Synthesis, Characterization, and Dynamic Behaviour of Triosmium Clusters Containing the Tridentate Ligand {Ph 2 PCH 2 CH 2 } 2 S (PSP)

Reaction of [Os 3 (CO) 11 (NCMe)] with bis‐diphenylphosphanylethylene sulfide, {Ph 2 PCH 2 CH 2 } 2 S (PSP), leads to the formation of [Os 3 (CO) 11 (PSP)] and [{Os 3 (CO) 11 } 2 (μ‐PSP)] in good yield. Similarly, treatment of [Os 3 (CO) 10 (NCMe) 2 ] with PSP affords the cluster [Os 3 (CO) 10 (μ‐PSP)], in which the two phosphanes of the PSP ligand coordinate to different osmium atoms of the same triosmium unit. Reaction of [Os 3 (CO) 11 (PSP)] with [Os 3 (CO) 10 (NCMe) 2 ] yields the compound 1,2‐[{Os 3 (CO) 11 }(μ 3 ‐PSP){Os 3 (CO) 10 }] in which the thioether moiety and one of the phosphane groups of the PSP ligand are coordinated equatorially to the {Os 3 (CO) 10 } subunit. The cluster 1,2‐[{Os 3 (CO) 11 }(μ 3 ‐PSP){Os 3 (CO) 10 }] is also formed when [Os 3 (CO) 11 (PSP)] is oxidatively decarbonylated by reaction with trimethylamine N ‐oxide. The metastable cluster 1,2‐[{Os 3 (CO) 11 }(μ 3 ‐PSP){Os 3 (CO) 10 }] undergoes slow isomerisation at room temperature to form 1,1‐[{Os 3 (CO) 11 }(μ 3 ‐PSP){Os 3 (CO) 10 }] in which the thioether and phosphane moieties coordinate in a chelating mode to one of the {Os 3 (CO) 10 } subunits with the thioether moiety in an axial position. The dynamic behaviour of these clusters has been investigated by variable‐temperature 13 C{ 1 H} and 13 P{ 1 H} NMR spectroscopy. The solid‐state structures of [{Os 3 (CO) 11 } 2 (μ‐PSP)] and [Os 3 (CO) 10 (μ‐PSP)] are reported.