Kinetically Stabilized Diarylpnictogenium Ions.

The newly prepared and fully characterized stibenium and bismuthenium ions [R ind MesE] + (E=Sb, Bi; R ind =dispiro[fluorene-9,3'-(1',1',7',7'-tetramethyl-s-hydrindacen-4'-yl)-5',9''-fluorene) were rigorously compared to the previously communicated phosphenium and arsenium ions (E=P, As) as well as the bis(m-terphenyl) pnictogenium ions [(2,6-Mes 2 C 6 H 3 ) 2 E] + (E=Sb, Bi). It is demonstrated that the choice of the aryl substituents dramatically effects the molecular structures (e. g. the primary E-C bond lengths) and the electronic structures (e. g. the energy of the LUMOs).