Formation of Cup-Shaped Metallic Clusters via B−H Activation at the B(3)/B(6) Site of an ortho-Carborane-1,2-dichalcogenolato Ligand

Dimetallic complexes {Cp*Ir[E₂C₂(B₉H₉)][(cod)Ir(OCH₃)]} (E = S, 3a; E = Se, 3b) and {Cp^*Ir[E₂C₂(B₁₀H₉)][(cod)Ir]} (E = S, 4a; E = Se, 4b) were synthesized by the reaction of half-sandwich complexes Cp*Ir[E₂C₂(B₁₀H₁₀)] (E = S, 1a; Se, 1b) with 2 equiv of [Ir(cod)(μ-OMe)]₂ (2-Ir). Analogous reactions of 1a with [Rh(cod)(μ-OMe)]₂ (2-Rh) were investigated, and three complexes, {Cp*Ir[S₂C₂(B₉H₉)][(cod)Rh(OCH₃)]} (5a), {Cp*Ir[S₂C₂(B₁₀H₁₀)][(cod)Rh]} (6a), and {Cp*Ir[S₂C₂(B₁₀H₉)][(cod)Rh]} (7a), were obtained. By comparing the two reactions, the routes of metal-induced B−H activation at B(3)/B(6) of the ortho-carborane-1,2-dichalcogenolato ligand were investigated. These nido-carborane complexes such as 3a, 3b, and 5a contain intercluster metal−metal bonds. Moreover, the V-shaped trimetallic units {(cod)Ir[E₂C₂(B₉H₈)][(cod)Ir(OCH₃)][(C₈H₁₃)Ir]} (E = S, 9a; Se, 9b) have been constructed through the M₂-nido-carborane complexes {(cod)Ir[E₂C₂(B₉H₉)][(cod)Ir(OCH₃)]} (E = S, 8a; Se, 8b). Complexes 3−10 were characterized by NMR spectroscopy (¹H, ¹¹B NMR), and X-ray structural analyses were reported for complexes 3a, 3b, 4a, 5a, 6a, 8a, 9b, and 10b.