Synthesis of a Counteranion‐Stabilized Bis(silylium) Ion

The preparation of a molecule with two alkyl‐tethered silylium‐ion sites from the corresponding bis(hydrosilanes) by two‐fold hydride abstraction is reported. The length of the conformationally flexible alkyl bridge is crucial as otherwise the hydride abstraction stops at the stage of a cyclic bissilylated hydronium ion. With an ethylene tether, the open form of the hydronium‐ion intermediate is energetically accessible and engages in another hydride abstraction. The resulting bis(silylium) ion has been NMR spectroscopically and structurally characterized. Related systems based on rigid naphthalen‐n,m‐diyl platforms can only be converted into the dications when the positively charged silylium‐ion units are remote from each other (1,8 versus 1,5 and 2,6).