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, eta(2)-sigma-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 Ph-2(H)C-OSiEt3.