Electron-impact fragmentation of triptycene. Question of bridgehead carbonium ions

A carbon-oxygen-bridged ladder-type building block for efficient donor and acceptor materials used in organic solar cells

“…However, treating 2a or 2b with p-toluenesulfonic acid (p-TsOH) in refluxing toluene gave a complicated mixture of products, in sharp contrast to the high-yield cyclization in the triptycene case. The inefficient cyclization results from the much easier formation of tertiary carbocations in 2a or 2b than in triptycene alcohol [29,30]. The colorless solution of 2a or 2b immediately turned into dark red after p-TsOH being added, suggesting carbocation formation.…”

Intramolecular hydrogen transfer in mass spectra. I. Rearrangements in aliphatic hydrocarbons and aromatic compounds

“…Returning to the question of hydrogen scrambling in aromatic systems, scrambling of aromatic hydrogens is also observed in naphthalene (11),199 phenanthrene (12),199 and biphenyl (13).213 Other fragmentations which must involve hydrogen rearrangement are observed for naphthalene and azulene,214 doubly charged naphthalene,208,211 phenanthrene,215 triptycene, 216,217 triply charged biphenyl,211,218 triply charged 9,10-diphénylanthracene,219,220 singly charged 9,10-diphenylanthracene,220 and the polyphenyls.221 A theoretical treatment of rearrangements in biphenyl has appeared. 222 Randomization of the aromatic hydrogens also occurs in various heterocyclic analogs of benzene.…”

Mass spectrometry

“…Mass-spectrometric studies have been undertaken on some triarylethylenes (448) and some acetylenic compounds (444,445).…”

“…The stability of aromatic hydrocarbons under electron bombardment (446) and the structures of (M-43) ions in the mass spectra of substituted nbutylbenzenes (447) have been subjects of investigation. The (M-H) ion in the mass spectrum of triptycene arises by loss of hydrogen originally bonded to one of the aromatic rings, rather than from loss of a bridgehead hydrogen atom (448) • The mass spectra of fulvenes (449) , of 9,10-dihydrophenanthrene (450) , of some lignans of the 1-phenyl-1,2,3,4-tetrahydronaphthalene series (451) , and of tricyclic hydrocarbons of high molecular weight (lubricating oil range) (452) have been reported.…”