Experimental and Theoretical Study on the Gas-Phase Reactions of Germyl Radicals with NF: Homolytic Substitution at the Nitrogen Atom vs Fluorine Abstraction.

In this paper, we report on the unexplored reaction mechanisms of bimolecular homolytic substitution (S2) between GeH radicals and the nitrogen atom of NF. The S2 reactions are studied both experimentally and theoretically with ab initio and density functional theory (DFT) calculations. The experimental results of X-ray irradiation of mixtures of GeH and NF show the formation of GeH-NF and GeH-F. The trend of product yields as a function of the increase in GeH partial pressure in the irradiated mixtures evidences the predominant role of GeH radicals. Particularly, the S2 mechanism can be hypothesized for the reaction between GeH radicals and NF molecules leading to GeH-NF. This mechanism is further confirmed by the increase in GeH-NF yield observed if O is added, as a radical scavenger, to the reaction mixture. In agreement with the experimental data, from the calculations performed at the CCSD(T) and G3B3 levels of theory, we observe that the GeH-NF product actually occurs from a bimolecular homolytic substitution by the GeH radical, which attacks the N atom of NF, and this reaction is in competition with the fluorine abstraction reaction leading to GeHF, even if other mechanisms may be involved in the formation of this product.