137333-00-7Relevant academic research and scientific papers
Carbon-sulfur bond cleavage with a loss of stereochemistry in the ring opening of trans-2,4-diphenylthietane by Os3(CO)10(NCMe)2
Adams, Richard D.,Pompeo, Michael P.
, p. 103 - 111 (2008/10/08)
The reaction of Os3(CO)10(NCMe)2 with trans-2,4-diphenylthietane (2,4-DPT) at 25 °C resulted in the formation of two isomers, cis- and trans-Os3(CO)10[μ-SC(H)PhCH2C(H)Ph] (1), in a combined yield of 76%. The cis product was characterized by single-crystal X-ray diffraction analysis and was found to contain a thiametalladiphenylcyclopentane ring formed by the opening of the thietane ring. The cis and trans isomers differ in the orientation of their phenyl substituents. The isomers are formed in approximately equal amounts in the early stages of the reaction, but the trans isomer subsequently slowly isomerizes to the cis isomer. The observed loss in stereochemistry at the carbon center is attributed to a stepwise ring-opening mechanism. When compound 1 was heated to 97 °C under a CO atmosphere, five compounds were formed: Os3(CO)10[μ-SC(H)PhC(H)=C(H)Ph[(μ-H) (2) (22%), Os2(CO)7[μ-SC(H)(C6H4)CH 2CH2Ph] (3) (11%), Os3(CO)11[μ-SC(H)PhCH2C(H)Ph] (4) (39%), H2Os6(CO)17(μ3-S)(μ 4-S) (5) (a trace amount), and Os3(CO)12. Compounds 3 and 5 and the known compound Os3(CO)9(μ3-CO)(μ3-S) (6) were obtained in better yields by heating 2 to 125 °C in octane solvent. Compounds 2-4 were characterized by IR, 1H NMR, and single-crystal X-ray diffraction analyses. Compound 2 is an isomer of 1 and contains a diphenylpropenethiolate and hydride ligand formed by a β-eliminationβ transformation of the ring system in 1. The mechanism of this transformation was not established. Compound 3 contains only two metal atoms and an ortho-metalated phenyl ring. Compound 4 is a CO adduct of 1 formed by the cleavage of the sulfur-bridged metal-metal bond. Crystallographic data are as follows. cis-1: space group P21/c, a = 8.674 (2) A?, b = 35.09 (1) A?, c = 9.449 (2) A?, β = 106.41 (1)°, Z = 4, 2053 reflections, R = 0.033. 2: space group C2/c, a = 13.845 (2) A?, b = 14.545 (4) A? c = 28.907 (6) A?, β = 98.88 (1)°, Z = 8, 2519 reflections, R = 0.027. 3: space group P21/c, a = 8.337 (1) A?, b = 17.311 (4) A?, c = 16.409 (3) A?, β = 100.82 (1)°, Z = 4, 2299 reflections, R = 0.036. 4: space group P1, a = 14.319 (2) A?, b = 17.794 (5) A?, c = 12.257 (4) A?, α = 106.69 (2)°, β = 90.74 (2)°, γ = 82.56 (2)°, Z = 4, 4020 reflections, R = 0.041.
Cleavage of carbon-sulfur bonds in thiolato ligands in osmium carbonyl cluster compounds. The synthesis and structural characterization of H2Os6(CO)18(μ4-S)(μ 3-S) and two isomers of H2Os6(CO)17(μ4-S)(μ 3-S)
Adams, Richard D.,Horváth, István T.,Mathur, Pradeep,Segmüller, Brigitte E.
, p. 996 - 1005 (2008/10/08)
Thermal degradation of HOs3(CO)10(μ-SCH2C6H 5), I, at 150°C leads to cleavage of the carbon-sulfur bond in the phenylmethanethiolato ligand by two competing processes. By one process the cleavage is followed by the elimination of toluene and the formation of the sulfidoosmium carbonyl clusters Os3-(CO)9(μ3-S)2, Os6(CO)16(μ4-S)(μ3-S), and Os7(CO)20(μ4-S)2. The second mechanism involves homolysis of the carbon-sulfur bond and formation of dibenzyl, the red hydride-containing hexanuclear cluster H2Os6(CO)17(μ4-S)(μ 3-S), III, and its green isomer IV. Both III and IV were characterized by X-ray crystallographic methods. For III: space group C2/c, a = 20.364 (5) A?, b = 9.764 (4) A?, c = 32.544 (7) A?, β = 114.01 (2)°, V = 5900 (6) A?3, Z = 8, ρcalcd = 3.79 g/cm3. The structure was solved by direct methods (MULTAN) and refined (2456 reflections, F2 ≥ 3.0σ(F2)) to the final values of the residuals RF = 0.037 and RwF = 0.034 III contains two triosmium groupings linked by a quadruply bridging sulfido ligand and two metal-metal bonds. The quadruply bridging sulfido ligand has a highly distorted tetrahedral geometry with Os-S-Os bond angles ranging from 72.5 (1)° to 149.4 (2)°. III also contains a triply bridging sulfido ligand two bridging hydride ligands, and 17 linear terminal carbonyl ligands. For IV: space group P21/n, a = 11.124 (3) A?, b = 14.090 (5) A?, c = 18.694 (7) A?, b = 92.00 (3)°, V = 2928 (3) A?3, Z = 4, ρcalcd = 3.82 g/cm3. The structure was solved by direct methods (MULTAN) and refined (2515 reflections, F2 ≥ 3.0σ(F2)) to final values of the residuals RF = 0.054 and RwF = 0.058. The structure of IV consists of a rhombus of four osmium atoms bridged on opposite sides by quadruply bridging and triply bridging sulfido ligands. Two adjacent edges of the rhombus contain bridging Os(CO)4 groups. The other two edges contain bridging hydride ligands. When exposed to UV radiation at room temperature, I undergoes facile homolysis of the carbon-sulfur bond and yields dibenzyl, compound III and the new cluster H2Os6(CO)18(μ4-S)(μ 3-S), V. For V: space group P1, a = 9.022 (2) A?, b = 11.986 (4) A?, c = 14.370 (3) A?, α = 89.94 (2)° β = 78.23 (2)°, γ = 83.39 (3)°, V = 1511 (1) A?3, Z = 2, ρcalcd = 3.76 g/cm3. The structure was solved by the heavy-atom method and refined (3407 reflections, F2 ≥ 3.0σ(F2)) to final values of the residuals RF = 0.044 and RwF = 0.044. Compound V is structurally similar to III. It contains two groups of three osmium atoms which are linked by a quadruply bridging sulfido ligand and one metal-metal bond which also contains a symmetrical bridging carbonyl ligand. The quadruply bridging sulfido ligand contains a highly distorted tetahedral geometry, Os-S-Os angles range from 74.7 (1)° to 144.5 (2)°. In addition, there is a triply bridging sulfido ligand, two bridging hydride ligands, and 17 linear terminal carbonyl ligands. V can be converted into III both by thermolytic (68°C) and photolytic decarbonylation.
