title: A chemical dynamics, kinetics, and theoretical study on the reaction of the cyano radical (CN; X(2)Sigma+) with phenylacetylene (C6H5CCH; X(1)A1).
abstract: The chemical reaction dynamics to form o-, m-, and p-cyanophenylacetylene via the neutral-neutral reaction of ground state cyano radicals with phenylacetylene and D(1)-phenylacetylene were investigated in crossed beam experiments; these studies were combined with kinetics measurements of the rate coefficients at temperatures of 123, 200, and 298 K and supplemented by electronic structure calculations. The data suggest that the reaction is initiated by a barrier-less addition of the electrophilic cyano radical to the o-, m-, or p-position of the aromatic ring. The eventually fragmented via atomic hydrogen elimination to form o-, m-, and p-cyanophenylacetylene via tight exit transition states with the hydrogen atom being ejected almost perpendicularly to the molecular plane of the rotating complex. The overall reaction to form o-, m-, and p-cyanophenylacetylene was found to be exoergic by 89 +/- 18 kJ mol(-1) in nice agreement with the calculations. The o-cyanophenylacetylene isomer is of particular relevance as a potential building block to the formation of nitrogen-substituted didehydronaphthalene molecules in analogy to didehydronaphthalene in Titan's aerosol layers--a pathway hitherto neglected by the planetary science modeling community.
authors.affiliation: Institut de Physique de Rennes, Equipe: Astrochimie Expérimentale, UMR UR1-CNRS 6251, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex, France.
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Bennett
authors.forename: Sébastien B
authors.initials: SB
authors.lastname: Morales
authors.forename: Sébastien D
authors.initials: SD
authors.lastname: Le Picard
authors.forename: André
authors.initials: A
authors.lastname: Canosa
authors.forename: Ian R
authors.initials: IR
authors.lastname: Sims
authors.forename: Y H
authors.initials: YH
authors.lastname: Shih
authors.forename: A H H
authors.initials: AH
authors.lastname: Chang
authors.forename: Xibin
authors.initials: X
authors.lastname: Gu
authors.forename: Fantong
authors.initials: F
authors.lastname: Zhang
authors.forename: Ralf I
authors.initials: RI
authors.lastname: Kaiser