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 Ru-3(CO)(10)(-H)(-SbPh2) (3); in dry dichloromethane (DCM), the six-membered ring Ru-6(CO)(20)(-H)(2)(-SbPh2)(2) (4) was obtained instead. The trimethylamine N-oxide (TMNO) activated reaction of Ru-3(CO)(12) (1) with distibine Sb2Ph4 produced Ru-3(CO)(10)(-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 Ru-3(CO)(9)(-SbPh2)(2)(L) (7, L = phosphane, arsine or stibine) or the disubstituted derivatives Ru-3(CO)(8)(-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 Ru-3(CO)(9)(-SbPh2)(3)(Cl) (9) and Ru-3(CO)(8)(-SbPh2)(3)(Cl)(SbPh2CH2Cl) (10).