Hydride abstraction from monocationic
hydride bridged salts [HÂ(H<sub>2</sub>B–L)<sub>2</sub>]<sup>+</sup> [BÂ(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>]¯ (L = Lewis
base) generates an observable
primary borenium cation for L = <i>i</i>Pr<sub><i>2</i></sub>NEt, but with L = Me<sub>3</sub>N, Me<sub>2</sub>NPr, or several <i>N</i>-heterocyclic carbenes, highly reactive dicationic dimers
are formed