Quantifying the Nitro-Radical Donating Ability of Organic Nitrating Reagents.

The ability of organic nitrating reagents to release nitro radicals underpins both classical and emerging radical-based nitration strategies. Herein, we report a comprehensive computational study of 55 representative nitrating reagents to quantify their intrinsic nitro-radical donating ability. Homolytic R─NO₂ bond dissociation enthalpies (BDEs) were computed to establish a thermodynamic scale for nitro-radical release, providing quantitative insight into reagent stability and isolability. In parallel, single-electron reduction potentials were computed to evaluate the propensity of these reagents to undergo single-electron transfer (SET)-triggered radical formation. Our results reveal that low BDE values are associated with facile nitro-radical release and poor isolability, whereas relatively high reduction potentials identify reagents capable of SET activation even when direct homolysis is energetically disfavored. By integrating these metrics, we uncover latent radical potential in several classical electrophilic nitrating reagents and identify promising candidates for future SET-enabled nitro-radical chemistry.