The Chemistry of [1,1′-bis(o-Carboranyl)]Borane η²-σ-Silane Adduct

We report here a new route for the preparation of [1,1′-bis(o-carboranyl)]borane, a 3D analogue of 9-borafluorene, η²-σ-silane adduct (1-H-SiEt₃) in high yields (>80 %). The nature of B−H−Si bonding was studied by density functional theory (DFT) computations. Preliminary reactivity study of 1-H-SiEt₃ with small molecules was carried out. Interestingly, 1-H-SiEt₃ reacts with benzophenone in hexane producing the deoxygenation product Ph₂CH₂. While in benzene, 1-H-SiEt₃ reacts with benzophenone leading to mixture of Ph₂CH₂ and Ph₃CH (3 : 1). Ph₃CH is formed via addition of benzene to the carbonyl followed by deoxygenation. In contrast, the reaction of benzophenone with Et₃SiH in presence of a catalytic amount of 1-H-SiEt₃ leads to hydrosilylation product Ph₂(H)C−OSiEt₃.