Thermolysis of the Osmium−Antimony Clusters Os₃(CO)₁₁(SbMe₂Ar): Higher Nuclearity Clusters and Arrested Ortho Metalation

Thermolysis of the clusters Os3(CO)11(SbMe2Ar) (1, where Ar = Ph (b), o-tolyl (c), p-tolyl (d)), in refluxing octane gave the clusters Os3(μ-SbMe2)(μ-H)(μ3,η2-C6H3R)(CO)9 (2, where R = H (b), Me (c)), in good yields; both tolyl derivatives gave the same 4-substituted phenylene cluster. Among the minor products also isolated from the thermolysis of 1b were the higher nuclearity clusters Os6(μ3-SbMe)(μ3,η2-C6H4)(CO)20 (4) and Os6(μ4-Sb)(μ-SbMe2)(μ-H)(μ3,η2-C6H4)2(CH3)(CO)16 (5), which contains an Os−CH3 moiety. Thermolysis of the 3,5-xylyl analogue Os3(CO)11{SbMe2(3,5-Me2C6H3)} (1f), on the other hand, gave the unusual species Os3(μ-SbMe2)(μ3,η1:η2:η2-C6H3Me2)(CO)9 (6), in which ortho metalation of the xylyl ring has apparently been arrested.