P. Marsal et al., Thermal stability of O-H and O-alkyl bonds in N-alkoxyamines. A density functional theory approach, J PHYS CH A, 103(15), 1999, pp. 2899-2905
The O-C bond dissociation energy (Delta H(r)degrees(T)) in alkoxyamines app
ears to play a key role in the nitroxide-mediated living free radical polym
erizations, and an efficient control of the process can be achieved for Del
ta H(r)degrees(T) between 20 and 30 kcal/mol. We report in this paper densi
ty functional theory calculations of the O-H and O-C bond dissociation ener
gies of different hydroxylamines and alkoxyamines. Optimization procedures,
basis set effects, and exchange-correlation functionals are compared and t
ested against experimental data. Finally, the bond dissociation energy of (
N-tert-butyl-1-diethylphosphono-2,2-dimethylpropylnitroxide)R " (where R "
= benzyl, styryl), is reported. This last result is especially important si
nce SG1 is the most efficient to-date nitroxide radical in nitroxide-mediat
ed polymerizations of styrene and acrylates.