TY - JOUR
T1 - Dissociation of bromo- and iodotoluene molecular ions
T2 - A theoretical study
AU - Choe, Joong Chul
PY - 2008/11/15
Y1 - 2008/11/15
N2 - The potential energy surfaces (PESs) for the formation of C7H7+ from α-, o-, m-, and p-halotoluene (X = Br and I) molecular ions were determined using density functional theory molecular orbital calculations. Based on the PESs, Rice-Ramsperger-Kassel-Marcus model calculations were carried out to predict the dissociation rate constants of the molecular ions, which were then compared with previous experimental results. Kinetic analysis showed that below the threshold for the formation of tolylium ion (Tl+), the benzylium ion (Bz+) was the main product in the dissociation of all molecular ions investigated. The α-halotoluene ions produced Bz+ by direct C-X bond cleavage. The formation of Bz+ from o-halotoluene ions occurred mainly through isomerization to the alpha isomers. On the other hand, the halogenated isotoluene ions played important roles as intermediates in the formation of Bz+ from the meta and para isomers. The formation of Tl+ became important as the energy increases in the dissociations of o-, m-, and p-halotoluene ions, especially in those of o-, m-iodotoluene ions.
AB - The potential energy surfaces (PESs) for the formation of C7H7+ from α-, o-, m-, and p-halotoluene (X = Br and I) molecular ions were determined using density functional theory molecular orbital calculations. Based on the PESs, Rice-Ramsperger-Kassel-Marcus model calculations were carried out to predict the dissociation rate constants of the molecular ions, which were then compared with previous experimental results. Kinetic analysis showed that below the threshold for the formation of tolylium ion (Tl+), the benzylium ion (Bz+) was the main product in the dissociation of all molecular ions investigated. The α-halotoluene ions produced Bz+ by direct C-X bond cleavage. The formation of Bz+ from o-halotoluene ions occurred mainly through isomerization to the alpha isomers. On the other hand, the halogenated isotoluene ions played important roles as intermediates in the formation of Bz+ from the meta and para isomers. The formation of Tl+ became important as the energy increases in the dissociations of o-, m-, and p-halotoluene ions, especially in those of o-, m-iodotoluene ions.
KW - Benzylium
KW - DFT calculation
KW - RRKM calculation
KW - Tolylium
KW - Tropylium
UR - http://www.scopus.com/inward/record.url?scp=53549090697&partnerID=8YFLogxK
U2 - 10.1016/j.ijms.2008.08.003
DO - 10.1016/j.ijms.2008.08.003
M3 - Article
AN - SCOPUS:53549090697
SN - 1387-3806
VL - 278
SP - 50
EP - 58
JO - International Journal of Mass Spectrometry
JF - International Journal of Mass Spectrometry
IS - 1
ER -