Reactivity of C9H n 2+ dications with methane

Abstract: The reactivities of C9H x 2+ dications (x =6–8) generated by electron ionization (EI) of indene, 1-phenylpropyne, and 3-phenylpropyne, respectively, were studied in thermal collisions with methane. The most reactive dications correspond to dehydrogenated C9H6 2+, which show about 65% yield of C–C coupling products. The yield of coupling products in the reactions of radical dications C9H7 2+ drop to about 15% and the reactivity is dominated by electron transfer and charge-separation processes. The reaction between C9H8 2+ and methane leads mostly to proton transfer. There are differences between reactivities of analogous dications generated from different neutral precursors and therefore it can be stated that even dications generated by EI retain a partial memory of the structure of the neutral precursor. [Copyright &y& Elsevier]