A chemical dynamics, kinetics, and theoretical study on the reaction of the cyano radical (CN; X(2)Sigma+) with phenylacetylene (C6H5CCH; X(1)A1).
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.
Bennett
Chris J
CJ
Institut de Physique de Rennes, Equipe: Astrochimie Expérimentale, UMR UR1-CNRS 6251, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex, France.
Morales
Sébastien B
SB
Le Picard
Sébastien D
SD
Canosa
André
A
Sims
Ian R
IR
Shih
Y H
YH
Chang
A H H
AH
Gu
Xibin
X
Zhang
Fantong
F
Kaiser
Ralf I
RI