Doubly protonated 1,3,5-trimethylenebenzene (C9H112+) and homologous C7H72+ and C8H92+ dications: Structures and unimolecular fragmentation patterns

Formation of Organoxenon Dications in the Reactions of Xenon with Dications Derived from Toluene

“…For completeness, we have also investigated association reactions of the C 7 H 7 2 + dication. [23] Such processes are only observed at elevated xenon pressures and are much less efficient than for C 7 H 6 2 + and C 7 H 8 2 + . At an elevated pressure of xenon (0.4 mtorr), at which almost all parent dications undergo reactions, traces of the organoxenon dication C 7 H 7 Xe 2 + were formed by association according to Reaction (9), whereas the vast majority of the product ions result from electron transfer [Reaction (10); see Figure S2 2 + dication generated by dissociative electron ionization of toluene with 0.1 mtorr xenon at a nominal collision energy of 0 eV.…”

General trends in dissociations of medium-sized hydrocarbon dications

“…It is assumed that under the conditions of the ion generation, complete randomization of the structure of the ions is achieved and therefore the structure of the precursor molecule itself does not significantly influence the chemical behavior of the ions generated [23]. This assumption is based on the experimental finding, which shows that the electron-ionization source provides not only enough energy for double ionization, but also the internal energies of the formed dications are high enough such that the isomerization barriers can be surmounted easily [23]. Although it may not be fully justified in all cases, the assumption of a fair amount of equilibration to the energetically lowest lying structures is reasonable and presumably sufficient as a first-order approximation for the present screening purposes about the general behavior of C m H n 2+ dications.…”

“…3). The regularity in the stabilities and fragmentation patterns can be most probably ascribed to the fact that dications with odd number of hydrogen atoms are open-shell species presumably with doublet ground state [23], whereas those with even number of hydrogen atoms are closed-shell species, most likely with singlet ground states [19,22,27,32]. The open-shell dications can therefore more easily lose a hydrogen radical, whereas the closed-shell dications preferentially eliminate an H 2 molecule.…”

“…All spectra were accumulated with the AMD-Intectra data system; 5-10 scans were averaged to improve the signal-to-noise ratio. All data were corrected for contributions of 13 C isotopes [22,23] and intensities were normalized to 1000. In addition to fragmentation patterns, the relative fractions of dissociation X are evaluated from all spectra according to Eq.…”

Bond-Forming Chemistry in the Gas-Phase Reactions of Atomic and Molecular Dications and Trications

“…55 . 60,62,[98][99][100][101] These dications can be formed not only by electron ionization in conventional GIB experiments but also by synchrotron radiation. 60,62,101 The latter ionization source offers the facility to vary the internal energy content of the reactant ions and observe the associated changes in reactivity.…”