Crystalline Divinyldiarsene Radical Cations and Dications

The divinyldiarsene radical cations [{(NHC)C(Ph)}As](2)(GaCl(4)) (NHC=IPr: C{(NDipp)CH}(2) 3; SIPr: C{(NDipp)CH(2)}(2) 4; Dipp=2,6‐iPr(2)C(6)H(3)) and dications [{(NHC)C(Ph)}As](2)(GaCl(4))(2) (NHC=IPr 5; SIPr 6) are readily accessible as crystalline solids on sequential one‐electron oxidation of the corresponding divinyldiarsenes [{(NHC)C(Ph)}As](2) (NHC=IPr 1; SIPr 2) with GaCl(3). Compounds 3–6 have been characterized by X‐ray diffraction, cyclic voltammetry, EPR/NMR spectroscopy, and UV/vis absorption spectroscopy as well as DFT calculations. The sequential removal of one electron from the HOMO, that is mainly the As−As π‐bond, of 1 and 2 leads to successive elongation of the As=As bond and contraction of the C−As bonds from 1/2→3/4→5/6. The UV/vis spectrum of 3 and 4 each exhibits a strong absorption in the visible region associated with SOMO‐related transitions. The EPR spectrum of 3 and 4 each shows a broadened septet owing to coupling of the unpaired electron with two (75)As (I=3/2) nuclei.