Growth of doubly ionized C,H,N compounds in the presence of methane

The molecular dications C(6)H(5)N(2+) generated via dissociative double ionization of 2- and 4-picoline, respectively, react with methane to form the C-C coupled products C(7)H(7)N(2+) concomitant with liberation of molecular hydrogen. Multipole-based mass spectrometric experiments and photoionization studies using synchrotron radiation demonstrate that this bond-forming reaction involves the corresponding dications in their electronic ground states. The reactions might hence be of relevance in the context of the growth of hydrocarbon species at extremely low temperatures and pressures, such as in the atmosphere of Titan. Whereas the parent [(CH(3))C(5)H(4)N](2+) dications of both picolines also show C-C coupling to a limited amount, the molecular dication of aniline, [C(6)H(5)NH(2)](2+), is almost unreactive toward methane.