Single-Electron Oxidation of Carbene-Coordinated Pnictinidenes-Entry into Heteroleptic Radical Cations and Metalloid Clusters.

Stable heavy main group element radicals are challenging synthetic targets. Although several strategies have been developed to stabilize such odd-electron species, the number of heavier pnictogen-centered radicals is limited. We report on a series of two-coordinated pnictogen-centered radical cations [( Me cAAC)EGa(Cl)L][B(C 6 F 5 ) 4 ] ( Me cAAC = [H 2 C(CMe 2 ) 2 NDipp]C; Dipp = 2,6- i -Pr 2 C 6 H 3 ; E = As 1 , Sb 2 , Bi 3 ; L = HC[C(Me)NDipp] 2 ) synthesized by one-electron oxidation of L(Cl)Ga-substituted pnictinidenes ( Me cAAC)EGa(Cl)L (E = As I , Sb II , Bi III ). 1 - 3 were characterized by electron paramagnetic resonance (EPR) spectroscopy and single crystal X-ray diffraction (sc-XRD) ( 1 , 2 ), while quantum chemical calculations support their description as carbene-coordinated pnictogen-centered radical cations. The low thermal stability of 3 enables access to metalloid bismuth clusters as shown by formation of [{LGa(Cl)} 3 Bi 6 ][B(C 6 F 5 ) 4 ] ( 4 ).