Theoretical study on the reaction mechanism of fluorine radical with formyl cyanide

A detailed computational study is performed on the radical-molecule reaction between the fluorine radical (F) and formylcyanide (HCOCN). At the CCSD//B3LYP/6-311G∗∗ level, the barrier of H-abstraction to provide (HF + COCN) is 15.6 kJ/mol. The barrier of the addition to form HCOCFN is 35.3 kJ/mol. However, there is no barrier of the FCHOCN's formation. Subsequently, there are two highly competitive dissociation pathways for FCHOCN: one is the formation of the direct H-extrusion product H + FCOCN, and the other is the formation of H + FCOCN via the intermediate FCOHCN. Because of the influence of the strong electron acceptor-CN to the acyl, the addition-elimination is more competitive than the direct H-transfer, in contrast to previous expectation. The present results can be useful for future experimental investigation on the title reaction.