Switching from Heteronuclear Allyl Cations to Vinyl Cations by Using a Chemical Charge Trap.

Halide abstraction of the carbene-coordinated pnictinidenes ( Me cAAC)EGa(Cl)L (E = As 1 , Sb 2 , Bi 3 , Me cAAC = [H 2 C(CMe 2 ) 2 NDipp]C; L = HC[C(Me)NDipp] 2 ; Dipp = 2,6- i -Pr 2 C 6 H 3 ) yielded the series of cationic group 15 compounds [( Me cAAC)EGaL][Al(OR F ) 4 ] (E = As 4 , Sb 5 ; Al(OR F ) 4 = Al(OC(CF 3 ) 3 ) 4 ) and [( Me cAAC)EGaL][B(Ar F ) 4 ] (E = Sb 6 , Bi 7 ; B(Ar F ) 4 = B[C 6 H 3 (CF 3 ) 2 ] 4 ), which were characterized by heteronuclear NMR spectroscopy and sc-XRD. The electronic nature of the cations [( Me cAAC)EGaL] + is controlled by the central pnictogen atom, according to quantum chemical calculations. The calculations furthermore demonstrated that compounds containing the lighter pnictogens (E = N, P) are best described as heteronuclear allyl cations, whereas heavier pnictogen atoms (E = As, Sb, Bi) serve as a trap for the positive charge, resulting in carbene-stabilized heterovinyl-type structures.