Year: 2025
Type: article
Abstract: The photochemical properties and reaction mechanisms of a series of hypervalent iodoazide compounds (R–IN 3 ) were investigated, with substituents (−CH 3, −H, −CF 3 ) tuning the electronic density of the phenyl ring. With the help of UV irradiation, ultrafast time-resolved spectroscopy, and density functional theory (DFT) calculations, we elucidated the mechanisms of azide radical (N 3 • ) release and its subsequent reactivity. UV–vis spectroscopy reveals that the photoconversion rates follow the trend CH 3 > H > CF 3, aligning with DFT-calculated Δ G values for ring-opening transitions. Homolytic cleavage of the I–N bond is identified as the dominant pathway for N 3 • generation upon UV irradiation, occurring within 400 fs. The released azide radicals react with the solvent molecules, while the iodo radical R–I C • fragments undergo a thermodynamically uphill lactone ring-opening (RO) reaction and subsequent hydrogen atom abstraction from the solvent to form carboxylic acids R–I–COOH, as validated by NMR and IR spectroscopy. The study also highlights the role of substituents in influencing reaction kinetics and intermediate stability, with electron-donating groups accelerating the release of the N 3 • species. This work bridges experimental observations with computational predictions, offering a foundation for future advancements in azide-based reactions and materials.
Institutions: Argonne National Laboratory, University of Illinois Chicago
Language: English
Subfield: Physical and Theoretical Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
Funders: U.S. Department of Energy, University of Illinois at Urbana-Champaign, National Nuclear Security Administration, University of Illinois at Chicago, Army Research Office, Argonne National Laboratory, Life Sciences Division, Army Research Office, Department of Energy National Nuclear Security Administration Laboratory Residency Graduate Fellowship
OpenAlex ID: W4411430178