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Interaction between Molecular Oxygen and Nitroxide Radicals: A Search for a Reversible Complex
Author(s) -
Moscatelli Alberto,
Ottaviani M. Francesca,
Adam Waldemar,
Buchachenko Anatoly,
Jockusch Steffen,
Turro Nicholas J.
Publication year - 2006
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200690224
Subject(s) - nitroxide mediated radical polymerization , chemistry , electron paramagnetic resonance , spins , radical , oxygen , supramolecular chemistry , molecular oxygen , photochemistry , spin (aerodynamics) , molecule , polymerization , nuclear magnetic resonance , organic chemistry , radical polymerization , thermodynamics , polymer , condensed matter physics , physics
At high concentrations of oxygen, the EPR spectrum of the nitroxide radical 4‐oxo‐TEMPO (= 4‐oxo‐2,2,6,6‐tetramethylpiperidin‐1‐yloxy) is found to broaden significantly. In addition to the expected broadening, double integration of the EPR signals indicates that a significant fraction of the nitroxide spins has ‘disappeared’. In perfluoro(2‐butyltetrahydrofuran) at 273 K, the extent of diminution of the EPR signal intensity is ca. 20%. The results are analyzed in terms of collision and supramolecular complexes between oxygen and 4‐oxo‐TEMPO. It is concluded that a supramolecular complex is responsible for the observed phenomenon.