Stable carbocations. Part 19. A kinetic study of the fragmentation of ferrocenyldiarylmethylium ions in aqueous acidic acetonitrile

Abstract

Rate constants have been measured for the spontaneous fragmentation of ferrocenyldiarylmethylium ions FcCAr¹Ar² in aqueous acidic acetonitrile giving 6,6-diarylpentafulvenes. The reaction rate is sensitive to the presence of para-substituents (OMe or CF₃) in the aryl rings and to change in the ionic strength of the medium. Factors influencing fragmentation of ferrocenylcarbocations are discussed.