Three products were isolated from the thermolysis of either Os3(CO)11[SCH2CMe2CH2] (1) or Os3-(CO)10[mu-SCH2CMe2CH2] (2) at 97-degrees-C. These were identified on the basis of IR and H-1 NMR spectroscopy and single-crystal X-ray diffraction analyses as Os2(CO)6[mu-SCH2C(Me)CH2(CH2)](mu-H) (3; 14%,18%), Os3(CO)9[mu-SCH2C(Me)2CH](mu-H) (4; 18%, 21%) and Os4(CO)12(mu-CO)[mu-SCH2CMe2CH2] (5; 8%, 12%). Treatment of 4 with H2/CO (1200 psi, 5/1) at 97-degrees-C yielded 3 (47%) and Os3(CO)10[mu-SCH2CMe3](mu-H) (23%). When subjected to UV irradiation, 1 and 2 were converted to the metallacyclic isomer Os3( CO)10[mu-SCH2CMe2CH2] (6) in 30% and 47% yields, respectively. Thermolysis of 6 at 97-degrees-C produced 3 and 4. Compound 6 was carbonylated (500 psi) at 70-degrees-C to yield Os3(CO)11[mu-SCH2C(Me)2CH2] (7; 11%) and Os3(CO)11[mu-SCH2C(Me)2CH2C=O] (8; 42%), which is formed by a CO insertion into the metal-carbon bond of the metallacycle. Compound 6 reacts with [(Et)4N]+Cl- at 25-degrees-C to form [Os3(CO)9(mu-SCH2C-(Me)2CH2) (mu-Cl)]-[(Et)4N]+ (9; 87%) by decarbonylation and addition of Cl- to the cluster. Complexes 7-9 were also characterized by single-crystal X-ray diffraction analyses. All three compounds contain open clusters of the three metal atoms in which the sulfur atom bridges the pair of metal atoms that are not mutually bonded. Compound 8 contains a thiametallacyclohexanone ring formed by the insertion of a CO group into the metal-carbon bond of the metallacycle in 7. Compound 9 was formed by the cluster-opening addition of chloride to 6 and contains a bridging chloro ligand. Data for 3: space group = P2(1)/m, a = 6.3804 (8) angstrom, b = 14.149 (2) angstrom, c = 8.649 (1) angstrom, beta = 96.70 (1)-degrees, Z = 2, 1019 reflections, R = 0.036. Data for 4: space group = P1BAR, a = 9.330 (2) angstrom, b = 14.352 (2) angstrom, c = 8.656 (2) angstrom, alpha = 93.73 (2)-degrees, beta = 117.58 (1)-degrees, gamma = 101.09 (2)-degrees, Z = 2, 1977 reflections, R = 0.023. Data for 7: space group = Pn, a = 9.791 (2) angstrom, b = 10.5812 (9) angstrom, c = 10.957 (1) angstrom, beta = 102.09 (1)-degrees, Z = 2,1693 reflections, R = 0.038. Data for 8: space group P1BAR, a = 14.108 (4) angstrom, b = 16.628 (7) angstrom, c = 9.985 (4) angstrom, alpha = 90.09 (4)-degrees, beta = 93.24 (3)-degrees, gamma = 81.97 (3)-degrees, Z = 4,3838 reflections, R = 0.048. Data for 9: space group = P2(1)/n, a = 9.320 (2) angstrom, b = 18.484 (5) angstrom, c = 17.943 (3) angstrom, beta = 95.04 (2)-degrees, Z = 4, 2886 reflections, R = 0.024.
