Theoretical mechanistic study on the radical‐molecule reaction of CHCl2/CCl3 with NO2
Theoretical mechanistic study on the radical‐molecule reaction of CHCl2/CCl3 with NO2
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DOI：
10.1002/jcc.20380
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发表时间：
2006-04
影响因子：
3
通讯作者：
Jia-Xu Zhang;Zesheng Li;Jing-yao Liu;Chia-Chung Sun
中科院分区：
文献类型：
--
作者：
Jia-Xu Zhang;Zesheng Li;Jing-yao Liu;Chia-Chung Sun
The radical‐molecule reaction mechanism of CHCl2 and CCl3 with NO2 have been explored theoretically at the B3LYP/6‐311G(d,p) and MC‐QCISD (single‐point) levels. For the singlet potential energy surface (PES) of CHCl2 + NO2 reaction, the association of CHCl2 with NO2 was found to be a barrierless carbon‐to‐nitrogen approach forming an energy‐rich adduct a (HCl2CNO2) followed by isomerization to b1 (trans–cis‐HCl2CONO), which can easily interconvert to b2, b3, and b4. Subsequently, the most feasible pathway is the 1,3‐chlorine migration associated with NO1 bond cleavage of b1 leading to P1 (CHClO + ClNO). The second competitive pathway is the 1,4‐chlorine migration along with NO1 bond rupture of b4 giving rise to P2 (CHClO + ClON). Moreover, some of P1 and P2 can further dissociate to give P6 (CHClO + Cl + NO). The lesser followed competitive channel is the 1,3‐H‐shift from C to N atom along with NO1 bond rupture of b1 to form P3 (CCl2O + HNO). The concerted 1,4‐H‐shift accompanied by NO1 bond fission of b3 to product P4 (CCl2O + HON) is even much less feasible. For the singlet PES of CCl3 + NO2 reaction, the only primary product is found to be P1 (CCl2O + ClNO), which can lead to P2 (CCl2O + Cl + NO) via dissociation of ClNO. The obtained major products CHClO and CCl2O for CHCl2 + NO2 and CCl3 + NO2 reactions, respectively, are in good agreement with kinetic detection in experiment. Compared with the singlet pathways, the triplet pathways may have less contributions to both reactions. Because the rate‐determining transition state involved in the feasible pathways lie above the reactants R, the title reactions may be important in high‐temperature processes. The similarities and discrepancies among the CHnCl3−n + NO2 (n == 0–2) reactions are discussed in terms of the substitution effect. The present study may be helpful for further experimental investigation of the title reactions. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 661–671, 2006
