Theoretical study on reaction mechanism of the ketenylidene radical with nitrogen dioxide.
The complex doublet potential-energy surface for the reaction of CCO with NO2, including 8 minimum isomers and 17 transition states, is explored theoretically using the coupled cluster and density functional theory. The association of CCO with NO2 was found to be a barrierless process forming an energy-rich adduct a (OCCNO2) followed by oxygen shift to give b (O2CCNO). Our results show that the product P1 (CO2 + CNO) is the major product with absolute yield, while the product P4 (2CO + NO) is the minor product with less abundance. The other products may be undetectable. The product P1 (CO2 + CNO) can be obtained through R --> a --> b --> P1 (CO2 + CNO), whereas the product P4 (2CO + NO) can be obtained through two channels R --> a--> b --> c --> (d, g) --> P2 (OCNO + CO) --> P4 (2CO + NO) and R --> a --> b --> f --> P3 (c-OCC-O + NO) --> P4 (2CO + NO). Because the intermediates and transition states involved in the above three channels are all lower than the reactants in energy, the CCO + NO2 reaction is expected to be rapid, which is consistent with the experimental measurement in quality. The present study may be helpful for further experimental investigation of the title reaction.
Zhang
Jia-xu
JX
Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun 130023, People's Republic of China.
Liu
Jing-yao
JY
Li
Ze-sheng
ZS
Sun
Chia-chung
CC