Generation and aromaticity of 2-silaimidazolium ion, a new (pi)-conjugated silylium ion

A novel cationic silaaromatic, 2-silaimidazolium cation (5), was synthesized by chloride abstraction from the corresponding chlorosilane (4) with [Et3Si(benzene)]+· TPFPB–(TPFPB–= tetrakis(pentafluorophenyl)borate); cation 5 exists as a free silylium cation in solution due to bulky substituents on the five-membered ring.