A theoretical, dynamical evaluation method of the steric hindrance in nitroxide radicals using transition states of model reactions.

ABSTRACT: Steric hindrance is known to affect the stability, reactivity, and radical trapping ability of stable nitroxide radicals. Therefore, a quantitative evaluation and prediction model of steric hindrance is needed to select and design the optimum nitroxide radicals for specific applications. In this study, a dynamic parameter of steric hindrance (DPSH) is proposed and its characteristics are investigated. Unlike using only the equilibrium structure to evaluate the steric hindrance, DPSH is a dynamic value calculated from the theoretical activation enthalpies for two model reactions of radical addition to olefins. Using DPSH, the steric hindrance was evaluated for a total of 43 alkyl radicals, nitroxide radicals, and radicals derived from phenols, and the results were compared with those of oth

SUBMITTER: Yamazaki Y 

PROVIDER: S-EPMC6937270 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature