Oxidative addition of halogen across an Os-Os or Os-Sb bond: Formation of five-membered osmium-antimony carbonyl rings

Abstract

Halogenation of the cluster Os3(CO)10(μ-SbPh2)2, 2, with PhICl2 or I2 affords the five-membered metallacyclic rings Os3(Cl)2(CO)10(μ-SbPh2)2, 3d and Os3(I)2(CO)10(μ-SbPh2)2, 3d-I, respectively, via oxidative addition across an OsOs bond. The reaction of 2 with SbPh2Cl or SbPh2H gives the 3,5-fused rings Os3(X)(CO)9(μ-SbPh2)3, (X = Cl, 4a; H, 4b), respectively. Halogenation of 4 with PhICl2 gives the five-membered metallacyclic rings Os3(Cl)(X)(CO)9(SbPh2Cl)(μ-SbPh2)2 (X = Cl, 5a; H, 5b) via oxidative addition across an OsSb bond. The analogous reaction with I2 also results in oxidative addition across an OsSb bond, but this is followed by displacement of SbPh2I to afford a five-membered metallacycle containing a μ-I ligand, viz., Os3(μ-I)(X)(CO)9(μ-SbPh2)2 (X = Cl, 7a, H, 7b).