3,4,5,6-Tetrafluorophenylnitren-2-yl: A Ground-State Quartet Triradical

• Published in: Chemistry : a European journal Vol. 16; no. 15; pp. 4496 - 4506
• Main Authors: Grote, Dirk, Finke, Christopher, Kossmann, Simone, Neese, Frank, Sander, Wolfram
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 19-04-2010; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: Argon; Azides (organic); Chemistry; Electronic structure; EPR spectroscopy; IR spectroscopy; Irradiation; Mathematical analysis; matrix isolation; Photochemical; photochemistry; Radicals; Spectroscopy; radicals; matrix isolation; photochemistry; IR spectroscopy; EPR spectroscopy
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.200903285

The photochemistry of 2‐iodo‐3,4,5,6‐tetrafluorophenyl azide (7 d) has been investigated in argon and neon matrices at 4 K, and the products characterized by IR and EPR spectroscopy. The primary photochemical step is loss of a nitrogen molecule and formation of phenyl nitrene 1 d. Further irradiation with UV or visible light results in mixtures of 1 d with azirine 5 d′, ketenimine 6 d′, nitreno radical 2 d, and azirinyl radical 9. The relative amounts of these products strongly depend on the matrix and on the irradiation conditions. Nitreno radical 2 d with a quartet ground state was characterized by EPR spectroscopy. Electronic structure calculations in combination with the experimental results allow for a detailed understanding of the properties of this unusual new type of organic high‐spin molecules.
Quartet nitreno triradical 2 was obtained by irradiation of 2‐iodo‐3,4,5,6‐tetrafluorophenyl azide (1) in an argon matrix at 4 K and characterized by EPR spectroscopy. Electronic structure calculations in combination with the experimental results allow a detailed understanding of the properties of this unusual new type of high‐spin organic molecule.