L(n)M = (CO)3CpW, R = Me (1c), Ph (1d), p-MeC6H4 (1e); L(n)M = (CO)3Cp'W (Cp' = eta-5-C5H4Me), R = Ph (1f), p-MeC6H4 (1g); L(n)M = (CO)3IndW (Ind = eta-5-C9H7), R = Ph (1h)) with Fe2(CO)9 or M'3(CO)12 provide the new heteronuclear metal mu-allenyls (CO)3Fe(mu-eta-2,eta-3-RC = C = CH2)MCp(or Ind)(CO)2 (2) and (CO)6M'2(mu-3-eta-1,eta-2,eta-2-RC = C = CH2)MCp(CO)2 (M' = Fe (3), Ru (4)). These new products were characterized by a combination of elemental analysis, mass spectrometry, and IR and H-1 and C-13 NMR spectroscopy; the structures of 2e, 3d, and 4 were determined by single-crystal X-ray analysis. Crystallographic parameters are as follows: 2e P2(1)/n, a = 17.259 (5) angstrom, b = 8.184 (3) angstrom, c = 26.920 (7) angstrom, beta = 90.65 (2)degrees, Z = 8, R = 0.030, R(w) = 0.038 for 6533 independent reflections with I > 3-sigma(I); 3d P2(1)/c, a = 12.185 (5) angstrom, b = 12.754 (7) angstrom, c = 15.418 (9) angstrom, beta = 111.87 (4)degrees, Z = 4, R = 0.029, R(w) = 0.041 for 4896 independent reflections with I > 3-sigma(I); 4 P2(1)/n, a = 9.936 (7) angstrom, b = 18.98 (2) angstrom, c = 11.752 (8) angstrom, beta = 93.12 (6)degrees, Z = 4, R = 0.053, R(w) = 0.061 for 2669 independent reflections with I > 3-sigma(I). Compounds 2 represent rare examples of binuclear metal mu-eta-2,eta-3-allenyls, with 2e featuring a remarkably sharp angle about the central allenyl carbon (128.9 (6)degrees). Compounds 3 and 4 are the first reported examples of heterotrinuclear metal-mu-3-eta-1,eta-2,eta-2-allenyl clusters. Reactivity of 2-4 toward metal framework expansion, addition of unsaturated compounds, protonation, substitution of CO, and oxidation with I2 is presented.