The role of bridged structures in the mechanism of the reaction between chlorine atom and ethylene

Citation
P. Brana et al., The role of bridged structures in the mechanism of the reaction between chlorine atom and ethylene, CHEM P LETT, 325(5-6), 2000, pp. 693-697
Citations number
20
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
CHEMICAL PHYSICS LETTERS
ISSN journal
00092614 → ACNP
Volume
325
Issue
5-6
Year of publication
2000
Pages
693 - 697
Database
ISI
SICI code
0009-2614(20000804)325:5-6<693:TROBSI>2.0.ZU;2-X
Abstract
The potential energy surface for the reaction between a chlorine atom and e thylene was extensively explored by using ab initio methodologies. Two diff erent routes for the 1,2 migration of the chlorine atom were identified. On e of them involves a C-2v (B-2(2)) transition structure (TSsb) that directl y connects two equivalent structures (P and P') of the 2-chloroethyl radica l with the chlorine atom attached either to C1 (P) or to C2 (P') carbon ato ms in ethylene (shuttling motion). In the second pathway, the 2-chloroethyl radical (P) coverts into a C-2v ((2)A(1)) intermediate (I-add) through a C -s ((2)A') transition structure (TSadd). Then I-add leads to the 2-chloroet hyl radical (P') through a transition structure equivalent to TSadd (TSadd' ). The 'indirect shuttling motion' described along this latter route is not ably lower in energy and allows one to rationalize some mechanistic aspects experimentally observed in reactions involving haloethyl radicals. (C) 200 0 Elsevier Science B.V. All rights reserved.