Cage Opening of a Carborane Ligand by Metal Cluster Complexes

The reaction of Os3(CO)10(NCMe)2 with closo‐o‐C2B10H10 has yielded two interconvertible isomers Os3(CO)9(μ3‐4,5,9‐C2B10H8)(μ‐H)2 (1 a) and Os3(CO)9(μ3‐3,4,8‐C2B10H8)(μ‐H)2 (1 b) formed by the loss of the two NCMe ligands and one CO ligand from the Os3 cluster. Two BH bonds of the o‐C2B10H10 were activated in its addition to the osmium cluster. A second triosmium cluster was added to the 1 a/1 b mixture to yield the complex Os3(CO)9(μ‐H)2(μ3‐4,5,9‐μ3‐7,11,12‐C2B10H7)Os3(CO)9(μ‐H)3 (2) that contains two triosmium triangles attached to the same carborane cage. When heated, 2 was transformed to the complex Os3(CO)9(μ‐H)(μ3‐3,4,8‐μ3‐7,11,12‐C2B10H8)Os3(CO)9(μ‐H) (3) by a novel opening of the carborane cage with loss of H2. Be open with your carboranes! Complex Os3(CO)9(μ‐H)2(μ3‐4,5,9‐μ3‐7,11,12‐C2B10H7)Os3(CO)9(μ‐H)3 (see figure) was synthesized; it contains two triosmium triangles attached to the same carborane cage. When heated, this complex is transformed to complex Os3(CO)9(μ‐H)(μ3‐3,4,8‐μ3‐7,11,12‐C2B10H8)Os3(CO)9(μ‐H) by opening of the carborane cage by the metal clusters on its surface.