Synthesis of a Bis(N-heterocyclic carbene)palladium Complex via Oxidative Addition of a C−C Bond in a Biimidazolium Ion

The formation of a cyclophane−NHC complex of Pd(II) via oxidative addition of a C−C bond in a bridged biimidazolium ion to Pd(0) is described. The active Pd(0) species appears to be [Pd(PPh3)2Br]-. Simple (unbridged) biimidazolium ions do not form NHC complexes under similar conditions.