Stabilization of a bismuth–bismuth double bond by anionic N-heterocyclic carbenes

Abstract

The bismuth dichloride complex (WCA-IDipp)BiCl₂, which bears an anionic N-heterocyclic carbene ligand with a weakly coordinating borate moiety (WCA-IDipp, WCA = B(C₆F₅)₃, IDipp = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene), was prepared by salt metathesis reaction between BiCl₃ and the lithium salt (WCA-IDipp)Li·toluene. Subsequent two-electron reduction with 1,4-bis(trimethylsilyl)-1,4-dihydropyrazine afforded the dibismuthene (WCA-IDipp)₂Bi₂, which displays a bismuth–bismuth double bond.