Studies on carbonium ions

Abstract

The interaction of styrene and its unsaturated and saturated dimers (10-5 to 1 M) with conc. sulphuric, or chlorosulphonic acids, and with anhydrous perchloric acid (10-4 to 1 M ) in methylene dich1oride, has been studied and related to the behaviour of other similar systems, such as ~-methylstyrene and its dimers.
The origin of the u.v. and visible absorption spectrum which had been wrongly attributed to the l-pheny1ethyl cation and its higher homologues was established:.
a) the 3-methyl-l-phenylindanyl cation, and its higher homologues constitute most of the ionic species formed when styrene and its dimers interact with HCI04 in CH2C1 2,. b) the 1,3-diphenyl-n-butyl cation and its higher homologues are formed when styrene and its unsaturated dimer interact with conc. H2S04 and HS0 3 Cl at low temperature and concentration, and this ion has been characterised.
The u.v. - visible and n.m.r. spectra of carboniurn ions derivable from the cyclic dimer of styrene were investigated, and spectroscopic correlations were established in the following series of diphenylalky1 cations: diphenylmethyl and ethyl, phenyl-(2' methylphenyl) methyl and ethyl, phenyl-(2'-ethylphenyl)methyl and ethyl (all l,l-ethyl), 1 ,1-dipheny1-n-butyl , l-phenylindanyl and 3-methyl-l-phenylindanyl.