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(C6 F5 )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(C6 F5 )4 ]2 (5). The reaction of 2 with PMe3 or dppe generates [(Me3 P)2 As][B(C6 F5 )4 ] (6) and [(σ-Cp*)PMe3 ][B(C6 F5 )4 ] (7), or [(dppe)As][B(C6 F5 )4 ] (8) and [(dppe)(σ-Cp*)2 ][B(C6 F5 )4 ]2 (9), respectively, through a facile cleavage of C-As bonds, thus showcasing unusual reactivity of this unique As-containing compound.