OXIDATIVE AND ELECTROPHILIC CHEMISTRY (PROTONATION, ACETYLATION, TRIMETHYLSILYLATION) OF OCTAMETHYLBIPHENYLENE AND DODECAMETHYLBINAPHTHYLENE - A MASS-SPECTRAL AND SUPERACID SOLUTION STUDY

A mass spectral study of the cations formed by oxidation, protonation, acetylation (MeCO+), trimethylsilylation (Me3Si+), and trifluoroacety lation-trifluoromethylation (CF3CO+-CF3+) of octamethylbiphenylene 4 ( fully methylated [2]phenylene) and dodecamethylbinaphthylene 5 (fully methylated dibenzo[b,h]biphenylene) is reported, and the decomposition pathways of the resulting ions are probed by tandem mass spectrometry . Collisional decompositions of the acylation and trimethylsilylation monocations are selective towards charge retention at the aromatic moi ety. A bis-silylated monocation was formed via 5. Doubly charged ions were only observed in oxidation reactions (EI/MS). The greater solutio n stability of the arenium ion of ipso protonation of 5 as compared to 4 is borne out by its direct observation in FSO3H-SO2ClF at low tempe rature.