2025/11/24 by Atsuki Nakagami, Yoshihito Shiota, Kyosuke Fujikawa +2 · 1 voice
Medicine · Biochemistry, Genetics and Molecular Biology · Chemistry · #Nitric Oxide and Endothelin Effects #Hemoglobin structure and function #Metal-Catalyzed Oxygenation Mechanisms
paper · pdf · doi:10.1021/jacs.5c17871
openalex publication_date 2025/11/24 · openalex created_date 2025/11/25 · openalex updated_date 2026/06/22
High Resolution Image Download MS PowerPoint Slide Nitric oxide (NO) was efficiently converted to molecular nitrogen (N 2 ) in an acidic aqueous solution containing iron(III) porphyrin encapsulated in the cyclodextrin (CD) nanocavity. The supramolecular iron(III) porphyrin/CD dimer complexes (hemoCD-P and hemoCD-I), where the iron(III) is axially coordinated by a nitrogenous ligand (pyridine or imidazole) in the linker of the CD dimer, form stable 6-coordinated ferric nitrosyls FeNO 6 in acidic aqueous solution (pH ∼3). When the solution contained glycine as the buffer component, N 2 bubbles were significantly generated within several minutes at room temperature. In this system, a new N–N bond is formed on the iron-porphyrin due to the nucleophilic attack of glycine on the FeNO 6 complex. The resulting diazo compound, O═N–NH–CH 2 –COOH ⇄ HO–N═N–CH 2 –COOH, was readily hydrolyzed to generate N 2 along with a formation of α-hydroxyacid (HO–CH 2 –COOH). The reaction mechanism was evidenced by isotope-labeling experiments using 15 NO and 15 N-glycine, quantitative NMR detection of α-hydroxyacid, and theoretical calculation by DFT. The present study will provide the possibility of N–N bond formation promoted by the nucleophilic attack of amines to FeNO 6 on the native heme iron.