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 numberof heavier pnictogen-centered radicals is limited. We report on a series of two-coordinatedpnictogen-centered radical cations [(MecAAC)EGa(Cl)L][B(C6F5)4](MecAAC = [H2C-(CMe2)2NDipp]C; Dipp = 2,6-i-Pr2C6H3;E=As1,Sb2,Bi3; L = HC[C(Me)NDipp]2)synthesized by one-electron oxidation of L(Cl)Ga-substituted pnictinidenes (MecAAC)EGa(Cl)L(E = AsI,SbII,BiIII).1-3were characterized by electron paramagnetic resonance (EPR)spectroscopy and single crystal X-ray diffraction (sc-XRD) (1,2), while quantum chemicalcalculations support their description as carbene-coordinated pnictogen-centered radical cations.The low thermal stability of3enables access to metalloid bismuth clusters as shown by formationof [{LGa(Cl)}3Bi6][B(C6F5)4](4).

Automated summary

Stable heavy main group element radicals are challenging to synthesize. Researchers have successfully synthesized a series of two-coordinated pnictogen-centered radical cations by developing new strategies, and characterized and validated them.