TY - JOUR
T1 - Dioxygen
T2 - What Makes This Triplet Diradical Kinetically Persistent?
AU - Borden, Weston Thatcher
AU - Hoffmann, Roald
AU - Stuyver, Thijs
AU - Chen, Bo
N1 - Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/7/5
Y1 - 2017/7/5
N2 - Experimental heats of formation and enthalpies obtained from G4 calculations both find that the resonance stabilization of the two unpaired electrons in triplet O2, relative to the unpaired electrons in two hydroxyl radicals, amounts to 100 kcal/mol. The origin of this huge stabilization energy is described within the contexts of both molecular orbital (MO) and valence-bond (VB) theory. Although O2 is a triplet diradical, the thermodynamic unfavorability of both its hydrogen atom abstraction and oligomerization reactions can be attributed to its very large resonance stabilization energy. The unreactivity of O2 toward both these modes of self-destruction maintains its abundance in the ecosphere and thus its availability to support aerobic life. However, despite the resonance stabilization of the ? system of triplet O2, the weakness of the O-O σ bond makes reactions of O2, which eventually lead to cleavage of this bond, very favorable thermodynamically.
AB - Experimental heats of formation and enthalpies obtained from G4 calculations both find that the resonance stabilization of the two unpaired electrons in triplet O2, relative to the unpaired electrons in two hydroxyl radicals, amounts to 100 kcal/mol. The origin of this huge stabilization energy is described within the contexts of both molecular orbital (MO) and valence-bond (VB) theory. Although O2 is a triplet diradical, the thermodynamic unfavorability of both its hydrogen atom abstraction and oligomerization reactions can be attributed to its very large resonance stabilization energy. The unreactivity of O2 toward both these modes of self-destruction maintains its abundance in the ecosphere and thus its availability to support aerobic life. However, despite the resonance stabilization of the ? system of triplet O2, the weakness of the O-O σ bond makes reactions of O2, which eventually lead to cleavage of this bond, very favorable thermodynamically.
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U2 - 10.1021/jacs.7b04232
DO - 10.1021/jacs.7b04232
M3 - Article
C2 - 28613073
AN - SCOPUS:85022065922
SN - 0002-7863
VL - 139
SP - 9010
EP - 9018
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 26
ER -