Interaction between Aromatics and Zinc Chloride. III. The Dissociation of Triphenylmethane and 9,10-Dihydroanthracene into Ions

Abstract

Abstract Triphenylmethane and 9,10-dihydroanthracene were found to produce colored complexes when placed in contact with molten zinc chloride or with solid zinc chloride pulverized or supported on porous Vycor glass. The triphenylmethane complex gave the same electronic absorption spectrum as that of the triphenylmethyl cation generated by contact with silica-alumina and BF3 on silica. The 9,10-dihydroanthracene complex exhibited the same electronic absorption band as that of the 9-anthracenium ion produced by the reaction of anthracene with concd H2SO4. The reaction of the triphenylmethane complex with deuterium gas provided HD gas and (C6H5)3CD. Similarly, the 9,10-dihydroanthracene complex and deuterium gas produced HD gas and 9,10-dihydroanthracene-9-d. Furthermore, their colored complexes on the supported zinc chloride gave a very weak IR absorption band at about 1720 cm−1, which is interpreted as corresponding to the formation of a Zn–H bond. These observations led us to conclude that triphenylmethane and 9,10-dihydroanthracene dissociate into ions . upon contact with zinc chloride: (C6H5)3CH+nZnCl2 \ightleftarrows (C6H5)3C+(ZnCl2)n−H (Remark: Graphics omitted.)