Formation of thioruthenium carbonyl clusters via a thioallyl cation complex

Article abstract of DOI:10.1021/om00038a018

Tetramethylallene episulfide (1a) reacts with Ru₃(CO)₁₂ to afford the oxidative addition hydride clusters Ru₃(CO)₁₀[μ-S(C=CMe₂)C(Me)=CH ₂](μ-H) (2) and Ru₃(CO)₉[μ-S(C=CMe₂)C(Me)=CH ₂](μ-H) (3), respectively. The structure of 2 was characterized crystallographically. The cluster 2 undergoes decarbonylation at 60°C to form 3 in 47% yield. The cluster 3 can regenerate 2 by bubbling with carbon monoxide under 1 atm of pressure at room temperature, in 80% yield. The chemical correlations leave little doubt about the structure of 3 which has a six-electron donating (μ-S)(μ-H)η²-dimethylpentadiene ligand. The reaction of 1-tert-butyl-3,3-diphenylallene 1-episulfide (1b) with Ru₃(CO)₁₂ resulted in the formation of the cluster Ru₃(CO)₁₀[2-(μ-S)-1-tert-butyl-3-phenylindene](μ-H) (5). The X-ray structure of 5 shows that intramolecular cyclization has occurred besides C-S bond cleavage. The thioallyl cation complexes 9 and 10 are the intermediates of the formation of clusters 2 and 5. Upon warming to 80-120°C, 2 and 5 were finally converted to desulfurized products 2,4-dimethyl-1,3-pentadiene (6) (quantitative) and 1-tert-butyl-3-phenylindene (7) (56%) along with thio cluster HRu₅(CO) ₁₅[2-(μ-S)-1-tert-butyl-3-phenylindene](μ₄-S) (8) (30%).