"Activated Borane": A Porous Borane Cluster Polymer as an Efficient Lewis Acid-Based Catalyst.

Borane cluster-based porous covalent networks, named activated borane ( ActB ), were prepared by cothermolysis of decaborane(14) ( nido -B 10 H 14 ) and selected hydrocarbons (toluene, ActB-Tol; cyclohexane, ActB- cy Hx ; and n -hexane, ActB- n Hx ) under anaerobic conditions. These amorphous solid powders exhibit different textural and Lewis acid (LA) properties that vary depending on the nature of the constituent organic linker. For ActB-Tol , its LA strength even approaches that of the commonly used molecular LA, B(C 6 F 5 ) 3 . Most notably, ActB s can act as heterogeneous LA catalysts in hydrosilylation/deoxygenation reactions with various carbonyl substrates as well as in the gas-phase dehydration of ethanol. These studies reveal the potential of ActB s in catalytic applications, showing (a) the possibility for tuning catalytic reaction outcomes (selectivity) in hydrosilylation/deoxygenation reactions by changing the material's composition and (b) the very high activity toward ethanol dehydration that exceeds the commonly used γ-Al 2 O 3 by achieving a stable conversion of ∼93% with a selectivity for ethylene production of ∼78% during a 17 h continuous period on stream at 240 °C.