Carbodicarbene Bismaalkene Cations: Unravelling the Complexities of Carbene versus Carbone in Heavy Pnictogen Chemistry

We report a combined experimental and theoretical study on the first examples of carbodicarbene (CDC)‐stabilized bismuth complexes, which feature low‐coordinate cationic bismuth centers with C=Bi multiple‐bond character. Monocations [(CDC)Bi(Ph)Cl][SbF(6)] (8) and [(CDC)BiBr(2)(THF)(2)][SbF(6)] (11), dications [(CDC)Bi(Ph)][SbF(6)](2) (9) and [(CDC)BiBr(THF)(3)][NTf(2)](2) (12), and trication [(CDC)(2)Bi][NTf(2)](3) (13) have been synthesized via sequential halide abstractions from (CDC)Bi(Ph)Cl(2) (7) and (CDC)BiBr(3) (10). Notably, the dications and trication exhibit C [Formula: see text] Bi double dative bonds and thus represent unprecedented bismaalkene cations. The synthesis of these species highlights a unique non‐reductive route to C−Bi π‐bonding character. The CDC‐[Bi] complexes (7–13) were compared with related NHC‐[Bi] complexes (1, 3–6) and show substantially different structural properties. Indeed, the CDC ligand has a remarkable influence on the overall stability of the resulting low‐coordinate Bi complexes, suggesting that CDC is a superior ligand to NHC in heavy pnictogen chemistry.