Theoretical Determinations of the Ambient Conformational Distribution and Unimolecular Decomposition of n-Propylperoxy Radical

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Molecules, spectroscopy, kinetics, environment, & general theory, 2005-04, Vol.109 (16), p.3637-3646
• Main Authors: Merle, John K, Hayes, Carrigan J, Zalyubovsky, Sergey J, Glover, Brent G, Miller, Terry A, Hadad, Christopher M
• Format: Article
• Language: English
• ISSN: 1089-5639; 1520-5215
• DOI: 10.1021/jp050444n

The conformational distribution and unimolecular decomposition pathways for the n-propylperoxy radical have been generated at the CBS-QB3, B3LYP/6-31+G** and mPW1K/6-31+G** levels of theory. At each of the theoretical levels, the 298 K Boltzmann distributions and rotational profiles indicate that all five unique rotamers of the n-propylperoxy radical can be expected to be present in significant concentrations at thermal equilibrium. At the CBS-QB3 level, the 298 K distribution of rotamers is predicted to be 28.1, 26.4, 19.6, 14.0, and 11.9% for the gG, tG, gT, gG‘, and tT conformations, respectively. The CBS-QB3 C−OO bond dissociation energy (ΔH(298 K)) for the n-propylperoxy radical has been calculated to be 36.1 kcal/mol. The detailed CBS-QB3 potential energy surface for the unimolecular decomposition of the n-propylperoxy radical indicates that important bimolecular products could be derived from two 1,4-H transfer mechanisms available at T < 500 K, primarily via an activated n-propylperoxy adduct.