The Arene-Stabilized η -Pentamethylcyclopentadienyl Arsenic Dication [(η -Cp*)As(toluene)].

Double chloride abstraction of Cp*AsCl gives the dicationic arsenic species [(η -Cp*)As(tol)][B(C F ) ] (2) (tol=toluene). This species is shown to exhibit Lewis super acidity by the Gutmann-Beckett test and by fluoride abstraction from [NBu ][SbF ]. Species 2 participates in the FLP activation of THF affording [(η -Cp*)AsO(CH ) (THF)][B(C F ) ] (5). The reaction of 2 with PMe or dppe generates [(Me P) As][B(C F ) ] (6) and [(σ-Cp*)PMe ][B(C F ) ] (7), or [(dppe)As][B(C F ) ] (8) and [(dppe)(σ-Cp*) ][B(C F ) ] (9), respectively, through a facile cleavage of C-As bonds, thus showcasing unusual reactivity of this unique As-containing compound.