COMPARATIVE-STUDY OF THE REACTIONS OF DIAZOMETHANE WITH MU(3)-IMIDOYL AND MU(3)-BUTYNE TRINUCLEAR CLUSTERS

The reaction of the mu3-imidoyl clusters (mu-H)(mu3-eta2-CH3C=NCH2CH3)Ru3(CO)9 (1), (mu-H)(mu3-eta2-C=NCH2CH2CH2)Os3(CO)9(2), and (mu-H)(mu-3-eta2-CH3CH2C=NCH2CH2CH3)Os3(CO)9 (3) with CH2N2N2 at 25-degrees-C yield the structurally analogous clusters (mu-H)2(mu3-eta2-CH(CH3)C=NCH2CH3)Ru3(CO)9 (4), (mu-H)2(mu3-eta2-CHC=NCH2CH2CH2)Os3(CO)9 (5), and (mu-H)2(mu3-eta2-CH(CH3CH2)C=NCH2CH2CH3)Os3(CO)9 (6), in which a methylene fragment has inserted into the carbon-metal sigma bond of the imidoyl ligand and undergone a C-H oxidative addition. The reaction of 1 with CD2N2 yields 4 with no hydrogen incorporation into the methyne hydrogen position. The reaction of 2-methylpyrrolidine with Os3(CO)10(CH3CN)2 gives (mu-H)(mu-eta2-C=NCH(CH3)CH2CH2)Os3(CO)10 (7) and (mu-H)(mu-eta2-CH2C=NCH2CH2CH2)Os3(CO)10 (8) as the two major products. On thermolysis 8 converts quantitatively to 5 suggesting that a nonacarbonyl analog of 8 may be an intermediate in the reaction of 2 with CH2N2. The reaction of the related alkyne complex (mu-CO)(mu3-eta2-CH3C2CH3)Os3(CO)9 (9) with CH2N2 at 25-degrees-C yields the methylene complex (mu-CH2)(mu3-eta2-CH3C2CH3)Os3(CO)9 (10, 59%) and (mu3-eta1-CH2N2)(mu3-eta2-CH3C2CH3)Os3(CO)9 (11, 22%). Compound 11 is a 50e- cluster with two metal-metal bonds and one nitrogen atom capping the cluster. Compound 10 undergoes carbon-carbon coupling and C-H oxidative addition only at elevated temperatures (128-degrees-C) to yield (mu-H)(mu3-eta3-CH3CC(CH3)Os3(CO)9 (12). Compound 11 converts to 10 photochemically. This sequence of reactions was previously reported but as starting from the coordinatively unsaturated alkyne cluster (mu3-eta2-C6H5C2C6H5)Os3(CO)9. Solid-state structures for 4, 5, 10, and 11 are reported. Compound 4 crystallizes in the monoclinic space group C2/c with a = 16.997 (3) angstrom, b = 8.941 (1) angstrom, c = 27.322 (6) angstrom, beta = 97.62 (1)-degrees, V = 4115 (2) angstrom3, and Z = 8. Least-squares refinement of 2851 observed reflections gave a final agreement factor of R = 0.026 (R(W) = 0.035). Compound 5 crystallizes in the triclinic space group P1BAR with a = 13.394 (8) angstrom, b = 15.601 (8) angstrom, c = 9.069 (7) angstrom, alpha = 88.51 (5)-degrees, gamma = 80.61 (6)-degrees, gamma = 86.96 (5)-degrees, V = 1867 (3) angstrom3 at -158-degrees-C, and z = 4. Least-squares refinement of 6576 observed reflections gave a final agreement factor of R = 0.070 (R(W) = 0.090). Compound 10 crystallizes in the triclinic space group P1BAR with a 12.117 (2) angstrom, b = 16.793 (3) angstrom, c = 9.229 (2) angstrom, alpha = 95.42 (2)-degrees, beta = 92.77 (2)-degrees, gamma = 92.79 (1)-degrees, V = 1865 (1) angstrom3, and Z = 4. Least-squares refinement of 5807 observed reflections gave a final agreement of R = 0.067 (R(W) = 0.079). Compound 11 crystallizes in the monoclinic space group P2(1)/c with a = 9.246 (2) angstrom, b = 13.813 (3) angstrom, c = 16.202 (3) angstrom, beta = 110.18 (2)-degrees, V = 1942 (1) angstrom3, and Z = 4. Least-squares refinement of 3478 observed reflections gave a final agreement factor of R = 0.040 (R(W) = 0.047).