Quantitative Assessment of Reparameterized PM6 (rPM6) for Hydrogen Atom Transfer Reactions
Toru Saito, Hiroki Kambara, Yu Takano
Department of Biomedical Information Sciences, Graduate School of Information Sciences, Hiroshima City University, 3-4-1 Ozuka-Higashi, Asa-Minami-Ku, Hiroshima 731-3194, Japan
We proposed a reparameterization variant of PM6, namely rPM6, aiming at improving the accuracy for opens-shell systems [1-4]. In this study, rPM6 was tested to assess its quantitative applicability to hydrogen atom transfer reactions mediated by high-valent metal-oxo species. The conventional PM6 and PM7 methods were also evaluated for comparison on the basis of either experimental or first-principles computational results [5]. Regarding bond dissociation energies (BDEs) for organic substrates, the rPM6 method performed the best with the smallest mean absolute errors from the experimental data. We found that activation barrier heights computed by rPM6 correlate with BDEs relatively well. Hence, rPM6 can be useful as a pre-screening tool, alternative to density functional theory calculations.
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