Synthesis and Reactivity of Ruthenium-Antimony Carbonyl Clusters

The reaction of Na[HRu3(CO)11] (2) with SbPh2Cl in dry tetrahydrofuran (THF) afforded the cluster Ru3(CO)10(μ‐H)(μ‐SbPh2) (3); in dry dichloromethane (DCM), the six‐membered ring Ru6(CO)20(μ‐H)2(μ‐SbPh2)2 (4) was obtained instead. The trimethylamine N‐oxide (TMNO) activated reaction of Ru3(CO)12 (1) with distibine Sb2Ph4 produced Ru3(CO)10(μ‐SbPh2)2 (6) through an Sb–Sb bond oxidative addition. Cluster 6 is fluxional through Ru–Ru bond isomerization. In contrast, its group 15 monosubstituted derivatives Ru3(CO)9(μ‐SbPh2)2(L) (7, L = phosphane, arsine or stibine) or the disubstituted derivatives Ru3(CO)8(μ‐SbPh2)2(L)2 (8) did not exhibit such fluxionality. Instead, isomerization through a turnstile mechanism involving the group 15 ligand occurred. The treatment of 6 with SbPh2Cl afforded the fused‐ring clusters Ru3(CO)9(μ‐SbPh2)3(Cl) (9) and Ru3(CO)8(μ‐SbPh2)3(Cl)(SbPh2CH2Cl) (10). A series of ruthenium–antimony carbonyl clusters are prepared by the oxidative addition of Sb–Cl or Sb–Sb bonds to lightly stabilized ruthenium carbonyl clusters. Their solid‐ and solution‐state structures are studied in detail by X‐ray crystallography and variable‐temperature multinuclear NMR experiments, respectively.