The Arene‐Stabilized η5‐Pentamethylcyclopentadienyl Arsenic Dication [(η5‐Cp*)As(toluene)]2+

Double chloride abstraction of Cp*AsCl₂ gives the dicationic arsenic species (η⁵‐Cp*)As(tol)]B(C₆F₅)₄]₂ ( 2 ) (tol=toluene). This species is shown to exhibit Lewis super acidity by the Gutmann–Beckett test and by fluoride abstraction from NBu₄]SbF₆]. Species 2 participates in the FLP activation of THF affording (η²‐Cp*)AsO(CH₂)₄(THF)]B(C₆F₅)₄]₂ ( 5 ). The reaction of 2 with PMe₃ or dppe generates (Me₃P)₂As]B(C₆F₅)₄] ( 6 ) and (σ‐Cp*)PMe₃]B(C₆F₅)₄] ( 7 ), or (dppe)As]B(C₆F₅)₄] ( 8 ) and (dppe)(σ‐Cp*)₂]B(C₆F₅)₄]₂ ( 9 ), respectively, through a facile cleavage of C?As bonds, thus showcasing unusual reactivity of this unique As‐containing compound.