Theoretical study on reaction mechanism of the CF radical with nitrogen dioxide

Abstract

The singlet potential energy surface of the [CFNO2] system is investigated at the B3LYP and CCSD(T) (single-point) levels to explore the possible reaction mechanism of CF radical with NO2. The top attack of C-atom of CF radical at the N-atom of NO2 molecule first forms the adduct isomer FCNO21 followed by oxygen-shift to give trans-OC(F)NO 2 and then to cis-OC(F)NO 3. Subsequently, the most favorable channel is a direct dissociation of 2 and 3 to product P1 FCO+NO. The second and third less favorable channels are direct dissociation of 3 to product P2 FNO+CO and isomerization of 3 to a complex NOFCO 4, which can easily dissociate to product P3 FON+CO, respectively. The large exothermicity released in these processes further drives most of the three products P1, P2, and P3 to take secondary dissociation to the final product P12 F+CO+NO. Another energetically allowed channel is formation of product P41NF+CO2, yet it is much less competitive than P1, P2, P3, and P12. The present calculations can well interpret one recent experimental fact that the title reaction is quite fast yet still much slower than the analogous reaction CH+NO2. Also, the results presented in this article may be useful for future product distribution analysis of the title reaction as well as for the analogous CCl and CBr reactions. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1907–1919, 2001