Carbodicarbene Bismaalkene Cations: Unravelling the Complexities of Carbene versus Carbone in Heavy Pnictogen Chemistry
Jacob E. Walley, Levi S. Warring, Guocang Wang, Diane A. Dickie, Sudip Pan, Gernot Frenking, Robert J. Gilliard
Abstract
Abstract 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 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.